Can't find much related to rake of the spreaders.

I've noticed a few Mozzies of varying ages with masts with swept back spreaders pretty much in line with the rear edge of the mast and was wondering what benefits this has particularly when so much forward mast bend is induced with modern sails and downhaul tension. Is it better to have the spreaders raked back or better to have them set at 90 degrees to the mast ?

If anyone has has thoughts on the issue I'd appreciate them.

Regards,

Peter

The fore and aft position of the diamonds attachment at each end also has a big effect on what the diamonds do to the mast.

I think, in general, the lighter crews put the spreaders further back to allow more bend to flatten the sail. But the mast is rotated so that effect is not so straightforward.

As for how tight, or what is fast, Bob Wilson always says he keeps adjusting them until the boat feels right!

For what it is worth- here is my take on spreader rake after having to re-rig mine. I am assuming it generalizes beyond my boat.
The more spreader rake the more you can induce pre-bend which, in the end, depowers the rig. This can be adjusted with the diamond wire tension (if there is spreader rake, if they are 90 deg then you wouldn't be bending anything really). I was told to not use a significant amount of prebend because I sail with a heavy crew (less pre-bend= more power for heavy crew). I assume high-end sailors will adjust their diamond wire tension to suit the conditions. The problem I have with all of this is this- I have about 1.5 inches of spreader rake with diamond wire tension actually pretty loose at about 250-300lbs which induces about 1.5-2 inches of pre-bend (maybe the mast is shot, who knows). Now add a spin and everyone starts talking about diamond wire tension more (to limit the S-bend). If I torque my diamond wires more to try to prevent that s-bend then I will end up with a lot more pre-bend than is necessary. Add to this is the fact that tightening the downhaul induces more pre-bend (thus depowering more) but doesn't really limit the s-bend (I think).
Well, I hope this gives you some idea about spreader rake,etc. I think I have succeeded in confusing myself

From what I can gather from the feedback both on the forum and around the traps (Thanks Garry) the raked spreaders are used for lightweight crews to induce mast bend and flatten the sail, sloop rig to even out the loading from the jib and for the spinnaker rig again to counter mast bend loading. In that case I will stick with the 90 degree spreaders on my cat rigged Mozzie. Thanks for the feedback.

I,m resurecting this topic because I finally got my new spreaders from Goolwa Masts for my new mast section. <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" /> Now I'm wondering where should I position them ? I've measured a few Mozzies at the yacht club and they don't appear to have the speaders centred. Should they be set dead centre between the mountings ? <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" /> Would the ones I measured have been set up to allow for jib leach ?

Assuming I put the hounds at maximum height where is a good height for the upper diamond mounts to avoid the diamond wires touching the stays during mast rotation ?

Any advice would be appreciated ?

Regards,

Peter

Hi Peter,

placement of upper attachment of Diamond wires I have always just looked at where the stays will clear them when mast is rotated. Markings on old mast may give you a good guide, if Hound and Diamond wire fitting to mast use the same method.

As a matter of interest I have heard people say that getting them as close to the hound fitting as possible, is one of the reasons for using T ball terminals. As they are generaly lower profile than any other method I have seen.

I have always placed spreaders in the middle of the diamond wire attachment points, don't know why just seemed right. I haven't heard any reason for doing it any other way.

Along with my own masts I have helped Tim, Peter and Neil build masts. Having a swaging tool and large riveter I tend to attract these jobs. Pity you are not closer.

Regards Gary. <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />

Peter

I have just been through the process of moving my upper spreader mount as I had a lot of binding of the diamonds on my side stay wires. I measured a mast at my club and the spreader upper mount was 300mm below the hounds. This is from the eye of the hounds to the upper hole of the spreader wire retainer (Ronstan style). Now when I did mine to this dimension I still have a little binding downwind as my system compared to the one I measured is slightly different styles... a bummer as I thought I had cured the problem for good. I initially had binding so bad that upwind the spanner would not rotate past the rear of the centre case... not good. So anyway I would look at spacing the top of the spreader retainers around 350mm from the eye of the hounds. I will be replacing my mast next season and will re do at 350mm...

Hope this helps..

Gary,

Thanks for the feedback. What are T Ball terminals, are they specifically for diamond wires and where do you purchase them ?

Regards,

Peter

Tony,

Thanks for the info. What a bugger that you didn't fully solve the problem last time around. <img src="http://www.catsailor.com/forums/images/graemlins/frown.gif" alt="" />

I'll go and take some more dimensions from my existing mast and other dimensions I took from other Mozzies.

Regards,

Peter

Unfortunately you can't even assume that much!
The general rule is that if you are carrying a heavy crew then you should put the hounds high to give the top of the mast the most support. If you are light you would set the hounds lower to allow the mast top to flex more and depower the main more easily.
I am a light-to-middle-weight cat-rigged sailor (72kg) and my hounds are right in the middle of the allowed range. This setup was also used by Chris Boag sloop rigged, with a very light crew - they couldn't have been more than 115kg combined. I hope that helps!


As far as binding on the sidestays is concerned, the position of the diamond attachments fore-and-aft will also affect whether they catch.

Tee-balls are stainless fittings which are pressed on to the end of the wire. They just hang in a reinforced hole in the side of the mast, and are easily removable from the mast. You have to find a rigger/chandler with the hydraulic press to make them up, and the fittings are not cheap.

Peter

The system I measured was a T-Ball setup I believe... I didn't know the name until it was mentioned in this post but the diamond wires hook into a slot in the mast, I know that. The system is very low profile compared to what I used, which is the Ronstan RF43A mast tangs with drilled out top hole to fit a 1/4" bolt and locknut. Due to this extra height I still have a little binding... I never stopped to think it would bind even at this distance (300mm) from the hounds. At least next time I will test (somehow) before I drill and rivet things together. Oh well, upwind I now have more power... Downwind I just need to pull the spanner around a little.

Cheers and good luck.

Tony,

I did some calculations based on my measurements and found that my distance from the diamond wires to the hounds was 240 mm. Another one I calculated was 145 mm so I don't understand why yours at 300 mm foul with the stays. What are the width of your spreaders ? <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" /> My new spreader is 580 mm from centre to centre of the wire holes.

Regards,

Peter

Tim,

Thanks for the info. I'm 86 kg so I assume that I'd be at the top of the hounds margin. Is that a good assumption ?

As for Tee Ball and the re-inforcing fittings, are they a Ronstan product or should I just take the whole setup to a rigging supplier and avoid the hassle ?

Regards,

Peter

At 86kg it would be reasonable to put the hounds high (somwhere between the middle and the top of the range).

Ronstan and Riley make the fittings but they are not the only ones. Most chandlery shops will stock them and many have the machine to attach them to the wire.

I just looked in the Whitworths catalogue and they only seem to have balustrading fittings which they call "Roll Swage Terminals". These are way too cheap to risk using on a boat so I would avoid them.

The Ronstan ones may be overpriced but they are certainly very expensive. Last time I looked it was $60 for one terminal. In practice, for Mosquitos these fittings look neat but are not necessary at all.

The standard swaged ends with a thimble will do the job, and you can do them yourself for a fraction of the cost. The tang for the top-end diamond fitting will work ok as long as it's positioned right. If building a mast I would just leave the diamond tangs till last and then put the mast up with them sticky-taped on - then you can move them around until they work.

Just so everyone knows what we are talking about here's the fitting in question on my mast.



You can't see the hole that the TEE is hanging in because I've filled it with Sikaflex. This is a problem with T-ball fittings - you are left with a large hole in the mast which you have to seal like this.

The reasons T-balls get used are that they don't stretch like swaged ends so your wires that are built to millimetric accuracy will stay accurate. They also look neat (except for the Sikaflex).

You can see the scuff marks on my mast from the sidestays. They go right up to the diamond fitting, so it seems this one only just works. Interestingly though, the little bit of Sikaflex on the tip of the Tee-ball is still there so the sidestays seem to just miss the Tee-ball.

The bearing points of the hounds and the Tee-balls are 300mm apart.

Peter

How odd... I will do some measurements over the weekend and get back to you.

Cheers

Peter

As promised.. see attached pic.

Centre of hounds hole to eye of upper diamonds - 280mm.
Upper diamonds to spreaders - 2300mm.
Spreaders to lower diamonds - 2600mm.
Lower diamonds to top of beam - 150mm.
Spreaders are 580 centre to centre.

Cheers

Tony

Is your mast by any chance raked forward?

I just realised that would make the sidestays more likely to catch the diamond tangs.

There was a time when Mosquitos (particularly sloops) had their rigs raked forward. These days they are almost never set forward of vertical, and any boat with the centreboard cases at their maximum aft position would have the mast raked back. Some cat rigged Mozzies (like mine) have quite a lot of aft rake.

Try dropping the mast back and see if it still catches.

Tim

My mast is vertical.. no rake for or aft... tell a lie it is 1/2 degree forward as there is a 1/2 degree bend in the mast at the spreaders.. so the top of the mast is directly above the base with the spreaders being 20mm forward of this point, effectively being in a neutral position. When I bought the boat it was raked aft but I could not get the helm balanced until I took out the rake. So if I am reading you correctly... you are saying that due to the position of my centre cases requires a vertical mast to balance the boat therefore side stays may (in this case - do) catch. On newer boats the mast is able to be raked further aft again due to centre case positioning (max aft) and will not catch..??

A couple of questions...
1. How much free rotation should a mast have... 180 degrees? I now have approximately 120 until the side stays grab where as before I changed the upper diamond attachment point I reckon I had maybe 60 degrees.
2. If I do rake the mast to clear the side stays how then do I balance the helm?
3. How do you guys insert a pic directly into the post like you have done..?? I can attach but have never worked out how to attach direct in a post.

I will chuck the mast up today in a raked position and see how it looks...

Cheers

Tim

See attached. This pic was taken today with the mast at the 4th hole down on the stay adjuster which calculated out to just over 4 degrees. I normally have it in the top hole which is no rake. As you can see the diamond wire still binds a little. There was actually very little difference between the non raked and 4 degree rake. You can imagine the trouble I had when the diamond wires were in the upper position as shown.

I'm puzzled. <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" /> Are all Mozzies set up with this amount of hardware up the mast? Why would you have your trapezes on a sparate tang aft of the rotational axis of the mast? This is just placing an unecessary additional axial loading on the mast. Almost all cat masts that I know of have the stays set on the lowest hole of the hounds fitting and the traps on the highest hole. Sometimes people will split the stays and have the forestay on a separate shackle on the middle hole, but I've never seen a set-up such as this.

BTW. To add photos into your post:
1. Attach pic in the normal way
2. View your post, view attachment, copy URL from the address bar
3. Go back and edit your post
4. In the editing box, choose the point where you want to insert the pic with the cursor
5. Select 'Image' from the Instant UBB code section
6. Paste the URL into the dialogue box that appears and press enter
7. Preview your newly edited message and submit....

Tim,

Thanks for the info. I'll go in search of T ball fittings this week. I'll try to set up most of the system but leave the final positioning until the weekend and bring it along to play with at Hazelwood. <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />

Regards,

Peter

Tony,

Trouble !! <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" /> I don't see how the system worked when the diamonds were mounted above the hounds. As Jalani says the trapeze wires will be working against the natural mast rotation axis and inducing more stress. This is definitely not good. <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" /> <img src="http://www.catsailor.com/forums/images/graemlins/crazy.gif" alt="" />

The diamond wire mountings also look very bulky and appears to stick out too far from the mast. My existing mast has the swaging built into a Ronstan flat bar fitting that was then bent to allow just sufficient space for the swaging to contact the mast. The trouble with that is that you can't see the mast or clean it or see what corrosion has been progressing. I'll definitely be going for the T Ball fittings with my new mast.

Regards,

Peter

Hi Tony

Oh well there goes another theory!

The answers to your questions are:
1. I don't think many would go 180 degrees in the boat park but when you are going downwind in pressure and the leeward sidestay goes loose the mast may get around that far. It depends on your mainsheet/boom setup and whether you are using a vang (rotation inducer) or not, and on the amount of rig tension (lots will limit the rotation).

2. If you have too much weather helm going to windward then you probably can't rake the mast back. Lifting the centreboards or using smaller ones would help but if your cases are not in the maximum aft position this will only make a small difference.

If you can get 120 degrees now, that may be enough.

Hi John

I think many used to be like this but these days new masts usually have just the stainless tang with two holes as you describe.

I think that the rigging and fitting layouts of most non-SMOD classes have got a lot simpler over the years.

Jalani

Yes this mast is hardware central... unfortuneately the way it was when I bought the boat. The mast only has another season in it due to a lot of corrosion in the base and the mast is actually bent rearwards by 20mm when the diamonds are released.

The odd setup in my earlier pic you added to your post was only done today as an attempt to clear the side stays. I normally run the side stays in the bottom hole and the for stay in the top hole as in the attached pic.



Yay it worked.... cheers.

Another point to mention is the hounds that are on my mast are no longer made so god knows how old this mast actually is..??

Peter

You can only imagine.. not very well. Most people hang the trap off the hounds which I think I will do to help with rotation...

Yes there is a lot of unnecessary bulky hardware which will go once I replace the mast.. I will probably end up with this T-Ball method. The simpler the better in my opinion. You will have to let me know how you go with yours...

Whoever initially put this mast together didn't put much thought into it... and I am certainly no expert. This is where this forum is so great.

Cheers

Tim

Thats ok, it was worth trying... and if nothing else all this talk and pics is showing Peter and anyone else how 'not' to assemble a mast, lol.

I realise that the masts rotate with pressure but didn't know how much free rotation a mast should have when not under load (on the beach, no sail)... Even with the little binding I have now I think I will be fine for this season at least. Then its mast replacement time.

I really like the feel of the boat now with no rake.. and I am 92Kgs at the moment so I need all the power I can get, hehehe so I certainly don't want to rake the mast... and as I found out really has little affect on the binding anyway.. thats why in the first pic I put the side stays in the top hounds hole to see if that would help.

Thanks for the help..

Actually I have a very similar hounds fitting on my "new" mast (built earlier this year). The fitting is made by AHPC. It only has two holes and looks like a heavier guage of stainless but otherwise is the same.

For a while Mozzies were using the A-class style fitting that sits inside the mast with just the tang coming out through the mast. This looks very neat indeed, but a Taipan, in the states I believe, tore the stays shackle right through the fitting and when I asked for one AHPC told me they didn't recommend them for sloop rigged boats any more. So now they sell a fitting that looks just like the one you have.

Tim

Yeh, mine is an old Ronstan, model number RF1 which is no longer listed in their catalog. It is fairly flimsy as there are some pretty impressive bends in it from the D shackles twisting it. A friend of mine has just built a mast using the tang through a hole idea.. looks neat I must say. According to my calculations I still have around 50mm left in the hounds attachment range so I may be able to re-attach the hounds 50mm further up the mast therefore clearing the diamonds completely, this would also be worth doing as I am 92Kg. My only worry is a lot of holes in the mast where the loading is the most. I could patch it I guess... any thoughts..

Cheers

Tony, provided the holes in the extrusion (once the fittings are removed) are perfectly round and there is no sign of cracking or tearing, you should be able to simply plug each one with a blind rivet of the correct size with no real reduction in structural integrity of the mast. Don't forget to use good quality aluminium rivets as they are only being used to plug the holes. It would still do no harm to use an insulating paste though.

Hey its Ben from sydney. Can i buy a new mast section in sydney For my mozzie?

I have just gone through the process of getting a new mast in Brisbane. It was going to be too hard to transport an 8m extrusion from the association in Melbourne so I hunted around for something else and found that the Calypso cat supplier had them also. I think it was a calypso 14 mast section. Just check the dimensions before purchasing. From memory, it was significantly more expensive than purchasing from the association, but considering no transport companies wanted to touch it, it was the only option for a new mast.

Does anyone know who manufactures the extrusion?

I deal with most aluminium producers in my job... If it is Capral who make the extrusion it will be produced in Queensland and their road transort system takes it through Sydney to Melbourne then onto Adelaide. The only worry I have is their max lengths are usually 6.5m not 8m, this may cause issues, hence the trouble nickb had. Also they may only produce masts for the association once in a blue moon and will probably not have any in stock.

You may be able to arrange something through Capral if they are the manufacturer and have stock that is... if not then nickb's option may be the go. I would contact the National Association and talk to them regardless. I am sure they have shipped masts around the country before.

I have called capral, onesteel and smorgons, all played dumb when it came to mast sections and knew nothing about them. I suspect I was talking to the wrong ppl or the dies are owned by other companies and hence not available to the general public.

Nickb/Ben

I have contacted the South Australian Mosquito Association to see if anyone knows where these masts come from and who owns the dies. In the meantime I will call the people at Crane Aluminium and Capral that I know and see what I can find out. Unless I have the profile/extrusion number I may not get far!!!

Peter/Jalani/Tim
I have remounted my trapeze wires on the top hole of the hounds so as not to fight against mast rotation, thanks for all the input, its been a good topic this one.

Cheers

Tim
Is this the one (F16)... $66 from AHPC. Looks like it will work a treat..



Cheers

Hi all,

couldn't agree more excellent post. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" /> I wish this forum was around when I bought my first Mossie,mind you I didn't have a computer LOL. Certainly would have saved me some time, as I was the only active boat in the area at the time and had nobody to talk to, but the rigging tuning guide was very useful.

My first Mossie sail number 1111, mast was covered with hardware and filled with foam <img src="http://www.catsailor.com/forums/images/graemlins/crazy.gif" alt="" />, it took two people to lift it upright <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />. It was one of the best upgrades I did for the old girl she hadn't been raced competitvly for years and it is weird what some people do to an old Mossie, if they don't seek help within the class. I would highly recomend this upgrade for any of the realy old Mossies, as it is one of the cheapest performance improvements you can make, buying of the Assoc. that is.

As far as getting sections don't go racing off reinventing the wheel, my recollection is that some major negotiations had to be done recently regarding, Dies, Joblots and Manafacturers, Capral rings a bell. I am sure Tim can come up with the info from Philip W/S as I think he did at least some of the work if not all. So hang five and should have the facts of the situation soon, another thing we can discuss at Hazelwood tuning this weekend <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />.

Regards Gary. <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />

Hi Tony,

the rake you describe sounds very familiar, I am also 90kg. and found myself sailing with little rake on my boats, none of which had the centreboards back to the max. The main thing is the boat feels sweet and balanced, regardless of rake it will be fast in strong winds with our weight.

Regards Gary. <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />

Guys

As promised this is hot off the press from the secretary of the South Aussie Mozzie Association.. wow that ryhms, hehehe, oh its been a long day.... anyway here it is.

Gary

Yes I have only just got it balanced to the point where it now feels really nice and sweet, not to much pressure on the blades etc, and doesn't round up at the drop of a hat (or tiller), hehe. I have had her out in 22kts and we went quite well considering the lack of skill, lol... lots of downhaul and away we went skipping from wave top to wave top, nah... that is the only time us big guys have one on the little whippets... 20+kts.

Cheers

Yep that's it. A very solid piece of hardware!

Hi Ben

I have an idea how you may be able to get a mast. I'll email you tonight.
Are you still wanting a mainsail as well?

Hi Tim i have my mainsail at the sail maker getting a few small tears repaired. He is actually the guy that made the sail a long time ago. The sail seemed very flat so he suggested that i soften the batterns. I'll Give this a go but im sure that if someone has a good second hand sail i would be interested. It was ok up wind but suffred down wind then that may be angles or driver error. Its a shame melborne is so far away. I was that close to making the trip for this weekend.It would be great just to check out what everyones doing.(ps if it was between a new main or a spiniker it wouldent be a hard choice! That would solve most of my down wind problems.

Tony,

Thanks for the info on the hound fitting. <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" /> I've been looking for this setup for ages and every time I go into a chandlery or rigging place they just look confused <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" /> and go through the same old fitting catalogues again. <img src="http://www.catsailor.com/forums/images/graemlins/mad.gif" alt="" /> I ordered it today so maybe I'll have it on Friday for the weekend.

Regards,

Peter

Peter

No worries, happy to help, it was actually Tim who lead me to that particular one. AHPC did mention that they would have to re-curve the hounds to suit the mozzie mast which would not be a problem. Did they mention that to you at all?

Cheers

Tony,

No they didn't mention about re-curving the hound but I did ask for the hound to suit the Mozzie so it's fingers crossed for now. They even sent a reply asking if I was cat or sloop rigged. Maybe they have a heavier grade stainless for sloop rigged or maybe the trapeze hole is larger.

Regards,

Peter

Peter

I'm sure you'll be right if you have told them its for a mozzie. Anyway this is the email I got from them regarding rebending...FYI



Good luck... Oh, have you got a spinnaker on your mozzie yet?

Tony,

No, its one thing at a time for me and the biggest thing at the moment is getting the new mast set up for the season (new hound, new spreaders, new base, new halyard fitting, new wires) Hey practically new everything. <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" /> Apart from that I don't know if the old Mozzie timber hulls could cope with the added stresses induced by a spinnaker.

Regards,

Peter

Peter

Yeh.. know the feeling... I had a call from one of the association guys last night to tell me we have approximately 8 masts available at $250ea.. Can't argue with that, so I will get one in the next few months and refit it at the end of the season.

Spinnakers, hmmmm.... there is no way I have enough experience or skill "yet"... but give me a couple of seasons and I will be keen as mustard...

Gonna be a great weekend (Tomorrow 24 degree's/8-13kts) and (Sunday Winter Series Race 27 degree's/15kts) My wife said I should sail both days..I got a great wife <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" /> or maybe she just wants to get rid of me..lol.

Cheers

Tony,

Your wife is really good to you or she just wants to go shopping with the girls because you're out having fun. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Measured a few masts at the training weekend here and found that to get complete clearance you need to have 310 mm from the centre of the lower hole on the AHPC hound to the centre of the Tee ball where it comes out of the mast. So much for my 240 mm estimate!! <img src="http://www.catsailor.com/forums/images/graemlins/mad.gif" alt="" /> Well, at least the diamond wires were made too long and not too short so it's back to the riggers tomorrow to have the wires cut and new lower terminals swaged with minimal damage to the hip pocket.

I also learnt from the guys here that if you put a knot in some spare 5mm shock cord then feed the Tee Ball re-inforcing plate onto the cord, feed both through the slotted hole in the mast then once the plate is rivetted on all you do is pull the knot back out through the hole. So simple and neat <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />.

Regards,

Peter

Peter

Yes she is a special girl thats for sure...

310mm cool, well now at least you know for sure and you can complete your mast. I checked my rotation upwind yesterday in 15+kts and if I release the rotation limiter the spanner swings around almost in line with the beam... can ask for more than that.

Thats a neat trick which will make life easier for you..

Cheers mate..