Eric

First, nice yak. I'll add some comments to each of your points.

: I built the prototype BLUFIN this spring and am generally happy with it and
: its performance. It is a low profile multichine hull. It is intended as a
: performance touring boat. it is 18 feet by 21 inches.

18 feet by 21 inches is in my opinion, nearly ideal measurements for most people. Longer and it's ungainly in tight areas and more so, in the launcjhing and landing phases. Launching is usually early and the coffee hasn't kicked in. Landings are after 20-30 miles and the transition to standing and carrying a yak, or dealing with a loaded yak difficult at best.

: Issues I found this summer include: 1. it could track a little better to
: reduce weathercocking effect. I prefer not to have a retractable skeg or
: rudder.

Here's a suggestion: design a mount using embedded stainless steel T-nuts (I use # 10, 24 pitch myself) to screw on the skeg/replaceable abrasion strip. This also serves to fine tune what the skeg strip needs to be, too.

: 2. low profile is good in wind as is but bow punches through waves.

All my yaks were designed with low bows because they do punch through waves, particularly that critical curving lip of a breaking wave at lauches though surf on beaches. I've found that a bigger volume, higher curved bow has too much lifting forces and could cause a roll while launching though breaking waves. The downside is the ride tends to be wet but...the ride seems to be a bit more stable.

: 3. Rear deck is 9-1/2" high at combing may be a little high but it rolls
: well as is.

My first and second yaks were about the same height and rolling isn't hard.

: My current plan is to modify the tracking by adding some skeggyness to the
: stern but leave the rest as is as I am happy with it generally. I do not
: mind a bit of punching through waves and the deck seems OK to me (I'm
: 6'2") I have modified the origional plan in several ways but keep
: returning to the origional.

I'd keep it as it is if I were you. Check out item 1 above on the skeg idea.

Eric, she a real beauty, very nice lines.