Twisted hull?

[Anastasia]

As I move through my survey, I'm beginning to think the hull of my 17 foot lapstrake sailboat is twisted.

Some issues that make me think the hull may be twisted include lap seams opening on the port aft and star fore; a rib pulling up from the floor on the star fore. Spacers added to the star aft benches. Also there seems to be quite a bit of checking at the butt blocks.

I have not found much frame damage, except for where the ribs join on top of the floor. There, I find some cracking that seems to correlate with the fastening of floor boards.

Since buying this boat, I have learned a foredeck was added over the breasthook. I'm thinking maybe this started the twisting. I'm interested in taking the foredeck off anyway to return it to the original design. Could it be a practice to add a foredeck if there is breast hook problems? Should I have other concerns about removing the foredeck?

Does anyone have any wisdom to share on this issue; such as how to go about untwisting the boat.

[Jack Heinlen]

If you're wondering if it's wracked, ie it isn't obvious, it probably isn't twisted much. Someone will chime in with simple way to measure it.

If it is wracked, and the deck was laid with it wracked, the only way to fix it would be to pull the deck, but contemplate and look before you do anything drastic. Even slight asymetry will be available to your eye if you spend some time.

[Bob Smalser]

As you have already removed thwarts and benches. which are structural, not cosmetic members, I wonder how to currently have the boat supported?

If on sawhorses, then building those sawhorses up into a cradle for better support is a good idea. Get sawhorses dead level, then simply add beveled blocking to level the boat and support the bilge. Make sure the boat is setting on frames at each horse, not planking alone. You can also add a full-length 2X6 with beveled blocking to support the keel, if the boat is hogging or sagging along that line.

Block the boat up thoroughly, and the twist may disappear by itself.

Otherwise, horn and plumb the boat to see how much twist is in. Tack and stretch a line or dead-straight batten from the center of the stem to center of transom. From the stem tack, run a steel tape and measure each corner of the transom and each frame head center, record and compare. Discrepancies between one frame and it's mate on the opposite side of the boat help tell you where the twist is.

Also measure halfbreadths from your centerline if any of those look off. And once the sawhorses/blocking are level, a mason's level laid on a straight batten across the gunwales will also show where the twist is.

Don't dismantle anything else to you are sure the boat is supported as true as it's gonna get, then remove your foredeck and finish the boat. It should sag into your supports by itself. Properly-sized and fastened foredeck, thwarts and knees should keep her that way.

If it's worse than that, then come back and ask about jacks, come-alongs and other forms of rougher persuasion before reinstalling thwarts and decks.

[ 10-18-2003, 08:39 PM: Message edited by: Bob Smalser ]

[Anastasia]

Thanks, Jack and Bob.

Right now the boat is still on its trailer. Last week we put a big hole with cover in the side of our work shop so that we could move her in there. The fore thwart I never took out and I was planning on temporarly installing the aft thwart before I trucked her to the fellow who is going to go over my assessment of her. After that I was going to put her in our shop. I'll check the horses for level and other supports.I guess I will take out both thwarts while I work on her to allow her to untwist herself, if she in fact measures out as twisted.

I'm thinking the white rubber substance (caulk?) could have been put in the lap seams because of the possible twisting of the boat. And that untwisting her might make the lap seam more flush. ( Wishful thinking?) If that is the case, it seems that cleaning out those seams with a sharpened tang of a file would be a priority. Are there any tricks around to cleaning out caulked seams?

It also seems that a foredeck would give more structural stability to a boat's bow; however, in communicating with Dick Wagner who originally imported these boats (Rana's from Noway) I learned that these boats originally only had a breasthook, and that by putting a foredeck in the boat the center of effort for the sails was changed because the foreward stay was moved up to the stemhead from farther on the stem. For the reasons of the original design and sail performance I would like to go back to the breasthook.

Thanks again for your help.