M32, new Marstrøm project cat..

Ref: http://www.marstrom.com/index.php?action=get&id=95&category=1

Something new Marstrøm is working on. Wonder why when he already builds the Vx40? Also, why did they put flat foredecks on the boat when it is pretty accepted that a rounded foredeck is better to prevent pitchpoles. Am I wrong?

While on the site, check the carbon fiber RIB they are building for the Vx40 folks.. A carbon RIB.. I am left speechless.
http://www.marstrom.com/index.php?action=get&id=97&category=1

I guess that an F18 won't be far behind now that their Tornado market is in jeopardy

There is one thing about Marstrom that I never understand.

The reasoning behind their products and why they try complete new designs without any demand or clear pathway to market/succesful class.

Two products of Marstrom are fine.

The Tornado and the A-cat class, both classes were however formed by other people and other builders before Marstrom entered the class for a piece of the pie.

Then they did the M18 and M20, both of which failed spectaculary. There was simply not enough demand for these boats and really nobody was waiting for them either. They sold a handful because of the carbon BLING factor and that was it. Dissatisfied with their allround performance their owners are converted them to sloops.

Seacart 30, by their own admission 15 build and spread over 7 countries, some as far away as south africa. This class can still go either way, so we'll give them another few years to proof the class and concept. However, I do fair they will have a tough battle with the Corsairs and Farriers. But thus far it is not a break through yet.

And now the M32 ?!

[censored], How many new exciting 28 to 35 footer cats and tris have we seen launched in the last few years ? On the swiss lakes we see a new such class every 2 years. And of course we have the Extreme-40, a design and class build by other people although Marstrom builds the boats. How many so far 15 boats as well ?

Who is being serviced by the new M32 ? Who is waiting for it ? Who will buy it and where will they race it. It is too big for beach cat regatta's and to small for of shore races or record attempts. And if it wants to launch its own high profile OD cup cirquit then it has to first compete with the Extreme-40's and come out on top. The E-40's of course having a considerable lead on the M32 in this respect.

But lets say that is all solved somehow. Lets look at the design, another uni-rig ! Say goodbye to the M32, friends. It is another boat who's crew will be praying for perfect upwind beats and claim mastery of the seas by reaching the A-mark first. The first time it does Texel it will be hunted down by smaller overweight sloops (costing only only 1/10 of an M32) like a pack of hungry wolves chasing a wounded kariboe.

And even if it doesn't break this time and comes in 15 minutes before the fleet, I can already hear the comments. "100.000 Euro's devided by 15 minutes = 6666 euro's per minute gained". Because there is one thing that Marstrom garantees, it will cost you a bundle. Ergo only some millionaires will buy it and then loose interest when they discover that pulling 450 kg across the beach is indeed hard work. (something they are not used too ?)


Summarizing, Too large, To heavy (even if it is all carbon and light for its length), too expensive for a recreational daysailor, Too clumpsy to trailor about, not practical as a beach cat, not a practical off shore racer (no shelter or storage rooms), Not a cruiser, Not a Extreme-40, No class and No market demand for such a boat.

Anybody want to place bets on whether this new design/class will be making an impact ?

Wouter

All of what Wouter says is true...and can be applied to the R33's produced here in the US.

I feel Marstrom makes these kind of boats more out of passion and wanting to have fun than to make a serious business profit from it. Afterall, the core business at Marstrom is in big boat spars and aeronautic parts.
\

Wow, Wouter, you and I see exactly eye to eye on this one. There's a first time for everything, right?

Sail up agaainst thr ARC 30?

The add says, "Will beat a 40 footer in speed..." Was he talking about a Volvo Extreme 40 foot cat, or a 40 foot racing mono? It also says it weighs 450KG. What does the Volvo 40 cat weigh?

I think it already has as it's being talked about.

Will it make more people sail cats?

I dunno, but if one person buys one who would have bought a monoslug then that has to be good news.


If Goran wants to spend his research Euro's on this then he is to be applauded for making progress. You may not agree with what he is doing. But he is doing something.

Friend of a Friend has a SeaCart and loves it to bits!

Ohh, I respect Goran for doing stuff, that is not the point.

I only wish he does stuff that has a much better chance at succes and progress the cat scene that way. The impact of "outliers" is severly limited if not negligiable.





It is the better of the design in my opinion but it isn't any different from the Corsairs and Farriers and as such it doesn't progress the scene beyond the point that they have brought it too. Ergo it doesn't matter whether the Seacart fails or succeeds as the scene will remain as it is.

Wouter

I would LOVE one of those SeaCarts, but aren't they about 2-3X what a Corsair costs? Are they 100% carbon?

The Volvo X 20 weights 1200 KG which is quite lighter than the old Formule 40 we had 20 years ago, which used to weight 2000 kg with 90 sq mtrs windward.
Marstrom's idea is probably to maximize the ratio: crew weight/boat weight,which is quite similar to horsepower/ weight, that is why with 450 kg, less sail area she will be probably faster than the VX 40.

Don't you mean Volvo X-40's? The Volvo X-20 is a different catamaran.





Thank god for measurement rating systems.

Texel rating Volvo X-40 (with 4 people on board) = 69
Texel rating M32 (with 3 people on board) = 78

Therefor Texel says that the X-40 will beat the M32 by 78/69*3600 = 470 secs with the X-40 finishing the course in exactly one hour. That is roughtly 8 minutes. 13% speed difference is a whole lot for improvements in efficiency to overcome.

Even with a 25 % jib the M32 will only lower its rating to 73 and still be beaten by the X-40.


Now indeed, this all dependent on how much faith you put in Texel to produce accurate rating numbers. However, she was the only system (together with schrs) to have projected the F16's correctly from the very first moment these were launched. Additionally, any errors in this system are made negligiable when the two boats being compared are very similar in setup and general size. I feel this is the case between the X-40 and M32. The M32 being allmost a 80% scale model of the X-40 but without a jib.

Wouter

I know the seacart flies on one hull only most of the time at hyperballistic speeds, I thought farriers and corsairs were a bit more sedate and generally sailed on two which really puts the seacart a league ahead in performance , or i'm wrong <img src="http://www.catsailor.com/forums/images/graemlins/crazy.gif" alt="" />

ps when I get too old for beach cats , the seacart's the only one that really gets my vote so far !, just have to wait 20 years for them to depreciate !

The seacarts are fast, and indeed designed to be sailed on one hull. As for cost, they are way to expensive. My sailing partner, Frode, and I have a dream about a 28 foot homebuildt racing trimaran in wood. One day we will realise the dream and see what we can do compared to a Seacart or any other multi. Formula28s from the early 90s are still able to give the seacarts a run for the money in the right hands.
I dont think the M32 compares well to the Vx40. It dont have a jib and everything that implies and it dont have a similar hullshape as far as I can see. I dont see the business model behind the boat either, but hope Marstrøm do well!

What do you think about a carbon RIB.. That had me thinking "are these guys nuts??!?".

Though the SeaCart is a thing to behold...I would not want to own one...it is less practical than the Farrier concept since it must be de-beamed for trailering and cannot fit a standard width slip (a Farrier can fold).

Also, I distinguish Farrier's from the Corsairs...the former being my much preferred choice.

Another member in this concept range is the Catri...lighter than a Farrier/Corsair, foldable with Bruce foil assist. However, as Luiz can test, poor/no manufacturing support is the deal killer.

More info on the M32.

The boat will have water ballast to improve upwind speed and to prevent the boat from capsizing when it is moored. The sail area is roughly 55 m2 + mast area and it will start to fly a hull in the same windrange as the M20. The price will be roughly 100 000 Euros, that is 1/3 of the price of a Vx40 (reducing weight, size and complexity of a boat reduces the price a lot).

One of the reasons for Uni rigg is to keep the cost down and have a "clean" boat. The boat reminds of a scaled up M20 and that means that the number of fittings and manufacturing steps will be similar to the M20 (but you need more carbon).


/hakan

And I'll bet the first thing a new owner does is try to add a jib! <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />

You can't just add more engine to a car, you must stay on the road also....

Some kind of light wind jib is planned but in higher winds it will be uni mode. Adding structure for a jib makes it more complex and more expensive.

The limiting factors for laminate thickness on this size of boat is from the sailing loads, for a beach cat you have other limiting factors like crawling crew members during a capsize, boat handling on the shore and so on. This is probably the reason why you could add a jib to the M20 without any extra carbon in the hulls.

The M32 design uses the twin forestays to get the platform stiff, if you remove them you must replace the twin forestays with something else. The bridle will create high point loads on the hull that must be taken care of and the total side load of the hull will increase.

This boat is uni rigg, if you don't like that buy something else....

/hakan

The M20 does need additional structure to handle a jib.

The cost to have the M32 able to handle a jib woulb be very minimal and the performance advantages are well worth it.

Just compare Xander's M20 to Gorans in the last Texel..... Jib is king.

Macca, where did you get that info from? I talked to Goran about it and according to him the hulls has no extra carbon to handle the increased side loads. Some Dutch guys had a bridle between the hulls in the beginning but they removed it later on.

M20 was first and second round Texel two years ago, uni is KING (or can you really use a race around an island to measure this.....:)

/hakan

I have photos of M20 being modified with new bulkheads in the bow to take the jib loads. Plus a new order we placed with Goran specified the extra bulkheads.

2007 Texel really showed how much faster the sloop M20 was. and every distance race in Holland this year also showed how much faster a sloop M20 is.

Thanks for the info Macca, I probably need to check my source harder.....(setback!)

The sloop vs uni debate has been running a long time, and it's hard to get good data. We can of course start that thread again but we lack data to be able to say when and where the diferent rigs will will be better or not.

The only data that I found from the last Texel that could be used to determine the speed of different boats was an upwind leg, and on that leg the M20 uni was the fastest. Texel is quite a tricky race with several checkpoints you need to pass, I've tried it once in the M18. The first checkpoint is to get out from the beach and the we have this massive start, currents and so on.

You refer to several unnamed races in Holland where the M20 sloop "ruled", but I think you need to do more research before you use it as a fact. Who was sailing the M20 uni and who was sailing the M20 sloop? (The top guys in Holland prefers the sloop version and that will of course make the sloop to look faster....).

/hakan

It also has been decided a long time ago.

Afterall, Orange 2, B&Q and IDEC 2 were all sloops (as were all other record breakers) and that is not because the uni-rigs are better. The only records held by uni-rigs at this time are the 500 meter straight line dash, meaning the windsurfers. The 1 nautical mile record is held by Hydropthere and that is a sloop again.





The standard defense of the uni-rig sailors. Last time I checked, reaching the finishline requires the completion of at least a single downwind leg as well.

There are no prizes given for reaching the A-mark first.





And the sloops are not held back by this because ......... ?





Only a foolish boxer would claim the world championship after winning his first contest in a series of 7 prior loses.

And why can't you use a race around an Island to measure the performance of a sailing vessel ? Racing sailboats is not like a track event where everything is tightly controlled. Why should the course be adjusted to suit the design and not the other way around. If the uni-rig is King, shouldn't it be King in a wide variaty of situations ?

If not, then of what exactly is the uni-rig King ?

Wouter

with unlimited sail go sloop.. for limited sail go cat..

If sloops ruled completely both the "A" and "C" class would have remained sloop..

Do you know what these boats have in common?
Crossbow II
Sailboard
Yellow Pages Endeavour
Hobie Trifoiler
Sailrocket
Monofoil
Parliers Mediatis (60 foot catamaran)
C-class
A-class
...
They are all unirigs with or without sail area restrictions. Some of them have two or more sails but they do not work together like a main and jib.
The first Crossbow (proa) had main and jib and reached 32 knots, the second one, Crossbow 2 (cat), had one main sail on each hull and they where positioned to get clear air. Crossbow two reached 36 knots.

How many high speed boats uses main and jib?

Here's a list of the world speed records.
Outright record
48.7 knots Board (unirig)

8 m2 class
Board (unirig)

10m2 class
Board (unirig)

A-class
Longshot (unirig x 2)

B-class
Yellow Pages Endeavour (unirig)

C-class
Yellow Pages Endeavour (unirig)

D-class
Techniques Avancees (unirig x 2)

No sloops!?
/hakan

And what exactly is limiting the M32 sail area ?

I rest my case ! (after the next posting <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />)

Wouter

Yes, none of them have won a regular sailboat races or regattas.

Neither is any of these holding any sailing records at this time EXCEPT the 500 meter one-way dash.

Now if the M32 is intended to wait years for perfect conditions and sail in the French trench in order to reach the 50 knot barrier before any windsurfer does then it will have a glorious future I'm sure.

If is designed as a regatta boat then I think it has some marketing if not preformance problems.

Wouter

I already can smell a race in the air: Dutch F16 team challenging Canada in the C-class! Their secret weapon of hope: a jib!

Hopes die last, in contrast to jibs...

;-)

Well, if an F16 were to beat the most modern C-class then the uni-rigs really do have a serious problem, won't they ?

Why not much up an F16 against IDEC 2 ? Is that dissimilar enough for you ?

Ohh, yeah I forgot, IDEC 2 is also a sloop.

Hey ?!!!

Lets race an C-class against IDEC 2 across the oceans. That'll show the superiority of the uni-rig, I'm sure !


We all know it and have known it for centuries. Sloops outperform uni-rigs around a race course in all situation except the single situation where the sail area is so severly limited in overall area that it implicetly rules out jibs by definition.

That is like saying that the best boxer is the guy with only one arm as he won his matches against all other boxers who tied (at least) one arm to their backs.

Still doesn't say a damn thing about what happens when "the other" boxer can use both arms if he has them.


Hey, look how stupid Ellen Mac, Francis Joyon and Franck Camma are. They could have bested the round the world record much better if they had used a uni-rig ! Hell, any A-cat sailors could have told them that uni-rigs are so much more efficient that it is actually slower to try to break the records using a jib or, God forbid, that oversized jib called a "code O" or "screacher".

And those spinnakers, HAH !

Ever seen a spinnaker on a C-class or used in an A-class race ?

Surely this proofs that they are just useless pieces of cloth hanging out in front.

What more evidence do we need to confirm the fact that F18's never beat A-cats in a straight up course race.

If a spinnaker was in any way effective then the true innovators of the catamaran sailing scene, the A-cat sailors, would have invented, developped and incorporated it long before any other mortal would. The fact that they didn't is sufficient proof to its ineffectiveness.

If only we all pray to the A-cat God ! And stop our races after reaching the A-mark.

Wouter


Dirk, are you sailing an A-cat ? Because it sure doesn't look that way with that big green spinnaker out in front. I guess you are slower that way when sailing downwind then when sailing with only a mainsail (uni-rig) right ? Right ? I mean no C-class design is using spinnakers right ?

Matt and Gina, on their Blade F16 with jib, already have beaten several A cats, I-20's F-18's, boat for boat, around the same Windward-leeward course in the Alter Cup Area D eliminations at GYC in November.

Uni is fast in lighter air, but when it starts blowing and you need to depower the top of the sail, the boat with a jib can stay powered up in higher wind, due to the lower center of effort of the jib vs. the taller masts of the Uni rigs.

If you have a fixed sail area, I think putting some of that area in a jib vs. at the top of the mast makes more sense but only if you are out in more than 10-15 knots of wind. Below 10, it's probably faster to keep the sail area up top on the mast.

I know,

Actually what most fail to understand is that direct comparisons between sloops and uni-rig can easily be made inside the F16 class and actually have been made often as a result.

Basically choose your crew make-up and have one team (or skipper) sail with a jib and the other without it. Everything else stays exactly the same and can therefor be taken out of the equation. No sail against eachother and switch boats and do it again. On average you will come to one conclusion. Sloop is faster.


If think we did exactly this when you were over Tim. I was uni-rig with Gill and you were sloop rigged with Geert (and an underpowered Ullman mainsail. You guys would eventually overtake us on the upwind legs, no matter how hard Gill and I tried to defend our position and give you guys bad air. You guys just had more speed and as soon as you had passed us you would walk away.

We were sailing in what ? 10-12 knots that day ?





There is limit to how much area you can put in a mainsail, but you can ALWAYS add a 25-35% jib to any given mainsail. In very light airs the boat sails mainly of the top of its mainsail. The jib is not not helping much here, but it also isn't holding you back much. So when both tops of the mainsails are the same then in the light stuff the performance of the sloop is not too different to the uni-rig. When the wind picks up then the sloop will become significantly faster.

An excellent setup for record breaking. Very limited drawbacks while having frequently encountered significant speed advantages.

Wouter

Back to the M32, that boat is Uni rigged on the upwind and sloop on the downwind. In that way you get the high efficiency and low drag of a single wing on the upwind (like all speed machines seems to choose) and then switch to the high lift mode with the sloop configuration on the downwind.

The big problem for all beachcats during a distance race compared to the bigger multihulls are the speed gaps you have where you can't use the spi and you are not sailing high enough for double trapeze reaching. The bigger multihulls have screachers and other stuff that the smaller boat lacks. Here the sloop has an small advantage compared to the uni since it has two high lift modes to use, spi or jib which covers the gap a bit better than the uni. On the A-class with spi this gap is from 30-40 deg from downwind to about 70 deg from downwind where I can start to trapeze with main only.

/hakan

Ever time this claim is made without any regard for the fact that this is entirely based on a very selective reading of the situation.

I would most definately call boats that for example hold the 24-hour distance records as speed machines. Not a single one is a uni-rig here, neither any multihull or monohull in this respect.

It is also very "uninformed" to refer to the 500 meter distance record holders (all-out speed record holders) as upwind machines. None of these records are achieved on any course that even resembles an upwind course. As good as all courses used for waterborn speed runs are downright beam reaches or shy broad reaches.

Throwing in the windsurfers as proof against sloops is also a bit disingenious. Afterall, how would a windsurfer be fitted with a jib that has a tight leech ? The technical problems in this respect are far more effective in exclude any jib then any performance oriented considerations.

The simple fact that the sloop rigged Hydropthere is the current 1 nm speed record holder and a very serious contender for breaking the 50 knot barrier first is simply and totally ignored. Why isn't a windsurfer or a winged uni-rig like Yellowpages/Macquarie innovation holding this record ?

All my points made point back to the following observation. There is a group in sailing that has determine on some grounds that uni-rig are superiors to sloops (given any situation) and they are selectively finding proof for that believe while ignoring commonly available data that invalidates this believe.

Now, I'm not denying the properties of a uni-rig; I'm just highly critical of the intepretation, extrapolation and believes that are derived from these. These simply don't hold up to basic scientific discourse that demands that a given statement must hold under all "allowed" situations.

The claim that uni-rigs are more performant (speed) is so generally worded that is allows all possible situations as counterproof, and many counterexamples can be found this way. Ergo, this claim and similar ones are scientifically disproven and have been for many decades if not centuries

Sorry.

Wouter

Wouter:
In your side by side sloop v unirig in F-16 post (top of pg.4) is not the jib added area to the unirig main, i.e., the 2 boats have the same mainsail?

Is not the jib a high lift high drag leading edge device and subject to this article: http://aerodyn.org/HighLift/multi.html

I'm just trying to understand, and I thought this article applied in principal. I remember Randy Smyth pulling to shore and removing his jib in a Worrell when it was blowing hard and it helped. He won that leg, but of course there was a lot more going on.

And it seems to me Hakan is talking about a unirig w/ genaker setup vs sloop w/ genaker.

Also it seems to me that most of the vessels you cite cannot reasonably be used to establish anything relative to beach cats or even this M32. Hydroptere is a large hydroplaning cat, at least some if not many of the others are monohulls

Steve,




Indeed, both sailboats have the same size sail area. Note that is not cheating by giving one boat more total sail area then the other, even when indeed one but has more then the other.

The point of contest here in the M32 thread is about what is best for a new design performance wise. As it is a new design altogether, one can set its max sail area limit at ANY level. Of course their will be levels where not all sail area can be put in the mainsail, either practically or efficiently. With the F16's the mainsails are pretty much at the max area you can get in there while maintaining an acceptable aspect ratio (efficiency) and control.

Back to out topic. A completely new M32 design. The experiment that can be had with the F16's that relates to the M32's is this. Given the M32 the largest mainsail it can have efficiently or practically. That will be our uni-rig. Now make a second identical boat (same mainsail etc) but a 30% jib is added to the setup. Afterall, you can ALWAYS add a 30% jib to any conventional catamaran setup. Any problems that are encountered can be adressed by bridle foils and other simple solutions.

So the choice or rigs is not limited to either a sloop or uni-rig of the same overall area, but rather between a uni-rig and a sloop with 30% more sail area while using the same size mainsail.

It is this comparison that can be easily tested using F16's. As both setups, F16 and M32, are very similar in overal design the result can be expected to hold for both classes. In the F16 class we found the jib makes the boat faster, even on upwind legs. You point lower but move sufficiently faster to arrive at a higher VMG; and that is what everything is about. Brute force (=speed) winning out over efficiency (=pointing).




High lift yes, high drag not necessarily.

The thing to note about the sloop rig versus the uni-rig or even a rig consisting only of the jib is this :"When the two sails are set right relative to eachother, they mutually influence eachother in a positive way".

Because of the close proximity of the mainsail the jib is "supercharged" and is producing a whole lot more drive then this jib sail would produce without a second sail directly to its rear. Interestingly enough the jib will also operate at much smaller angles of attack while producing this disproportionally high drive forces because of the interaction with the mainsail. The mainsail itself produces less drive with a jib in front then when it would by its own, but the loses are smaller then the gains made by adding the jib. Also the flow of the mainsail is smoothed out and it is far less suseptable to stalling (losing attached flow). Its drive had become alot more dependable and it is easier to have it ride the groove constantly. This is the positive effect of the jib on the mainsail.

The net result is that significantly more drive is produced by a sloop rig (using same size mainsail) then a uni-rig whithout losing too much pointing. Actually the loss in efficiency per sq. meter and loss in pointing angle are overcompensated by the increase in speed due to having more sail drive. Ergo, the boat points lower with less efficiency per sq. meter but it still attains a better VMG and reaches the A-mark sooner on upwind legs.

In this role it is not to similar to the article you provided. It is however on course with high angles of attack. These course are reaching legs and broad reaching legs without spinnakers. Here the jib acts in much the same way as the slats and flaps of an aeroplane. These devises are used on a plane when the planes travells very slowly (landing / tak-off) and flies with large angles of attack. Here it needs to provide alot of lift without risking the wing stalling. This is similar to what a sail boat encounters on reaching and broad reaching legs. On these legs rig drag is not a major consideration as only a smaller portion of the total is acting along the centreline and limiting boat speed. The other portion is acting prependicular to the centreline and only loads up the daggerboards. The deeper you go the less rig drag is holding you back. Actually on a pure downwind leg it is actually the rig drag that is propelling you forward. So somewhere halveway there is a point were all rig drag is acting perpendicular to the course travelled and rig drag become an totally unimportant factor.

Here the jib makes the boat significantly faster then a pure uni-rig (no spi) by being able to produce maximal saildrive (30% more due to having 30% more area) at significantly larger angles of attack (= sailing deeper) while also delaying the stalling of the rig. Where some of these factors worked against one another on the upwind leg, limiting performance gains there, they are all working together to maximize performance on the other legs (reaching and broadreaching). On the pure downwind leg sail area is all sail drive is drag related here. Goosewinging the jib increases the area by 30% and results in 15% speed increase for that fact alone. Goosewinging is setting the jib to the other side of the boat then the mainsail is.




It should actually work the other way around in these windy conditions. A jib adds alot of drive low in the rig. Meaning it can add 30% drive for only 10% increase in heeling moment.
Do this mind experiment, Say both a uni-rig and sloop rig are 20% overpowered when sheeted tight. The uni-rig needs to loose 20% of the saildrive to stay upright. The sloop rig (with same mainsail) can remove the jib and 20% of saildrive and effectively become the uni-rig. But it can also depower the mainsail to 70% saildrive (30% loss) and use the addition 10% loss to gain back 30% drive through the jib, coming out at a 120% of the saildrive of the uni-rig.

Which one of the two do you think will be faster ?

An added drawback of the un-rig is that it depowers mostly by twisting off the leech and this impacts strongly on its pointing ability. So it looses both power and pointing by having to depower the rig. The sloop was already sailing lower then the uni-rig and the drive produced by the jib is totally UNAFFECTED by any mainsail leech twist. Basically the sloop can keep pointing the same as it was before while the uni-rig has to come down.





He is, but even in the setup we have found that a sloop F16 is faster upwind then a uni-rig F16 when sailed by the same crew.

Interestingly enough we also found that we need to add another person to the sloop F16 is bring it down to the uni-rig performance; this is reflected by the 1-up F16 (uni-rig) being just as fast around the course as the 2-up F16 (sloop).

Surely, having one person extra on board is a performance hit. The jib is the element that adds enough drive to speed the boat back up again.

This goes directly against the commonly "accepted" A-cat wisdom where jibs are regarded as nothing but trouble. Some even believe that adding a jib will actually make a boat slower. Of course these persons overlook the fact that there is no physical requirement to take the jib area out of the mainsail. You can always just keep the mainsail area and just add a jib (+ is area) to it (the total).

And this is where the M32 design will fall flat with respect to its competition, just as the M20 design does.





Longshot and the hobie trifoiler, as suggested by Hakan, are actually full foiling craft as well. The windsurfers being fully planing craft and the C-class cats use a solid wing as a sail.

Why can he make such comparisons between widely different craft to argue his case and I can't ?

I just showed the uselessness of his examples by producing similar counterexamples.


Having said all this I invited everybody to do their own experiments. It is very simple.

Get two identical sloop rigged boats and find a crew that has a similar skill level as yoruself. Remove the jib on one boat and race against one another in different conditions while swapping boats and possibly the sails. Your findings will most probably be that the sloop is faster, even when going upwind.

Ergo ADDING a jib (not cutting it out of the mainsail) makes a sailboat faster. So if you make a totally new design where you can set all limits yourself, will you decide to make it a un-rig or a sloop ? And that is the M32 & 100.000 Euro question.

Wouter


P.S. anybody wanting to read more about mainsail and jib interaction or looking for scientific sound proof; read the articles written by Arvel Gentry. He was the first to make his proof scientifically sound when the rest was still acting on "believes" and gut feelings.

wouter,

in most cases, adding sailarea makes a boat faster.

if you put that extra sailarea you propose to put into a small jib mounted low to the platform, into the mainsail (e.x. higher mast), I doubt the sloop will be faster than the uni in light air. light air is interesting because a boat and sail can be sailed to it's full potential. A and C class both allow you to sail with a jib, still even 60 kg light A cat sailors who might start pulling cunningham at 2bft are not doing it. in contrast 'heavy weather' boats like the F18 seriously struggle in light winds. If class restrictions would allow them to put the sailarea of the jib into the main (with a longer mast) my guess (no science) is it would perform better than the one with a jib till the moment the heeling moment can no longer be compensated by the rightning moment. by the nature of the rule the uni will be earlier overpowered than the sloop as it will be earlier lacking power in light airs. the reason why so many (succesful) boats and classes have jibs is to make them suitable for a wider range of conditions by giving up light air performance same time. I assume the AM2 catamarans on the Swiss lakes are a good example... their top mast gennaker are cut so flat they seemed to be usable upwind. saying this, if you want a good alrounder, a sloop offers a wider range (something you need on a RTW) while if you design for a particular small windrange, a uni wing will probably perform better.

by the way I would be highly worried if by my next step on an airplane I would notice jibs in front of the wings ;-)

You are right there Dirk and I have said so many times.

When the total sail area of a boat is limited to a rather low level, then putting everything in one sail is best. When it is not then "slotting" the rig and placing more canvas low is better.

My reasoning is only that limiting the total sailarea to such a low level is nothing more then an arbitrary choice.

There is no physical or technical reason to limit the total sail area to such low totals. Ergo there is no performance oriented reason to favour an uni-rig over a sloop rig for new designs/classes. And that links directly to my amazement about the M32.

Everytime the discussion hangs up on the CHOICE to limit the total sail area to very low totals. And every time I say something like; increase the sail area limit of the A-class to 20 sq.mtr. and see what happens then. I can garantee you that you will not see any uni-rig anymore.




What are slats and flaps then ?

Wouter

Slats and flaps are high lift devices (that asume you have good knowledge of) that you use when you have a high angle of attack, normaly during take-off and landing. If you would have the slats and flaps out when you fly with low angle of attack, which is the case during normal fligh, you would add drag. The drag must be quite high since all planes remove them during normal flight.

Now back to sailing!
A sloop always sail with a bit of flaps and slats out on the upwind where you have low angle of attack, but the uni can remove them completly during the upwind by taking down the spi. On the downwind where you have high angle of attack both the sloop and uni pulls out the high lift devices (the spi)

/hakan

I think you have a speed issue with that logic Hakan. My understanding is that you need to go at a certain speed before removing the slats/flaps pay off. Just look at a very specialized plane like the Fieseler Fi 156 ( http://en.wikipedia.org/wiki/Fieseler_Fi_156 ).
Sailboats dont move that fast really, and our airfoils are pretty high lift anyway. In my opinion the drag reduction of removing the jib in an unrated sailarea class will probably not pay off. But now we are back to the uni vs. sloop discussion we had just a couple of months ago. Like I said then, we simply dont have good numbers on the question, so we will not be able to close this discussion no matter how much logic we apply.

There is no need for any logic, just do the experiment for yourself everybody. Get two identical boats and removed the jib on one of them and see for yourself whether an ADDED jib is making you faster or holding you back.

When encountering a uni-rig believer, just ask him to place to largest possible mainsail on his boat and then go out and put a jib on there as well while keeping the mainsail and do again some on the water testing. He will huff and puff about maximally allowed sailarea and abruptly forget about any efficiency claims he made earlier. Of course you comply with his objections by fixing the maximally allowed sailarea to the total of the max size mainsail and jib combined. He will then only huff and puff indelligiaby and know he has been beaten.

Afterall, why does anybody have to agree to a such a low total sail area limit that it almost explicitly rules out the use of a jib ?

Nough said !

Wouter

Right, but to make the experiment fair you would have to add the same area to the main of the uni, unless both boats are overpowered already. There is no proof in any of these arguments, just examples and applied logic.
I am certain there are crossover points on the performance plots for both types of rig, and I have some toughts about where they might be. But until someone do the tests and produces some real numbers.. 'nough said.

I still think doing a carbin fibre RIB is outrageous, but nobody seems to have notices in all the uni vs. sloop noise.

I don't do RIB's !

Besides, it is just another example of carbon fetishm. Hardly a new discovery with Marstrom

Wouter

Dear Wouter, why do you constatntly say the sailarea on the A class is rather small and uses that as an explanation why it has no jib? In relation of sailarea/weight the A cat is having the most sailarea compared to it's weight of most of the boats discussed. For the same reason, at 1bft adding a jib might increase the upwind speed of an A cat, from on +2bft I am pretty sure the jib will slow you down as you are fully powered up already without anyhow. Downwind a spi is more efficient than a jib, so if we discuss outside class restriction, with any boat you would go for a spi.
F18HT shows it as well as the earlier Ventilo 20 (which regulary outsailed the Tornado).

A cat 75+75/14 (m²/kg)=10,7
F16 uni 105+75/15 (m²/kg)=12
F16 sloop 105+75+75/18,7 (m²/kg)=13,6
C Class 130+75+75/25 (m²/kg)=11,2
F18 180+75+75/21,1 (m²7kg)=15,6
Carbon RIB (for Rolf) ;-)
M32 ?

I'm not saying a uni-rig is without advantages; Hell in 60 minutes I'll be landyachting across the beach using a single mainsail.

The whole point of the exercise is to put some reality into the myth-making that happened around the uni-rig properties.




Actually it doesn't, not even by a long stretch. You are forgetting the spinnakers that many boats nowadays have. I mean, EVERYTHING is counted as sailarea or nothing is. On larger boats you have the code 0's and screachers that can be set even on beam reaches and low upwind courses.

When looking at spi-less setups there are also very simply counterexample in the beach cat field,

18 sq. 75+75/18.0 = 8.33
F16 sloop 1-up 107+75/18.7 = 9.73
A cat 75+75/13.94 = 10,8
F16 uni 1-up 107+75/15 = 12.1
C-class 200+150/27.87 = 12.6

Interenting to note the C-class specs !

Actually even the old (underpowered) geezers, when sailed singlehandedly, are not that far off the A-cat/C-class specs.

Hobie 16 150+75/19.5 = 11.5
Hobie 17 sport 150+75/18.86 = 11.9
Prindle 16 135+75/17.34 = 12.12
nacra 5.0 147+75/17.82 = 12.5

Now how many of us have singlehanded sailed or raced boats like the P16, H16 and nacra 5.0 and others in the past, over a wide range of conditions ? I think we can all attest to the fact that they were easily enough controlled. Basically all Hobie 16 that are singlehanded just HAVE to fly the jib as on that design the jib luff is also the forestay.

Now I have singlehanded the F16 singlehanded as a sloop as few times and it is pretty calm and easily controlled that way. Lots of power low in the rig giving a stable consistant drive.

And I would actually argue that boatweight is not very important when analysing heeling and righting forces. A better comparison would be to look at sailpower relative to the product of the width of the boat and the weight of the crew. Why, because even on a singlehander the boatweight is only contributing about 25% of righting moment.

When looking at the A-cats and F16's the difference in boat weight is 43% but the difference in righting moment is only 19%.


So actually when looking at the real heeling moment estimate (boat weights included) then some of the other boats mentioned so far have higher sail area to righting moment ratios then the A-cat has. And that makes the A-cat relatively underpowered in my book; note that the F16 is the only MODERN boat in the following listing next to the A.

F16 396/18.7 = 21.2
Hobie 16 435/19.5 = 22.3
Hobie 17 sport 446/18.86 = 23.6
A-cat 334 /13.94 = 24.0
Prindle 16 423/17.34 = 24.4
nacra 5.0 446/17.82 = 25.0
F16 396/15 = 26.4





If there is no restriction on the total amount of sail area that can be had then we see sailboats (not landyachts) with a sloop rig and a spinnaker.

Indeed, the spinnaker makes the jib almost negligiable on the downwind legs but it doesn't affect the jib added performance one bit on reaching legs and on upwind legs. Basically, adding a jib costs you nothing on the downwind legs but still increases performance on all other (non-spi) legs.

Wouter

If this is a true statement then sailing a Hobie 16 without a jib in say 5+ beaufort winds (=overpowered) should be faster then a similar crew sailing the sloop H16 in the same conditions.

I know you sail Hobie 16's Hakan, so don't take my word for it and just try this one time. And that goes for everybody out there. Just try it yourself. You'll all see for yourself what happens in real life.

With respect to A-cats, I have the exact opposite opinion :

An jib added A-cat in 1 bft will not show significantly improved speed in any way. This is because of the way the wind is made up at these low speeds, laminair flow patterns. In effect the range of height were the jib is there is simply very little energy (windspeed) that can be harvested. OVer 2bft the winds switch to a turbulant make-up and energize the layers much closer to the watersurface, now the jib will start pulling and add performance to the whole boat. In big winds all the depowering is done by losing drive high up in the rig which means that the top of the mainsail is switched off. The jib will in these conditions just continue pulling at full throttle because its heeling leverage is so small that it is pointless to depower it. The fact that at big winds the leech of the jib is adjusted as well is the result of the mainsail trim having been altered and the arrive back at the optimal interaction one has to adjust the trim of the jib accordingly.

Wouter

I want to end my postings in this thread as I'm in danger of rehashing my points endlessly and I got some stuff to get done; like repairing some landyachts. By the way Dirk, you are warmly invited to come and join me at landyachting some time.

I just want to say that this whole discussion is just about nuances and that even its heated status does not deminish the A-cat design and A-cat class in any way. The setup they have now is the best that can be had under the specifics (limits) of their class rules. The heated discussion about unis or sloops doesn't affect them as it assumes that the design is unlimited in any way but the need to maximize speed around any given race course. Class rules very much go against such a free environment and so too the A-class rules. Otherwise the A's would have fitted spinnakers a long time ago.

I just hope that readers have read the posts with interest and have looked at the situation from several different viewpoints after making up their own minds just as the designers of IDEC2 an the new C-class champion Alpha have done.

I hope to have argued convincingly that sailboat design is simply too multifacetted to be able to capture it in a few simple design rules. Of which of course, "uni-rigs are best" is one such example. The other of course being that "Full foiling is fastest". I think the recent C-class match where the real racing was between the non-foiling Cogito and Alpha has shown that it is just not that simple. You can't just look at the results in say the moth class and then argue that the same will hold for all other classes. Again, class rules do play an important role in how the fastest setup inside a given class will look like. As such a different set of class rules can easily favour another setup. I hope to have convincingly argued that part of the situation.

Good luck to everybody and have a excellent weekend.

I'm going landyachting now ! (where spinnakers and jibs haven't been seen for centuries ! )

Wouter

This discussion reminds me of this Monthy Python sketch:
Monty Python - Argument Clinic <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />

Wouter the 18sqm weight is 170kg..

Kinda makes a big difference!

That is the NACRA 18 square. This is a different boat then are found in the 18 sq. class. It was mainly sailed in USA and the lightest full carbon boats were very close to the A-cats in overall weight even when being over 3 mtr wide. Now the class is dead.

Interesting detail is that Wild Turkey was the first non C-class catamaran to fit a wingsail, it was an 18 sq. boat. The NACRA 18 square never got passed a large roached pinhead sail.

Wouter

Well if it's dead, then what is the point of using it?

thanks guys

learned a lot from this thread

will be interesting to compare sailing with and without jib on our smallish lake this summer with this thread in mind

Hi Erice,
be a bit careful when you compare the boat with or without the jib. A boat designed as sloop will work best as a sloop, if you remove the jib you will get a lot of weather helm due to too much load on the rudders, and the main needs to be cut differently if it shold work alone without the support from the jib.

/hakan