Author Topic: Sensible ways to spend a rainy bank holiday.  (Read 14814 times)

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Offline Will_Lee

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Sensible ways to spend a rainy bank holiday.
« on: May 26, 2008, 10:46:56 AM »
1) Vac bag a centreboard....

ghislain_devouthon

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Re: Sensible ways to spend a rainy bank holiday.
« Reply #1 on: May 26, 2008, 11:19:56 AM »
Well done, it seems awesome.

How did you shaped the foam core ?

mathew_harris

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Re: Sensible ways to spend a rainy bank holiday.
« Reply #2 on: May 26, 2008, 01:31:17 PM »
2) Attend events trying out new t-foil ideas (don't know how much lift this aerofoil will give)

ghislain_devouthon

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Re: Sensible ways to spend a rainy bank holiday.
« Reply #3 on: May 26, 2008, 02:04:52 PM »
2) Attend events trying out new t-foil ideas (don't know how much lift this aerofoil will give)

Do you know what ?  During my last event in low low low wind were it was obvious the T-Foil was a brake, I've had time to think of a double rudder.

Actually nearly 2 rudders flued upside down. One with a T-Foil, the other without. Depending on the weather I decide between races in which way I insert it in the cassette  ;D ;D ;D. I haven't tried thought.

Offline Tim Noyce

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Re: Sensible ways to spend a rainy bank holiday.
« Reply #4 on: May 26, 2008, 06:12:53 PM »
Well we used this method as we lost the gearbox, tiller extensions and all the running gear into the bottom of Bala Lake (whoops). In 20 knots it doesn't seem to have any dramatic performance loss, even with the 3 8mm holes through the bottom which you would normally use for tying a handle! Spoiler technology is the future!

Offline ross_burkin

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Re: Sensible ways to spend a rainy bank holiday.
« Reply #5 on: May 27, 2008, 02:25:51 AM »
Well done, it seems awesome.

How did you shaped the foam core ?

A basic guide


1) Print out template.

This has the outline of the board and several contour lines. Each of these contour lines have a corresponding depth to which they need to be routed to. It's like an OS map.

You then poke lots of holes along these lines to mark the foam underneath.

2) Route out along the lines at the relevant depth.

3) Start sanding and sanding and sanding and sanding and sanding until all the grooves have disappeared and your left with a rather sexy looking bit of foam if all the curves are in the right places.

4)* (optional) Margarining. This is when you make a mixture of epoxy and micro balloons to the consistency of margarine (surprisingly enough) and you smear it in a VERY thin layer over the surface. This is to fill any open cells and stops them soaking up resin during the lay up.

5)** Lay up. Choose your bits of cloth, cut them to size, mix your epoxy and then wet out your first layer. Drape it over the board and roller it on to make sure its in place properly. Repeat. MEASURE TWICE. CUT ONCE.

6) Vac bag. Roller a layer or two of peel ply over the carbon. Then a sheet of 'bread wrap' (plastic sheet with holes in. The same stuff you get baguettes in) goes on, then breather cloth, then bag. Switch on the pump and look for holes (Will and I found countless amounts).

* We decided against this as we were using 200 foam which has very small cells and I don't think we could be bothered! The weight saving is minimal on board or rudder/T-foil but on a hull it’s a must.

** There are two ways to lay up AFAIK. There’s the way I described above and then there the way we did it this weekend. We put the board on its bracket (Will, if you have a picture post it up. If not I'll whip up a diagram in paint) and paint the board in epoxy. Drape the dry cloth over the board and wet it out in situ. Be careful to support the board, especially at the tapered end! I think the first way is easier but we ran out of space in the garage.

Considerations for next time

Use lower density foam. It took an absolute age to sand this board to shape!

Use a thicker, more robust bag.

Put breather cloth along the length of the air line that is inside the bag. We ended up with a slight crease in the leading edge.

Don’t lay up in situ. Try and wet out then drape over the board as it’s far easier. We had trouble trying to get the cloth to stick to the trailing edge (damn you gravity!) and there were a few slightly dry spots. It is hard to spot any dry bits when the cloth is vertical and in slight shade.

Make sure you know what nozzle to attach your airline to!

Get as much done before hand as possible. We faffed about a bit with locating items etc and decision making. Deiced how you’re going to do it and then just man up and get on with it.

Please correct anything if it’s wrong. If you have any advice please contribute! I’m soon to be building a new rudder/ T-foil solo so the more advice the better.


:)
2675 Fuzzy Logic  97/05 rules

Serious plannage in the works...

Offline ross_burkin

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Re: Sensible ways to spend a rainy bank holiday.
« Reply #6 on: May 27, 2008, 04:42:20 PM »
A couple more pics from the weekend.
2675 Fuzzy Logic  97/05 rules

Serious plannage in the works...

Offline phil_kirk

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Re: Sensible ways to spend a rainy bank holiday.
« Reply #7 on: May 28, 2008, 12:46:35 PM »
There was less rain and more sunshine at Bala so I think we made the right decision.  I am glad to announce that today Sarah's bruise matches the colour of the boat. yesterday it was closer to Shiny's paint colour.  She's walking around more now too.

Will, Could you send me the offsets for your  T foil?  I must get started on one as I think we have got to grips with the boat without one and we will soon be fending of Born Slippy on the race course with the speed's that she was going on weekend.

I was really impressed with Rolands extra light rudder stock and simple control system.