V3- Early sketches

So, here we go again, I might listen this time, then again I might not. My plan this go round is for something to play both on the lake and on the sea, something that doesn't keep falling over, doesn't do that tedious death roll business offwind and if it does, something that I can at least get back into with not too much trouble.
I also have a decent sized man cave that SWMBO has not converted into a lodging house for 'friends' of the daughters of darkness and the necessary tools for a bit of wood bothering.

Other than building that ill fated 'water pusher' a sort of cat sled thing for speedweek, I've not done a lot with Ply. I've got that Gougeon Bros book somewhere, but I don't fancy glue, I'm thinking plastic nails then seal the joints with epoxy glass.

My thinking is 5mm ply for the key stress bits, keels, tansom, shape formers, then 3 mm everywhere else.

As you can probably just make out from some of the sketches here, the idea once again is for a central hull to support the rig and forward rig loads, then aft of that two narrow canoe style hulls designed to come into play upwind as it heels, so you get really narrow upwind, then offwind they keep it stable kind of a sailing trike.

Wash through, unstayed rig, the lever thing might or might not get built but I want to rake the rig and I'd like to try it windsurf style from the base using the upper deck as a pivot point hence it needing to be quite tall. I'll probably just amend the EPS rig to fit it for openers, what I'd really like would be a D0 rig, but first I've got to build the bloody thing from scratch and I dare say make stuff up as I go along.

My first move will probably be to cut keels using the rocker profile off various boards I still have access to, then I'll cut the transom and formers, build a skeleton then cover it.

Easier said than done, but with the Christmas break coming up and a couple of weeks kicking my heels I thought nows as good a time as any to have a crack.

Please feel free to point out the many pit falls ahead or any obvious things I've missed (like last time accurately pointing out I'd never get it back up alone if it went over), I'm hoping that by leaving the ends open and not having too much flotation in the sides this time they'll sink a bit more, I haven't done my volume calculations yet. Overall dimensions, the front hull will probably end up just over 2 mtrs and the rear bits nearer 3 with a metre overlap so overall length will pitch up around 4.20-30 and 1-65-1.85 wide depending on what it 'looks' like spaced out on the floor.

Here are some of the dozens of sketches that change everytime I do them but it's probably going to end up like this as near as dammit.





Edited by iGRF - 05 Dec 14 at 10:15am

...... Please feel free to point out the many pit falls ahead or any obvious things I've missed

You always learn something from 'doing' rather than 'talking' so good luck whatever the outcome - it is only ever a very small minority these days that 'do' in the real world rather than 'advise' via keyboard.  

One key to weight lowering is to keep the total surface area (deck and hull) to the absolute minimum.   That is one of the reasons why so many 'modern' boats arguably have a bit too much buoyancy  - if you 'deck in' as much as possible you reduce overall surface area.   Compromise decisions are needed.

I'd go with knock-back foils for a number of reasons - weed problems, launching, recovery plus the ability to move lateral resistance backwards when wanted.   It also can compliment a raked rig if that is also what you want - but personal choice on these sort of things as ever.   

Rupert is right about torturing ply and you will never get proper compound curves where you might need them...

Anyway - lets see the pictures as and when !

Mike L.  

I did consider cutting up a couple of kayaks I have lingering in the warehouse as the twin hulls, but these are the bits that will give the windward performance so I'm inclined to the view that I want the sides quite parallel and will curve the inner surfaces if anything to better deal with any residual bow waves in the internal channel.

The whole point is for kick back centreboard, slot flusher free and with twin rears it can go all the way up on windy reaches. One of the designs linked chines off the forward hull to the rears so heeled it were more efficient I shall still try for that once it starts to take shape, all that hiking nonsense better to design the boat so the more it heels the less surface area it presents, I did also consider windward canting rig with my lever device fashioned as a joystick via side to side as well as fore and aft pulleys but I doubt it would overcome the loads.

I know weight is going to be my enemy and will drill everything and leave out stuff that isn't necessary, if it works i can always use it as a plug to take a mould from, it probably won't happen, I know me, I shall be fed up and on to something else before that ever happens, but I'd like to make one at least, see where it takes me.

Curves how do they deal with that? Segmented strips?

Edited by iGRF - 05 Dec 14 at 11:57am

Can't help but think that you might be better doing away with the central "pod", but if you do have the central pod, should you raise the outriggers to ensure that you have one out of the water at all times,, reducing wetted area.

It's essentially a Vortex isn't it?