Profiling a timber centre board

[*J*]

I am contructing a timber centre board for my 12ft sailing dinghy and would like any advise in regards to where i might be able to access some profile designs or any general advise in regards to construction of centre boards would be greatly appreciated.

Thanks.

[Raggi_Thor]

NACA 0012 is a safe way to go.
You can search for "Profili" if you want to see a lot of different profiles.

0012 means that the thickness is 12 percent of the cord length. You can scale this to match your desired thickness and cord. 10% is quite common for keels, while 15% is often used for rudders.

Here is from
http://en.wikipedia.org/wiki/NACA_airfoil

[bistros]

Originally Posted by *J*

I am contructing a timber centre board for my 12ft sailing dinghy and would like any advise in regards to where i might be able to access some profile designs or any general advise in regards to construction of centre boards would be greatly appreciated.

Thanks.

Lots of great (and many bad) boards are home built. Each boat design will have a board design that works best for it - balancing lift, drag, depth, profile, board shape and lots of other factors. A high speed skiff-style boat will need a very different board from a yacht tender designed for high weight and low speed. If performance upwind at planing speed isn't within the design brief, good boards can be made from laminated plywood and epoxy.

Typical board cores are Western Red Cedar and foam. Foam cores can be hot wire cut like a glider wing to meet a NACA profile. WRC cores are usually shaped on a CNC table in professional operations. Molded cores are done for higher volume production boards.

If you are building a timber core, cut the timber into 1-2" strips, reverse each second strip and laminate them back together. This will prevent warping of the core.

The Swiftsolo website has a good tutorial on building WRC core boards. Phil's Foils is a good website to review as well. Locally to you, there are a lot of homebuild Australian classes with good material in their websites.

Cheers,

Bill

[The Bigfella]

I did a thread on this over on the WBF a while back

http://www.woodenboat.com/forum/show...ht=centreboard

[Manie B]

I am busy working on my centre board and rudders at the moment

Manie's Microcruiser

I got the idea from Duckworks. it works well, you still have to take care, dont rush and be carefull and accurate. Your table / workbench MUST be flat and very sturdy.

So far it looks like i will get accuracy of below 0.5 mm over 2600 mm x 400 mm
Lot of hard work but i am using my centreboard as a plug to manufacture the casing. I designed my casing to go thru the boat, bottom to top, this way the loads of the centre board and bulb keel are distributed between the hull - bulkhead AND cabin roof.
This is by no means a perfect solution but it seems like the best one for the application.
Show me a perfect boat and i will kiss your ******