BYYB Forums

[attachment=1648]
1. When using a batten to mark and draw a curve, make sure that it bends symmetrically! (Then double-check measurements after drawing it.)

The brown arc shows (approximately) what the curve of the cabin bulkhead top should have been. You can see that the actual middle point of the arc I cut (yellow) is to the left of center a couple of inches. This resulted in raising the port aft end of my hatch slider about 0-3/4" (the blue arc). Oh well. "Build to the work" PAR wrote some time back.


[attachment=1649]
2. When building a kick-up rudder, the angle of the transom relative to the hull bottom isn't as critical as when one is building a barn door style (such as in Paul's modification). In the plans it says, "A lot of the time [dimensional] variances will cancel each other out, but sometimes they'll gang up on us, resulting in a noticeable difference."

I think that a combination of:

• stem notch for the hull bottom not deep enough
  
• hull bottom pieces cut a little too long
  
• aft deck pieces cut a little too short
  

may have resulted in my transom setting at a tighter angle than it should have been. (Interestingly, this occurred in my scale model as well.)

So I built a structure that positions the upper gudgeon to place the rudder at the correct angle. (My rudder is already built.)

When making any curve, the most important thing you can do is "eyeball" it, from several vantage points. You'll be looking for any humps, hollow spots and generally unfair areas that need attention. Another issue with battens is, it needs to run well past the end point, so the curve doesn't flatten out near the actual ends. As you place nails or weights to spring the batten against, an area past the end of the curve also needs to be constrained or this will happen. Lastly on battens, they need to have consistent grain or they don't bend fair. If there's grain run out, twist and defects in the wood, it'll bend differently in these locations.

As any hull gets built, inconsistencies work into the job. The thickness of a pencil lead width can amplify these inconsistencies to pretty big inaccuracies from one end of the boat to the other. This is normal and you have to "build to the work" not the plans or any dimensions they might contain. On your transom, just lay a straightedge on the transom and extend this line down into the skeg. The angle isn't so important, so long as it's a straight line. This will let the pintles align properly, with a uniform gap.