What distance?

[Danielsan]

Hi there,

Is there any rule of thumb for placing (distance) the transverse sections for building up a wooden plug?

I saw building a 35 footer with the transverse sections at 70cm could I use the same distance for my 24ft boat or should it be more or less?

Any idea?

THX

Daniel

[Eric Sponberg]

Daniel,

The spacing of stations is arbitrary. Usually, the designer of the boat will specify the station spacing. Also, there is usually a mold frame at every bulkhead, the bulkhead forming the frame itself. Also, if there are intermediate frames between bulkheads, there is a form for these also--the frame is assembled over the form, and the hull is planked over the frame. A lot depends on the lines you have available--if you use the station lines from the lines plan, then you do not have to loft intermediate station lines, which can be tedious.

So to answer your question, who knows what the proper station spacing should be. For small dinghies, I have used a spacing as small as 12" (305 mm) and for larger vessels up to 85' I have used 32" (813 mm). 16" or 18" (406 to 457 mm) is about the minimum, because you as a person have to physically get between the frames to work, unless you can reach more than halfway across the boat, then smaller might do.

Eric

[jehardiman]

Depends on what you are making the plug out of, male or female, and the construction method of the finished hull. For most materials, the spacing of the forms (stations) should be ~10-20 times the thickness of material used to make the skin of the mold (hull) in order to get a fair surface to laydown the hull structure and a fair hull structure. Additionally, you have to consider the load it will see during construction and design for that.

For example, you construct a male plug for a cold molded hull. The mold is made up of 1"x1" stringers and the monocouqe hull is three layers of 1/8" WRC. The forms(stations) that support the stringers should be spaced on ~20" centers (20*1") and the stringers themselves on about 3" centers (.25"*20+.5*1").

Or a female 1/2" steel mold for sprayed on gelcoat/chopped glass/mat/chopped glass hull would have structural supports (stations, frames) every 10-12" while forming the mold to prevent warping and the mold requires a solid surface as the hull material has an effective thickness of 0". Additionaly, the mold would have to be strong enough to support rolling out of any mat reinforcement so some support structure will be needed for the mold to hold it's shape.

[Danielsan]

Thx,

I will put the stations aprx 45-50cm that would just be enough to get in between as Eric Spoonberg said. It will do fine (I hope) for my 7.50m hull.


Greetings,

Daniel Peeters