New Posts New Posts RSS Feed: V3- Early sketches
  FAQ FAQ  Forum Search   Register Register  Login Login

V3- Early sketches

 Post Reply Post Reply Page  123 7>
Author
iGRF View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 07 Mar 11
Location: Hythe
Online Status: Offline
Posts: 6499
Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Topic: V3- Early sketches
    Posted: 05 Dec 14 at 10:00am
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
Back to Top
Rupert View Drop Down
Really should get out more
Really should get out more


Joined: 11 Aug 04
Location: Whitefriars sc
Online Status: Offline
Posts: 8956
Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 10:57am
I like the concept, but I can't see how a boat with so many complex shapes is going to come out light weight - just too much surface area for the volume. Some really hard shapes to create from plywood, too.
Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686
Back to Top
blaze720 View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 28 Sep 05
Location: United Kingdom
Online Status: Offline
Posts: 1635
Post Options Post Options   Quote blaze720 Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 11:19am
...... 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.  
Back to Top
JohnJack View Drop Down
Far too distracted from work
Far too distracted from work


Joined: 12 Mar 13
Online Status: Offline
Posts: 246
Post Options Post Options   Quote JohnJack Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 11:39am
Bit like an IC with outriggers?
Back to Top
iGRF View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 07 Mar 11
Location: Hythe
Online Status: Offline
Posts: 6499
Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 11:54am
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
Back to Top
kneewrecker View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 09 Apr 14
Online Status: Offline
Posts: 1586
Post Options Post Options   Quote kneewrecker Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 12:01pm
Originally posted by iGRF

Curves how do they deal with that? Segmented strips?

clinker.
Back to Top
davidyacht View Drop Down
Really should get out more
Really should get out more


Joined: 29 Mar 05
Online Status: Offline
Posts: 1345
Post Options Post Options   Quote davidyacht Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 12:01pm
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.

I would be trying to really rationalise the design if I was home constructing in ply.

If I were doing it, I think I would look at making a male mould in foam, covering it in packing tape and laminating a hull & deck off this.  I don't think that this would be hugely difficult.
Happily living in the past
Back to Top
iGRF View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 07 Mar 11
Location: Hythe
Online Status: Offline
Posts: 6499
Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 12:02pm
Originally posted by kneewrecker


Originally posted by iGRF

Curves how do they deal with that? Segmented strips?

clinker.


Nooooooooooooooo
Back to Top
tgruitt View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 02 Dec 04
Online Status: Offline
Posts: 2479
Post Options Post Options   Quote tgruitt Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 12:14pm
It's essentially a Vortex isn't it?
Needs to sail more...
Back to Top
rich96 View Drop Down
Really should get out more
Really should get out more


Joined: 20 Jan 05
Online Status: Offline
Posts: 596
Post Options Post Options   Quote rich96 Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 12:20pm
Is there a generic issue trying to make a boat for the puddle and the sea ?

I.e fast tacking, manouverable dinghies are not traditionally good on waves and larger stretches of water

Horses for courses ?

Back to Top
 Post Reply Post Reply Page  123 7>

Forum Jump Forum Permissions View Drop Down

Bulletin Board Software by Web Wiz Forums® version 9.665y
Copyright ©2001-2010 Web Wiz
Change your personal settings, or read our privacy policy