Chine Upsweep

[maa. melee]

Bolger's Skiff 18 calls for a 1" X 1.75" chine. As you may already know, the skiff has plumb sides so bending the chine to the camber of the sides won't give me natural upsweep. How do I get the chine to sweep upwards at the bow? Do I steam bend the chine along the wide plane (the hardest way to steam bend) or saw it out of bigger stock?
Natural Upsweep (http://img.photobucket.com/albums/v197/maa_melee/rocker.jpg)

[ 03-11-2005, 12:51 PM: Message edited by: maa. melee ]

[John Bell]

I think you're thinking too hard. smile.gif You ought to be able to bend it in dry without too much trouble. That's certainly what Bolger intended. I'll bet if you called Dynamite Payson and asked him, he'd tell you the exact same thing, except he'd use fewer words. :D

(Yep, I've talked to Dynamite, too! ;) )

[Bruce Hooke]

I am not familiar with the design so I may be off the mark here, but usually the chine log is bent into place around some sort of building form that holds it in place until the planking is attached to it, at which point it is firmly anchored in place! The form itself gives you the smooth curve you need. On some boats the bend required is too tight and fancy things like steambending or bending in two parts and gluing have to be resorted to, but it seems like it would be unusual for a Bolger design to require such shenanigans.

[Dennis M]

It is an "external chine log", yes? When you have the sides the boat planked up (and before the bottom is put on), you should be able to bend that log around the outside of the hull with little difficulty. It will follow the curve of the hull without any problem. Glue and screw it on (from the inside) every 4-6".

The topside of external chine on my Featherwind did not mate with the plank leaving a gap that needed to be filled and faired with epoxy goo. Watch for this and either use an extra strategically placed screw or two or clamp it real good. Should be fine.

[John Bell]

The boat is Bolger's 18' Clam Skiff, alternately called the 18' Work Skiff on Dynamite Payson's http://www.instantboats.com web site. The chine logs are inside on this boat.

You could set the frames/bulkheads up on a strongback to build this boat, but it's not necessary, IMO. If it were me, this is how I'd do it:

1) make all the bulkheads, the transom, and the stem. Pre-notch the bulkheads for the the chine logs.

2) cut out and butt the topsides.

(Prepare to assemble the boat right side up.)

4) Start by fastening the topsides to the center bulkhead, first the starboard, then port.

5) Alternate working forward and aft screwing and gluing the bulkheads to the topsides until you finish with the transom and stem.

6) Turn the boat over.

7) Spring in the chine logs, screwing and gluing as you go.

8) Check to see that the boat is square and level, then nail the on bottom.

9) Etc., Etc.

Does that make sense?

[maa. melee]

Makes alot of sense, John, thanks. I was planning to do the same but was worried I'd split a chine if I forced it to conform to the sides. I think the key here is to have the sides setup sturdy enough so the chine won't deform the hull. Granted it's not a huge bend. A few screws and I think the chines will stop being so wayward. Thanks again all of you.

[John Bell]

The chine won't deform the hull at all. In fact, it will smooth out the curve of the topsides between the various framing members. You ain't gonna affect the upward sweep of the 1/2" thick by 2' tall topsides with the stress imparted on them by that puny little splinter of a chine log, if that's what you were worried about. No matter what his various detractors say, Bolger does know something the construction of boats like this. Trust in Phil, I always (well, usually;)) say.