Formula 40 singlehanded trimaran build log

[Doug Lord]

Originally Posted by Silver Raven

Gooday Doug. Yes - c/b's in amas - way forward & also the wing is raked aft a considerable distance (that's always been my preference - for several reasons). I also not the the foren-sail is very very large & quite long on the foot - effecting the balance & necessity for the foils to be so far forward. Yes/no ???

Great pic - for this discussion - thanks mate. Ciao, james

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Remember James-they didn't sail with that jib too often-they pulled it down part way up the windward leg, if I remember correctly.

[Gary Baigent]

Doug, Dogzilla had to have the board/lifting foils forward, otherwise she would have rocked her nose in.
What is interesting is that when they really wanted to crank upweather of Alinghi in first race, for some time the headsail was dropped ... and upwind the Godzilla went, just ate Alinghi, remember that? So, from my experience on (imbalanced?) forward positioned foils/dagger, once you're set up on one tack, rig setup and trimmed properly (imo, slightly eased traveller position) the boat will go to windward like proverbial witch.
Would like to hear what James Spit has to say about helm feel at that time, didn't appear to be sawing downhill with the wheel. The difference with multihulls as compared to monos, is that there is greater leeway (no pun) with the former in terms of board positioning, and in Godzilla's case, (really a widely spaced catamaran) those widely spaced dagger/foils allowed some cheating of conventional rig/balance thought, platform pivot being way out to leeward. Of course tacking with same (no headsail) is not so easy (because boat wants to go into and stay in irons) and requires some neat timing with mainsheet easing as you go through the eye of the wind. Easier with headsail up.

[Gary Baigent]

Warwick, I wasn't criticizing you - although I think the dreaded words lee helm was not quite what you meant to say. Figured you meant to say a light balanced helm as compared to hard nosed weather helm. Cheers.

[Silver Raven]

Originally Posted by Gary Baigent

Doug, Dogzilla had to have the board/lifting foils forward, otherwise she would have rocked her nose in.
What is interesting is that when they really wanted to crank upweather of Alinghi in first race, for some time the headsail was dropped ... and upwind the Godzilla went, just ate Alinghi, remember that? So, from my experience on (imbalanced?) forward positioned foils/dagger, once you're set up on one tack, rig setup and trimmed properly (imo, slightly eased traveller position) the boat will go to windward like proverbial witch.
Would like to hear what James Spit has to say about helm feel at that time, didn't appear to be sawing downhill with the wheel. The difference with multihulls as compared to monos, is that there is greater leeway (no pun) with the former in terms of board positioning, and in Godzilla's case, (really a widely spaced catamaran) those widely spaced dagger/foils allowed some cheating of conventional rig/balance thought, platform pivot being way out to leeward. Of course tacking with same (no headsail) is not so easy (because boat wants to go into and stay in irons) and requires some neat timing with mainsheet easing as you go through the eye of the wind. Easier with headsail up.

Gooday Gary. Great comments & observations. A tad 'deep' for me this am - as I'm still trying to learn how to breath - all over again.

I'm at a loss to understand - why a multihull without a front-sail is easier to tack that a una rig - regardless of wing or not wing. I've never experienced being slower to tack in either 'A' or 'B' class - with & without wing masts ??? Suggest it's a tactic & a skipper problem - is it not ??? Yes/no ???

I don't recall (how convenient of me) that we ever lost out in a tacking duel to a Tornado in the 5 years we sailed against the best Tornado's in OZ. I really can't see what other people perceive as a problem ??? Please explain ??? Thanks blokes. Thankss for the observations Doug. Ciao all, james

[warwick]

That OK Gary, I think I could have worded my comment as to helm balance better.
I think it was James who mentioned preferred helm balance, thanks also.

[Gary Baigent]

James, talking about multihulls with FORWARD placed daggers/foils - where supposedly the boat is out of balance, weather helm tendency.
And going back to A, B Class cats with una rigs, their boards (as one of the basis's of this thread) have their boards set further aft than is conventionally thought to be correct (for headsail and mainsail rigs), hence they tack rapidly without going into irons, as the forward setups tend to do. The difference is that forward of CLR foils have to be in that position ... to lift the front end of the boat out. That is their raison d'etre (reason for existence). Cheers.
Try breathing yer Aussie crushed eucalyptus leaves, even Kiwis know that works.

[Corley]

Well this project has suffered the usual problems that appear to slow you down. The daggerboard being built by Ben is just about done and he is going to construct the daggerboard case and kickup rudder stock as well.

I dropped several plan pages off to a local stainless/aluminium fabricator and made the mistake of not taking copies. I've been on their case for nearly a year and each time they promised that they were on track. I went past their shop today after calling and getting no response they are closed the office cleaned out with no forwarding address and the factory for lease.

I'm having to purchase new copies of the missing pages from Kurt most frustrating. It baffles me why a company would choose to take on a job they dont want or are unable to do. If anyone has any recommendations for a fabricator that can be trusted to handle marine work and interpret plans in Australia I'd be interested to hear on this thread or via pm.

I've also done a power study and have found that between solar, wind generator and fuel cell I should be able to easily meet the power requirements for the boat while not loading too much weight onboard. I'm required by race rules in the event I want to enter to have an internal combustion engine of some sort I'll probably just use a minimum longshaft outboard mounted on a bracket on the rear beam like Kurt's original F40 tri carried.

[catsketcher]

Why go stainless or alloy Corley? There are almost no parts on a boat nowadays that won't be better in composite. Although it is more work for you it also saves money so things like chainplates, rudder boxes, rudder gudgeons, pintles, stanchion bases, sheave boxes have all been made from glass, glass tube and unis on my cats. It is really nice to get rid of the bolts so don't worry about contractors and glue and then stitch the fittings on.

I have used stitching unis to hold on my motor pod on Kankama and it has worked very well. Stitching also holds on all of my hinges for the mechanism of my folder. So sod the fabricator and get some tube from Exel composites in Brisbane and glue and glass everything you can.

cheers

Phil

[Corley]

There are not that many metal parts on the boat for example all the steering/tiller parts are carbon fibre layups. It really only uses stainless for chainplates and aluminium for the mast step. I agree that composite chainplates are great but I'm inclined to build the boat as much to plan as possible and revisit some areas when done. Another option might be titanium for the chainplates it's approaching affordable and eliminates some of the stainless issues. It's not going to have a deluxe interior so later access and retrofitting of composites chainplates will be quite easy.

[catsketcher]

Really Corley the chainplates are easy in composite. I understand the mast step (I have seen people use stainless trailer hitches) but chainplates should be composite. You will have much better load distribution, no hard spots, lighter weight, no holes to leak and no holes to rot. I don't think any designer today should be offering stainless chainplates for amateur building. Stainless chainplates will mark your boat as backward when new.

You can do the sizing yourself. Wire size for breaking strain. Increase this by fudge factor one - Skenes says 3 times for chainplates. Then look up data on carbon or S or E glass laminates and keep the strain down to prevent microcracking (Fudge factor two) Keep it down to 0.2% with Epoxy and you're laughing -

http://www.netcomposites.com/guide/micro-cracking/14

Work out the cross section area needed P=F/A to get the amount of laminate. Glue a glass tube on (leave it 40mm above the deck so you can easily get you turnbuckle to fit) and then wrap around it and down your laminate. As for length of laminate you want a nice smooth stress distribution so radiate them out and make some up to almost the same length as the reinforcing on the stainless chainplate. We even once cut the ends of each uni at an angle to reduce stress at the ends. Then cover the lot (when wet) with 600gm db.

Much better, lighter, sexier, modern, cheaper than stainless. DON"T DO THE STAINLESS!

cheers

Phil

[groper]

I agree with catsketcher.... and it doesnt take much effort to do chainplates in glass or carbon... your asking for trouble anywhere in the boat you have bolts and fasteners...

[Corley]

Thanks for the advice and link Phil and Groper, composite it is.

[groper]

I buy 1000gsm x 100mm wide Uni directional tape from atl composites gold coast. interleave this every third layer with 450gsm dbias tape as you build the total cross sectional area you require for the design load which helps keep the UD fibres in column. Im sure a quick email to kurt and he can give you the design for the chainplates in composite, i think most of his designs use composite chainplates anyway dont they???

[Corley]

Originally Posted by groper

I buy 1000gsm x 100mm wide Uni directional tape from atl composites gold coast. interleave this every third layer with 450gsm dbias tape as you build the total cross sectional area you require for the design load which helps keep the UD fibres in column. Im sure a quick email to kurt and he can give you the design for the chainplates in composite, i think most of his designs use composite chainplates anyway dont they???

This is one of his earlier designs but plenty of the later ones use composite chainplates with much higher loads than in this situation so it should not be a problem.

[rob denney]

Originally Posted by groper

I buy 1000gsm x 100mm wide Uni directional tape from atl composites gold coast. interleave this every third layer with 450gsm dbias tape as you build the total cross sectional area you require for the design load which helps keep the UD fibres in column. Im sure a quick email to kurt and he can give you the design for the chainplates in composite, i think most of his designs use composite chainplates anyway dont they???

Heavy carbon tow is more versatile than the heavy uni. And cheaper at $50/kg.

Corley, If you are thinking electric, check out the 18m proa down at St Kilda. 2 electric motors, weighs and costs the same as the 60 hp outboard it replaces. 2 hours of sun to fully recharge the batteries.

A foam/carbon mast wil be lighter, and arguably easier to build than a ply/carbon one

rob