Can you please elaborate on this comment of yours? I dont understand it.

The graphics have been long gone. They were scratched up pretty bad in our last hurricane. Its Crazy with a Z. The font makes it look like a E.

Do you do graphics?

Wouter,

A while back in this thread, when discussing aluminum versus carbon masts you stated, "UV damage (5.5 months a year) and durability. / Alu wins out big in this respect."

What is your basis for this statement? Particularly the UV part. I thought most carbon masts were coated with something to make them UV tolerant. For example, Hall Spars says their A-class mast is coated with awlgrip. Does your statement concerning UV damage apply to coated carbon masts?

Geoff
(I17R)

We have found over several years that carbon masts are the equal, or in most ways superior, to aluminium. The UV that is often talked about is a “non event” as all carbon masts are coated with clear polyurethane before use (or should be) this totally eliminates any possibility of UV damage. The “strength” of a carbon mast is in all ways better in practice, than aluminium, other than direct impact. Though in a direct impact situation a carbon mast can “break” whereas given the same impact on an aluminium mast, it will most times “bend” to the point that there is a fold or crimp on one wall, which generally leaves that mast beyond satisfactory repair. A broken carbon mast can be re joined without any major dramas, if you are familiar with the correct procedures. An aluminium mast will “corroded” quite badly in any area where there are concentrations of alkali’s and/or acids in the atmosphere (even if the aluminium has been anodised to 35 microns, and not to mention “electrolysis”) whereas the carbon is unaffected, and there is the obvious advantage of the carbon, by being a “stronger” material, it can be made appreciably lighter than the same profile mast in aluminium. As a “moulded” or “spun” profile, the carbon can be strengthened or lightened wherever it is desired (personally tailored), an advantage that is extremely difficult to accomplish in aluminium. To our way of thinking the improvement of a carbon mast over an aluminium one is about the same as the improvement of an aluminium mast over a timber one. Its simply, new technology versus old.

I just got in from Singapore in the early hours of this morning. I met up with Scott McCook at Changi S C and managed an afternoons sailing of the new VWM Blade owned by David Adams - THANK YOU, David! First impressions are that it's a very good package, even 'straight out of the box'.

I'm going to take the opportunity, if people don't mind, to jot down some thoughts on the experience of this boat versus my own Stealth and my general impressions. I'll post later, after I've caught up with work, sleep, kids etc..

Darryll is refering mostly to other points then durability and that was the question.

Aswer the question of what effect UV and Weather has on properly anodised aluminium. Could an aluminium mast survive 30 years of beachside parking in the sun ? To my personal experience the answer is yes; I had a 1974 Prindle 16 that I sold in 2004. One that was parked 6 months at the time in the sun and sandstorms. Yes it had been degrading by the influence of acids and salt (the white spots) around the fittings but it didn't fail and wasn't about too.

Shall we put a carbon mast through the same measure of abuse ?

UV coating is all fine but it is only a method of slowing down UV degradation. Quite effectively I might add but slowing down over stopping notheless.

I've seen alu mast after being sandblasted in sandstorms for over 20 hours. On the lower part of the mast, the top layer of aluminium oxide was blown away but under the action of salt an new layer was formed. Now do this with a carbon mast. That UV protection layer will not grow back on its own, no matter what other people say.

No I don't think todays carbon masts are something other then durable, but alu wins out just the same in the long run.

Same with carbon beams or extually even more so.

Now if you trailer your boat all the time and can keep it out of the sunlight and weather then carbon mast will go on a very long time, possibly 30 years or more. It is not that carbon is fragile. It is just that whatever abuse to put it through alu will hold out longer.

Wouter

Okay, call me argumentative (what I am) but I just love to react to this :




Shouldn't this read "Can be superior" over "are superior" ?

I've seen my share of carbon duds. The fact that a certain technology has the potential to be better doesn't mean that it actually is better in its implementation.

One great example are the Taipans. There was a test platform of a Taipan 4.9 in 2000 with a Saarberg Carbon mast and a Goodall mainsail. This combo proved to be way inferiour then the old alu mast and mainsail. Mast was way to stiff for the sail while the old combo (alu) had over 10 years of development on it done.

Like with every new technology; it needs a good time of development (trail and error) to realize its theoretical potential. I personally see carbon masts in F16 as in their initial stages while the alu mast rig has now seen over 15 years of development by some very skilled sailmakers. You are not going to beat that alu development with the first series of carbon masts. In the future you may; but not straight away.





Were I am we keep the boats on the beach for 6 months. A couple of spring/autum sandstorms can do wonders with this protection layer. Once it is gone it is downhill. Correct me if I'm wrong but I think carbon mast owners overhere do repaint/recoat their masts every so and so period. In theory Darryll is correct but in practice some other happenings may well impact on it.






For one thing the alu superwing mast is one the most resistant masts I have ever seen. See other posts. It think carbon replacements need first proof that they can be better then that. I'm unwilling to conclude that they are just by looking at a single material property number. In addition, carbon much stonger than aluminium in a direct sense. It is alot stiffer and lighter by direct comparison and this means that carbon layup can by alot stronger PER GIVEN WEIGHT and stiffer. Most most equate this "stronger per given weigth" to just "stronger", but this is incorrect and can even be deceiving. The stiffness is not all together an advantage either.

For a mast sail combo to be trimmable, a big necessity on catamarans, the bending of the mast is needed to flatten the mainsail or to have the top bend away. With the stiffness of carbon this is directly impeded. The solution is to make carbon masts with a smaller cross section and thinner walls. The direct side effect of this is that the mast is intentionally put under higher stresses to result in more bending and thus the mast as a whole will be weaker then it could be when looking at the material properties themselfs.

In addition stiff materials really do not like sudden changes in loads. Many will call this impact. For a while there A-cat carbon masts would break when capsizing the boat at anything but very low speeds. The stiffness of the carbon prevented the mast from bending with the shock load like aluminium and taking the real punch out of the blow.

In my experience, and I really shocked a few alu masts in my past, The alu mast will takes any load, capsize or general shock load without bending. The elasticity of the superwind masts is such that they can bend really really far before permanently bend themselfs.

I have repaired an alu mast myself that was dented after a storm blew my over and it hit a gate with its upper part. It took out a big dent and afterwards tried to take out some small remaining curve in the top. Let me tell you we started out really gentle but quickly we had two adults bobbing up and down one the end of the mast with their full weight to get it to deform. The mast was bending by nearly 30 degrees downward, which is ALOT when you see it. So I really don't agree with "it will most times “bend”"





That is true, with aluminium you buy a new one. The fact that an Alu superwing mast can be had for less then 1000 Euro's will make this still cheaper then repairing a carbon mast that costed 3000 Euro's whne it was new. In fact I can break 3 alu masts before even arriving at the price that it would have costed me to get the first carbon mast. I'm still on my first alu mast though and in 9 years of sailing/racing catamarans I haven't broken a single alu mast.





Like I said my Prindle 16 had a 30 year old alu mast and race halve the time in 15 + knots winds.




This is not a durability issue. Also carbon mast NEEDS to be lighter as otherwise the mast will be FAR too stiff or the crosssection will be far to small.





This propertie is as good as impossible with aluminium. However this is also not a durability issue. In addition it takes quite well developped engineering skills to realize this potential into reality. I refer again to the case of the carbon masted taipan 4.9. The fact that this can be done doesn't mean that it will be done in reality. As far as I know even A-cat masts are only offered in three categories : flexible, medium and stiff. Correct me if I'm wrong but it is either too expensive or impractical to offer more variations. Get the wrong one for your crew and you are worse off or you'll have to have you mainsail recut to correct for it. Naturally, the last action can also be taken to correct a standard alu mast to your crew weight. With this the question becomes ; how much additional effect can be expected from a carbon mast, and is that worse an additional 2000 Euro's to you ?





Great one-liner but I'm sorry to say that I can't underline this statement. The major difference between timber and alu was that more general shapes and improved shapes were possible with alu then with the old techniques used for timber. This difference is not really present in the comparison with alu to carbon and so the difference between the latter two is alot smaller then the first two. In addition glue techniques have allowed timber masts to catch up again, something many are forgetting. Right now it is possible to make shaped and hollow timber masts using strips or plancks and glue. These are then routed into shape. They are quite lightweight and the bending characteritics can be engineered to quite a decent level.

Biggest advantage of aluminium was of course the costeffectiveness of production. A anodised extruded section can be had for such a small amount of money that the labour intensive timber mast production was simply not viable anymore. We musn't allow ourselfs to think that everything is driven by advances in performance.

Wouter

Like I said, that font doesn't work.

The other part I have already told you about in a private mail.

Wouter

Ohhh, I'm really looking forward to this.

Sadly haven't really sailed the Blade myself yet, while I did sail the Stealth F16 is 2 days worth of racing (6 heats).

Via others I know the comparison between the Taipans and Blades, but I'm anxious to learn of a direct comparison between the Stealth F16 and Blade F16. In private mails I've been asked about that quite a few times and I always had to answer that I really don't know.

John, I've send you a PM as well. Please read it.

Wouter

How about a Blade F16 with the Stealth F16 steering?

That is exactly the part where I'm interested in.

The two designers took a completely different approach here.

Stealth was fitted with T-foil rudders, an active element in the way of prevents hobbie horsing and dives and it definately works (personal experience)

Blade directed alot of attention to making the hulls very forgiving in this respect. Meaning that you can dive them under or rock them about without losing much speed at all and while being assured of full recovery. The redistibution of the volume should cut down on hobbie horsing.

Have both approaches resulted in the same net result or not ?

Would adding T-foils to the Blade make it better still or is that not needed anymore ?

Like I said I'm anxious to hear the comparison by someone who knows that Stealth design very well and thus can make a founded comparison.

Wouter

Ok, kids time for bed, Daddy has some reporting to do....can't wait.

OK guys here it is:

I must preface this ‘report’ with the statement that it is entirely subjective, and totally my personal opinion, based on just one afternoon’s sail in conditions and a sailing area that I have not sailed a Stealth in. There was no other Blade or Stealth around, at the time that we were afloat, with which to compare speed or behaviour, my views are therefore based entirely on experience and my best judgement. With this proviso in mind, please feel free to read into the following whatever you wish.

Boat: [color:"red"] VWM Blade F16 [/color] Sail No. [color:"red"] SIN 708
[/color]
Wind conditions: [color:"red"] 15 – 17 knots [/color]

Air Temp: [color:"red"] 31°C [/color] Sea state: [color:"red"] Moderate chop [/color]

Mast: [color:"red"] Superwing with Proctor spreaders [/color]

Main: [color:"red"] Ullman [/color] Jib: [color:"red"] Ullman [/color] Spinnaker: [color:"red"] Redhead [/color]

First impressions:

The boat is apparently well built with good quality fittings and beams, the trampoline area is relatively uncluttered with the important controls easily to hand. I particularly liked the ‘de riguer’ self-tacking jib track moulded mounts and the double sided jib sheet system (the Stealth has a single jib sheet). The mast rotation arm is centred via the trampoline with controls out to the side deck each side, whereas the Stealth has the more common boom mounted system. The sails, once up, looked very good with plenty of shape quickly available to either sail via the downhaul systems. I didn’t like the mainsail Cunningham though as there was insufficient travel available on the cascading 8:1 system. This was re-tied several times before launching but was still insufficient to properly flatten the main once on the water. The hulls are the main thing I was interested in though and Matt should be very proud of his product. Scott (McCook) tells me that the VWM stem is shorter at 410mm than the 450mm shown on Phil’s plans and as built by ProSail Asia into Agent Orange. This gives the VWM boat a slightly more aggressive look, but does it affect the boat’s performance? The hull finish is excellent and I could not fault the joints, beam trays or board trunks. Speaking of boards, I was amazed to see that the Stealth centreboards are almost double the depth of the Blade’s but around two thirds of the width! For my test sail this Blade was fitted with AHPC Taipan rudder blades as the owner was adapting the ones supplied by VWM. This may have had some repercussions on my test sail as I shall explain.

On the water:

I was fortunate that Scott agreed to crew for me as my wife had decided that the Changi S C swimming pool and sun loungers were more attractive than blasting around Serangoon Harbour on the end of a wire! We therefore set off at a brisk pace upwind with me out on the trapeze while Scott adjusted the mainsail cunningham and mast rotation (see earlier). Once we had established that the main was as good as we could achieve in the circumstances, Scott joined me out on the wire and we began to really push. The Blade slices easily upwind and feels like a much bigger boat. Whereas the Stealth will ‘bounce’ on the waves upwind due to its flat bottoms and relatively high buoyancy, the Blade handled the waves in a more cushioned but still very buoyant way. The sailing angle of both boats seems to be very much the same with the forefoot of the bow just out of the water, but the Blade seems to give a more comfortable ride. It was a shame that we did not have a Stealth with us to compare pace. There was a Taipan 4.9 F16 also out for a sail and the Blade was clearly faster. At this stage it became clear that we had an issue with the rudders not being parallel, the boat was sailing well enough, but occasionally the rudders would ‘lock out’ as I tried to play the waves. We continued though, as we were having a really good time in the building breeze. The Blade tacks every bit as well as the Stealth and carries its speed through the tacks – I was starting to really enjoy the ride and getting quite a good feel for the wave pattern. We started to really fly and Scott played some more with the mast rotation – the Blade seems to be more responsive/critical of mast rotation due to the Superwing – the Stealth uses a more pear shaped, tapered carbon mast and although it does, of course, respond well to correct rotation, it is more forgiving than the Superwing. I quite liked the Superwing mast, but I think I prefer my carbon tapered mast for this reason.

After a fair bit of this upwind work, we turned to try the spin. The kite was up very quickly and smoothly, the system is exactly the same on my Stealth with a single line hoist. First of all we heated things up with me out on the wire and Scott playing the kite from on the hull, the main was cleated in hard and I played the traveller. The Blade absolutely LOVES downwind! It’s not as solid downwind as the Stealth though, which (with its foiling rudders) simply picks up and drives with every gust. The Blade needs to be worked downwind to get the best out of it and (when you get it right) is very rewarding. The lee bow would occasionally bury but the boat simply shook it off and carried on. I was having some difficulty staying on the side of the boat with the rapid speed changes and no aft toeloop(s). A couple of times we nearly came a cropper as I left the boat and went waterskiing! We carried on and tried a few fast gybes, now though Scott was trapezing behind me and I stayed on the hull up against the rearbeam. The Blade is just as responsive as the Stealth, and the misaligned rudders were not a problem at lower manoeuvring speeds. At the higher powered-up-with-spinnaker speeds though the rudder issue was a bit more of a problem and within minutes I’d flipped the boat in one bearaway gust as the rudders locked out.

This now gave me a chance to see how much of a difference there might be between a carbon and an ali mast – I weigh about 70Kgs soaking wet (which I now was ) Scott is around 75Kgs I would guess, so the F16 should pop up real easy with our combined weights. In those conditions, on my own, I reckon to get the Stealth back up within a minute of putting the kite away. With the Blade, Scott quickly had the kite away, but the boat showed no sign of coming back up with just him on the righting line. I quickly got up onto the lower hull and then leaned on Scott. With our combined weight it still took probably more than a minute for the mast to ‘unstick’ but then only seconds after that for the Blade to pop back upright. Our pitchpole had been a biggie – we’d lost one centreplate (I recommend attaching the boards to the shrouds with a length of line and a caribine) and the tiller bar and extension! A quick sort-out and then we sailed a short distance upwind to collect the (floating) centreboard. A tack and we picked up the tiller bar. I should explain that, because of the borrowed rudders, the tiller bar had to be retained on the tillers by bungee. No breakages though, so some more sorting out and we set off again. We made some more distance to windward and I was again impressed with the smooth action upwind in the moderate chop. A couple of reaches for fun, fully powered up, with us both wiring and then we turned downwind again. This time I hiked the boat at the outset with Scott trapezing behind me and locked up against my back. With the boat heated up again we managed to surprise quite a few onlookers with the speed of the Blade downwind, incredible amounts of green water splashing across the trampoline, the lee bow disappearing and reappearing, and the boat barely slowing. It’s a much wetter ride than I’ve experienced on the Stealth, but fun! The Stealth tends to plane easier with its much flatter bottoms, it’s not as smooth a ride upwind but downwind I think it has the edge over the Blade – it’s predictable and I think you can push harder in strong breezes. That said, I still think the Blade is a superb boat that feels much bigger than an F16.

How much of the Stealth’s downwind strength is in it’s rudders is difficult to tell- the Blade and Stealth have very different hull bottoms. But, as already mentioned on the catsailor forum, I’d really like to try the Blade with John Pierce’s latest Stealth rudders.

Overall I’d say the Blade is probably a more comfortable boat upwind than the Stealth, the two boats seem to handle equally well and both have almost identical systems and gear. I also thought that torsionally the Blade is not as stiff as the Stealth and the hulls could be seen moving a lot in the chop upwind. This may well have helped the ride. The Stealth uses nice large 3 1/2" dia round beams as opposed to the smaller mast section beams on the Blade. The Stealth is, in my opinion, a stronger downwind boat and can be pushed harder than the Blade and in stronger breezes. I particularly am sold on the Stealth carbon mast, both for its lightness and its non-critical nature in terms of rotation.
Which boat would I buy given the choice? That’s a tough one! I think if it HAD to be the standard boat, it’d be the Stealth – just. My ideal though would probably be the Blade (because of it's looks and upwind ride) with a Stealth mast and rudders (if – as I suspect – the Stealth rudders are the real power behind the Stealth’s amazing downwind behaviour). For the moment though, I’m very happy with the boat I have.

Thanks alot John, just what I was looking for :

Your comparison seem to run parallel to that of Stealth vs Taipan for a long way.

A few quick comments :



What do you mean exactly by this. The hulls are less high ? Or just the very front part ?




Here too we see two entirely different design approaches. It appears that both work. Interesting.





That is a pitty. The rudder board profile as supplied by VWM is of a noticeable better section than the AHPC ones. You would have had full control at all manouvres with the other ones. I have the AHPC ones myself and while they are generally good sections, you can make them stall (lock-up) during some more extreme manouvres. Still it; appears you had more trouble with steerage then is normal for well alligned AHPC rudders.





After having raced the Stealth F16 in several day/heats I feel that no boat without T-foil rudders can feel as rock solid as the Stealth F16. You really can just ram the boat downwind and do your thing on the trampoline, the bows will simply not dig in no matter what. I don't know about the payback though (loss in speed ?) but I much rather loose some speed momentarily then risk a deep dive with possibly a capsize. I remember that during the race we eventually wouldn't even pay attention to the bow anymore. We would just round the bouy, get of the trapeze dive forward and start pulling the kite. This in itself is racing advantage in my book. On my Taipan we need to time the bear away and following actions with the movement of the bow section.

I'm absolutely convinced that the T-foil rudders are the reason for the solid feel of the Stealth. Besides John this is easy to test really. Just lend yourself a couple of daggerbaords of a fellow Stealth owners and slide this in your rudder stocks instead of the T-foil ones.





Yep, say no more, those are AHPC rudders alright.





A wild guess here : Your downhaul was on still tight and the top of the mast was hooking the water OR the wind = Standard Superwing behaviour and entirely preventable. The squaretop top is still standing up too much.

I've encountered this behaviour myself a few times. The rig is not cut loose enough. Run mainsheet traveller out (all the way) first, then run out as much mainsheet as there still is left, then completely slack the downhaul, possible running it out with your hand a little bit. THEN Shake the mast a little using rotation arm (mainsail will unjam herself in the mast). Now she will come up as expected. 10 seconds max. If not then release the outhaul (along the boom) as well and make sure the bolt rope is not jammed right about the goose neck.




There should be a system to raise the boards, this should also keep the boards on board during a capsize.




It is true then. Different design approach then usage of T-foil rudders but it works.




That may well be an excellent cross polination between the two designs.




I always thought the Stealth to feel much stiffer then one would expect by looking at the beams themselfs. I was surprised at that myself. I also suspect that SIN 708 can be made stiffer easily by having (halve) disk like inserts underneath the outer bolts, in both beams. See close-up of mainbeam. With this the walls of the beam are really jammed up between the inserts and the beamlanding and can't flex.







Thanks alot John,

I will from now one refer interested parties to this report.

Wouter

the STEM Wouter, the very front of the bow....



This boat had that mod and yet it still wasn't as apparently stiff as the Stealth. I suspect that it's more than just the beam section that Stealth use. It has a lot to do with the care that John Pierce takes with EACH beam tray he builds for every boat, the way that the striker plates fit into the trays, and the attention paid to the drilling/tapping of the bolt holes.

Great report John! Sounds like you had a good time on the water in Singapore.

A couple of questions to Wouter (I guess)

1: What track is that I see used for the selftacker in the picture (Ronstan?)

2: Why have they done the beam bolts that way? I am used to seeing the beam bolts go trough the whole beam, and compression pads inside the beams. I surmised this was the best setup for max. stiffness.

Thanks Rolf,
We had an absolute ball! BTW the Stealth beams are bolted the same way as in the picture. The method you describe is the one that has always been used by most of the T builders. (as well as other cat builders).
On my Stealth the bolts are Allen bolts with dished washers, but later Stealths have a shaped piece similar to those in the Blade picture.

Wouter

I can tell you that we extensively tested these rudders, we had the prototypes for over a year before we built a mould, and we tried them in 2 boat tuning runs against identical boats with non-t-foil rudders.

In light winds and medium winds on flat water we could see no difference in speed between the 2 set-ups, changing crews every few runs.

As soon as there was any waves, even in light winds the t-foils would start to pull away, consistantly.

As the wind increased the t-foil boat got quicker downwind regardless of waves, upwind the closer the chop the quicker the t-foils were, their upwind speed was related to nastiness of chop not wind strength.

I have to say that I only “skimmed” through Wouters “counter” reply to my earlier post on my opinion of carbon compared to aluminium, but I take it that he disagrees with it??
I did read his comparison of time effect on aluminium comparing it to a “theoretical” similar time exposure to carbon and on this I would like to point out that although his comparatives concern the “life” of the two different material masts, he is forgetting that most of the boats that any aluminium mast is standing up on when exposed for long periods of time, to the extremes of weather, are on FIBREGLASS boats. Now any fibre reinforced plastic (fibreglass) boat is constructed from the same basic materials as an FRP mast. The base resins may vary but the basic form and structure are the same, so if the aluminium mast stands up to years of exposure abuse I presume that the boat that the mast(s) are standing up on will disintegrate in a relative short time, IF, as Wouter intimates, the life of the FRP under weathering extremes is much less durable.
The resins in the laminates of every fibreglass boat will break down under the direct influence of UV exposure that is a feature of ALL resins. The only thing that protects the laminate resins from UV breakdown is the surface coating of either “gel coat” or some other “paint coating, but as we can see from FRP boats that have been in long service, some for over 50 years, the surface coatings work extremely well. Why should the life (through exposure) for a boat hull be any different from the life of a FRP mast with similar coating protection?

On the point of “impact” and “durability”, after much “experimentation” we have an internal laminate of 300gm/sqm Kevlar twill added in the lay up of our carbon masts from a point approx 450mm above the hound position to a point approx 1.5 metres below the hound position. This is the area “of greatest stress” when a mast is impacted when “ditched” hard and suddenly. Carbon masts that have failed in the past under these conditions have usually failed approximately 600 to 800mm below their hounds. They haven’t failed through any compression loads at that time, but if the fracture is inspected, it is found that the laminates have failed on the “tension” side of the mast (carbon is very strong under compression, not so much under tension). They have literally been “pulled apart”. By adding Kevlar (extremely strong under tension) to the mast over this area we have found that breaking a carbon mast, even under the most extreme “pitch pole” situation, just doesn’t happen.
Still when its all boiled down, “time will tell” and I personally feel that in a relatively few years when all these questions are fully answered, and the availability and price of carbon are not an issue, we will see as many boats with aluminium then as we do with timber now.