Fastener Depth Too Deep?

[RIWATER]

I am in the process of refastening my concordia yawl. This boat was originally partially planked with Larch (approximately 2/3 below the waterline from the keel up. Some of the original drilled holes are countersunk up to 5/8 inches deep. I do not know how thick the planks are as I have not removed any. Can I leave these screws or should I re drill with a larger screw?

[JimConlin]

I'd ask Peter Durant at the Concordia Company. There are about 103 of these lovely boats, and Concordia would have faced this question.
(508) 999-1381
pdurant@concordiaboats.com

[ 12-04-2005, 03:15 PM: Message edited by: JimConlin ]

[Bruce Hooke]

It seems to me that it is going to be hard to judge this issue without getting some idea of how thick the planks are. Are the plank ends exposed at the transom, because if so then you should be able to tell how thick they are there.

[RIWATER]

Thanks for the help. It looks like I am going to call Concordia.

[Thad]

Those planks should be 1 inch thick and a 5/8 deep countersink is much deeper than needed. Ideally the countersink should have minimum depth leaving the maximum stock under the fastener head. Bungs work best with 3/8" countersink although 1/4" can be workable. I hate to see the countersink cut the stick in half or more. With planking 5/8" thick or less it is much better to putty over a shallow countersink. As far as I know, all the A&R built Concordias were planked with African mahogany/khaya.

[seayou77]

I agree with Thad, one inch thickness. Depth should be one third the plank thickness. Larch is good stuff and used on the earlier boats 7 and 8. Heart pine is a suitable substitute as American larch is not as tough as the european variety. Original screws were metric and easily up-sized to a #12. Good project!

[luke277]

if you are looking for some great wood screws for this project check out www.oemfasteners.net (http://www.oemfasteners.net) they can manufacture any size and lenght you might need in any material and since you might need a good number they will mostly be the cheapest place to get um plus thier made in the USA if the matters to ya
Luke