Dan,
I'm not building a boat (yet) but I have been remodeling a 90+ year old house for the last 8 years. Motivation is sometimes very difficult. It's hard to keep going when the end is not in sight. Here are some of my sanity saving sugestions:

1) Make a list of all the steps you need to complete, including the steps you've already done. keep this posted and check things off as you go, it always gives me a boost when I look back at the enormous amount of work thats finished.

2) Slip in some fun projects with short completion times (one or two days) These can be boat related or completely different. I bought an old beater fiberglass C-1 that I rebuilt and play with. Build something for/with your family (My daughter and I did one of Spideys cpvc flutes)

3) Plan ahead for a big block of time when you can really move forward.

4) If paddling is the goal use another boat to get out on the water.

5) If it gets too frustrating quit...... until you can decide your willing to put up with the iritation. Pushing ahead in the wrong frame of mind only leads to more mistakes or worse.

6) Re-read the insrtuctions and get a clear picture in mind before you proceed.

Hope this helps,
Brad