Rascal the sequel

[gert]

If a person thought a boat design was great but just a mite small what would be the ramifications of taking all the plans including full size frame paterns and having them enlarged (at a profesional reprografixs firm) by 10%. This would make a 14'-10" x 5'-4" boat 16'-4" x 5'-10"

[ 11-20-2002, 10:16 AM: Message edited by: gert ]

[Steve Lansdowne]

Do it and find out! I'm no expert, but I've read a lot. Sometimes boats are lengthened a foot or two by spacing the frames, say, 14" instead of 12", with no adverse effect. From what I understand widening the beam is not a good idea, as the resulting boat's displacement becomes much different and likely won't handle as the original boat did. In the case of a sailing vessel, the changes can complicate the appropriate balance of the rig, etc. I'm actually way out of my league here, but you'd be safest either hiring a nautical architect to help with this or, better yet, get plans for a larger boat. There are certainly plenty out there to choose from. G'luck!

[gert]

actualy there arn't lots to choose from, or I'm not looking in the right place. I have only seen about 3 that I have given serious consideration to.

[Figment]

I've had my drawings screwed up by professional reprographics houses too many times to trust the consistency of their enlargement processes. Take two drawings that you know to be identical, and have them both enlarged, then lay the enlargements over each other. You'll be shocked.

the discrepancies created by the 10% enlargement might fall within construction tolerances, but if I were in your shoes, I'd do the math and re-loft. Or, as others have mentioned, find another design that's the size you want.

[chesterm]

What Steve said. Lenthening a boat by 10% or so usually is ok. Maybe add 2" between the frames from the transom to probably the third station from the front, add 1" to the second station from the front and none to the forward most station. then loft everything and go. widening a boat is probably not wise wihtout the belssing of the designer. good luck, mitchell in CT

[PugetSound]

Gert,
Increasing the scantlines of a design by 10% is one thing (generally it works out OK) but having the patterns increased by photo-reproduction is quite another. I think that it is a very very very bad idea to increase patterns or measurable drawings in this way because the process does not guarantee faithfull reproduction of all angles and lengths. Generally, the angles come out a bit off (try it on a photocopier). Some of this is deliberate - to discourage counterfitting.