: One option would be to scale her whole boat down. The magic number is 0.87.
: You could use an even lower number (up to 0.79( because the Guillemot was
: designed with a displacement of 240 lbs (if I remember correctly). How did
: I get those numbers? The weight change is linear but the volume change is
: cubic (L x W x H = V). So to change the boat from your weight to hers
: divide her weight by yours and raise it to the 1/3 power (take the cube
: root): 120/180^(1/3) = 0.87
: 120/240^(1/3) = 0.79
: Simply scaling it by 2/3 (120/180 = 0.667) would give a displacement of only
: 0.6667^(1/3)x240 = 71 Pounds!

: Another option would be to use the full-size forms you'll make for yours and
: use them for hers just change the distance between them (say 11"
: versus 12"). Nick's book has a section which explains it beautifully.

: Not sure about question #2... If you scale the whole boat uniformly, all the
: design ratios stay the same. I have a limited background in naval
: architecture (2 classes in college about 15 years ago) and only with play
: with with boat design on a limited basis. Others on this board would know
: better. They do it everyday.

: Hope it helped. Best of luck.
: Dan

: BTW: The first kayak I built was a Guillemot. Pretty design.

Dan,

Thanks for taking the time to reply. Exactly the info I seek. After posting my note last night, I sat down to study up on my strongback/forming process, and only then did I come across the 'modification' appendix that you spoke of. Your rational for a '7/8ths' scale makes sense. Planning to build the boats simultaneously (luckily, I have a large enough open basement), so I'm prepared to cut two sets of forms anyway. I can run a set of prints for the lofted offsets at full scale, then print another set at 7/8 scale, so really no extra work involved. Thinking I'd change the entire scale, rather than just reducing the spacing of the forms on the strongback. As you mentioned, that should resolve my second concern.

Took a look at your website. Your boats are beautiful. Do have to ask about your commenting on the Guillemot as being "...a handful, at first". Anything we should be prepared for?

Thanks again for your reply. Anyone else wanting to throw in there two cents worth, it will be appreciated.

Todd