4.75m Trimaran Project

5 year thread, 15 seconds of hippity hop "foiling"

 

Hiking board, sliding board designs; here is a famous one for you, Doug, thought you would have known all about them, you being fixated with wide leverage designs; this is International Canoe, originally designed in first half of last Century.
There is also Jack Holt's Hornet from the 1950s, and going back way earlier, the 19th Century Chesapeake log Canoe - also there are the Bermudian open boats that have a number of crew perched out to windward on a long sliding board, still racing today. Plus ca change, eh?

 

The original (Cunningham designed?) Quick Cat had a hiking plank. I can recall one of my fathers friends had a beautifully built ply example which I admired greatly. To be honest the plank system looked pretty unwieldy compared to a trap harness.

 

Thank you very much for your explanation, litle accurate, just to give a summary opinion. I guess at the total RM also have to consider the righting moment due to the hull. What do you think?. You are considering a position that, in practice, never occurs. I guess you know that the RM, you seem to indicate, it is variable according to changes the heel of the boat.
As for the distance, what happens if the ship is heeled ?. The distance is measured from a point or from an axis?. May be Gonzo could help you with the right answer.
But this thread is referring to other things, so I will not continue along this path.
I fully support the views of Gary Baigent.
Cheers

 

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You really are incredible! Your pompous rudeness drove the original poster off this thread!!!!! I've tried to answer questions and contribute but you continue with your rude, crude, uninformed(in the case of small tri's) silly comments and you accuse me of wrecking "another interesting thread"?
Amazing!

 

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Not even close to the RM of a small oversquare foiler tri.

 

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Thanks, Corely. Any pictures?

 

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TANSL,are you saying that Bethwaites illustration of max RM on an Aussie 18 is wrong? It's a well proven fact that high performance planing dinghies-particularly ones that plane upwind-sail faster flat or nearly flat. On a planing monohull dinghy, sailed that way, the hull shape and hull/rig weight have little to no effect on Righting Moment. The boats being discussed are relatively small dinghies that achieve stability primarily thru crew weight moved to windward of the center of buoyancy and/or center of planing lift.
On an oversquare trimaran, the crew weight moves further from the lee ama center of lift(foiler) and therefore has much greater Righting moment for the same weight. And on an oversquare tri, flying the main hull, the total weight of the hulls and rig adds substantially to the righting moment because the boat CG(center of gravity) is located far to windward of the lee ama center of lift. These are concrete facts, not guesses or speculation.

 

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ozfred, my test model is an example of a small foiler tri designed with an oversquare platform and serves as an illustration of the RM possible with that configuration(in answer to gonzo's question).

 

Gary, Oz,

While I agree with you, please just "ignore" him.

You guys are keeping this going.
He's proved he won't do what you want, and there are no rules which should stop him.
Of course, he has the same right to post as you do, so you can only control your actions.

I ignored him about 2 years ago, and except for your reaction it has been pleasant not seeing his posts.

 

I'm an occasional reader here. And while I agree with Gary, I think he picked the wrong thread for this discussion. Because in the long opening post, it is stated a clear intention of foiling. It is in several paragraphs. So nothing Doug wrote was actually off topic in this thread. But it has been in many other threads.

I think that the problem with Doug is not that he posts about foiling, but that he expects everyone to be, a gold fish.

 

Sensible advice from you two - and as said before I should know better than to attempt communication, albeit with some rudeness (necessay for penetration?) but also, I hope, a little humour - which of course, is totally lost on a frothing from mouth and ears absolutist.
Going back to Kaymaran asking advice regarding his 4.75m; his clearly defined list is obviously searching for comment and the "unmentionable" subject comes a long way down that list. The unmentionables appear to be (and they are) of less importance than that of getting the original platform into existance.
Walk first before you sprint. Not sprint in fantasyland before you build in reality??
There is nothing really special about the said unmentionables, one just has to take into consideration the requirement of extra layers of carbon to handle the unmentionables developing higher loads upon the platform structure.
Also Kaymaran specifically wants a simple to operate trimaran and does not want a ridiculously (and heavy as well as cumbersome) way oversquare and complicated design.
Maybe, and here be laughter, Kaymaran might check out the simple transporting solution of my 6.5m unmentionable.

 

If the basic basic boat is not laid out from the get go as a foiler then there will be a lot of needless surgery to rebuild it at the "right" time-if that's even possible. Makes no sense to ignore the requirements of the foils now and just think about them later. Planning ahead seems like good common sense not needless complication. Too bad you had to chase him off...but I bet he'll work it out-even without your "humor" and advisory rudeness.

 

I've often wondered about the viability of making a two part hull for a multihull split in the middle somewhat like a nesting dinghy. That way you could have a longer hull without having too much bulk to deal with and store. They added a 5' scoop onto the back of the AC45. It would be an engineering challenge but not an insurmountable one on a small multihull.

 

I've not been able to find any pictures but it was pretty low tech basically a plank that protruded from the edge of the boat that you lay on. I cant recall how it was attached now even though I can picture the boat clearly in my mind.

Carbon fibre would be a natural fit to the building a hiking plank these days as it would be deflection driven part and you could save some weight there. The boat was lovely varnished ply with mahoghany trim and well executed joinery throughout.