Shape of the bulb and keel cnc

[niels163]

Hi,

i’m waiting for my cnc wood, so in the mean time I would like to start with the bulb of the keel. I only have the drawings of Janusz and there is the bulb drawn with a torpedo shape without very specific dimensions. Is the shape of the bulb strictly as on the drawings or is it just the total weight of lead that is the measurement to fulfill?

I’ve read the thread about the keel measurements and the curved plate. Is there a cnc file or a cad drawing I can use to go to a construction company here in the Netherlands?

Thanks
Niels Hull 163

[captdan]

Hi,
The measurements on the plans are good to use for the bulb. Mine worked out perfectly to the desired weight. I have a CAD drawing of the side profile of the bulb. Facebook message me and I will send it to you. @littlebeasailingadventures
Email Jane and she will send you the CAD file for the Keel.
Cheers,
Dan

[martellmarine]

Jan 12, 2022 2:44:04 GMT captdan said:

Email Jane and she will send you the CAD file for the Keel.
Cheers,
Dan

I got the keel and bulb CAD file as part of the purchase of the compulsory stainless steel pack. In other words, you purchase the stainless pack and get the keel CAD details.

If building the bulb by hand, you have to be as accurate to the plan as possible. You are not allowed to reshape the bulb to something different from the plan with equal weight. The shape can be checked at a latter date by measurers as part of class registration.

Cheers
Greg

[Gary.S]

A pattern for the bulb is very easy to make if you follow the measurements on the plan . I added about 1.5% to the measurements for shrinkage once the lead is cast. There are some pics on my blog if you want to take a look.
Hull # 111. It's much easier to take some lead off if it a bit heavy than to add lead if its a bit light.

[brucel]

If you search the builders facebook group this is some good discussions on keel bulb shape and what profile it is. The CNC file is not required to cut your steel as a most cutting places would be happy to have a 2D pencil drawing as good as ours to develop a cut file from.

[niels163]

Thanks all for your reply.
I've shaped the bulb following the measurements on the plan, including the 1,5%.
Thanks

[hull113]

We added about 1.5% shrink to the pattern and the lead didn't shrink at all. I don't know why. I don't know the actual source of our recycled lead, but I suspect that it has some antimony in it which negates shrinkage.

In any case, it's not too hard to remove the extra material. A cheap electric planer works pretty well. Ours is pretty beat up and it makes some bad noises, but it works okay.

Hull 113