View Full Version : Wooden hull caulking below waterline

06-19-2003, 06:41 AM
I have just purchased (almost given) a 19 ft. traditional inshore fishing boat built in Newfoundland called a "Rodney" (this boat was actually used on the film "Shipping News" with Kevin Spacey)
The top sides are rustic but sound and with a little TLC will be in original condition including the hand jigging marks, however the planking (3/4" spruce??)has opened up and some of the original caulking is gone. I am in a dilemma whether to re do with traditional material or use 3M 5200 or equal??? :confused:
Other than the concern the caulking will be almost permanent is there any other drawbacks???

06-19-2003, 10:48 AM
I think that 3M 5200 is an excellent product, but unfortunately, so do worms and gribbles. They seem to love to eat the stuff. I've seen a few boats where it appeared that they deliberately attacked areas where 5200, Sika, or Boatlife caulk had been used. I'm not too sure what the solution to this is. I have some of that stuff on my boat as well, but I use vinyl AF paint on the bottom, which does not slough, so the caulk doesn't get exposed unless the paint cracks for some reason.

As far as the "oakum, cotton, then paint...", I was always under the impression that the oakum is something that you would use instead of cotton. I may be missing something here, but in any case, I would think you would have to put something over the oakum or the cotton before the paint goes on.

I think 5200 is the best of that crop of products. I just wish they would make a version that is less appetizing to bugs. I would love to hear of a better alternative.

06-19-2003, 12:34 PM
Dave, Now you've got me a bit confused. I always thought (on large planks & seams)that you started out with cotton & ended with oakum on top? :confused:

06-19-2003, 01:28 PM
Thank you Dave! It must have been one of those "brain things" makin me think the other way around. ;)

06-20-2003, 02:06 AM
Hi, JRB: On a small boat like that probably cotton--red lead--oil based seam compound will work fine. Forget the 5200 and the other tube goops misnamed "caulks"--that's the kindest thing I can say about them as substitutes for cotton and seam compound.

Dave F.: When we put our 100' schooner together, with 2 3/4" planks, the caulkers from Lunenburg put cotton first, then oakum. The cotton was socked in to the narrow part of the seam, and the oakum served as a bulk filler. The cotton went in with regular caulking irons, and the oakum went in with a hawsing iron. Then the compound, which was some kind of pitch mix that came in 5-gallon buckets. I guess the builder thought oil based seam compound would be too expensive. The team from Lunenburg called themselves "cockers" (no "r").

06-20-2003, 04:45 AM
Thanks for all your help, I'm going to keep with the traditional ways and use seam compound (making sure there is some caulking still in the seams (cotton or oakum?)
Wisk me luck (on the squid jiging grounds)
Regards.....John smile.gif

06-20-2003, 01:14 PM
Nobody talks about roofing tar to finish off the seam. Black bottom paint to cover. Any objections?

P.S.: I am looking for a boat like that to fix up. Sounds like a real nice project.

[ 06-20-2003, 02:18 PM: Message edited by: Walcheren ]