Critical measurement Issues?

[Warren Nethercote]

Chad, on reading your build log I saw reference to some recurring measurement issues, one evidently being width at the transom, another being the J measurement.

I too am a measurer, but for the ultimate sandbox, the Optimist. When the class introduced the IOD 95 they started with the glass boat, and while it was 'fair' in a naval architectural sense, it did not have gunwale half-breadths that represented natural bending curves for a wooden boat (whether 'traditional' or 'stitch and glue') built over only the transoms and the midships bulkhead. We soon learned that a temporary bulkhead between midships and the stern transom had to be used and left in place until the gunwales were installed if a wooden IOD 95 were to meet half-breadth tolerances at the sheerline.

Based on your experience to date, can you identify recurring measurement problems for the i550 and offer advice as to how one might best avoid them. In principle, the i550 tolerances are reasonable, albeit not generous, so passing measurement should not be a big deal. But there may be traps (like the IOD 95 half-breadth problem) that are avoidable with knowledge beforehand.

[Chad]

The current rules are based on the boat that results from building to a kit or the plans. The tolerances are really easy to meet. This wasn't always the case, as mentioned in the blog post you found- some of the rules were based on frame sizes, and the finished boats were too wide. That was corrected a few years ago now. A motto that used to float around a lot was "buy the plans, build the boat". With that approach, you won't go wrong!

I look forward to seeing pics of your progress.

[i550sailor@aol.com]

It looks like tyveks are now $175.00, which may be a bargain if you value your time. I used highlighters to mark my Miranti plywood (no waiting for paint to dry) and it left a sharper line.

Welcome to the fleet Warren,,,,, and enjoy your build. I am getting near the end of my build and will miss the time I spend on it.

[Warren Nethercote]

Thanks Chad and i550sailor.