Dinghy Gunwhale/Rub Rail Replacement

[MattG]

Hello All...

I am rebuilding an old Alberg 8' fiberglass sailing/rowing dinghy. The old teak gunwhale/rub rail was split/delaminating/generally banged up. It was made up of 7 layers of approximately 3/16" teak strips laminated together, three layers outside the fiberglass shell, two inside, and one straddling the shell. The gunwhale is about 1-1/4" high. The bow of the dinghy has a fair amount of curvature, I haven't measured it but would estimate the radius to be about 1 to 1.5 ft.

I am trying to decide how to best replace it. In my mind I see two options, but not sure which is best. One is to replace the gunwhale with what was there, by laminating teak strips in place using the hull as the mold. But I am not sure if teak can bend around the bow without being steam bent. This method might also be more expensive because of the waste in the process of ripping the strips, and I am not sure if I can get strips ripped this thin. I could try it on my own, but my small table saw is probably not up to task.

My second thought was to steam bend 1/2" strips for inside and outside the hull. There would be less wood waste, but it would seem harder to get the bent curve right (with springback...).

Any thoughts are appreciated...
Matt

[MattG]

To add to my question...should I even be using teak for this application? I believe it was teak...but just my layman's guess. I am certainly not stuck on any wood type, just want something that is strong and easy to build/install.

[Ian McColgin]

The bend could be a pain if you must use new wood. I made fir gunnels for a dink with a similar bow, replacing the nasty aluminum gunnels, and the 1/4" strips I used got around dry without breaking but it was a close pain.

I didn't bother with a cap piece for that boat but were I trying to hide the top edge of the glass, I'd not go through the pain of a flat cap. Instead, I'd have a small almost square section to sit right on top of the glass and be contained inside and out by having the other strips come proud of the glass top by 1/4" or so.

G'luck

[shadow99]

I used Ash for my rubrails, takes all sorts of bends & twists with no problems, yet hard enough to provide some bump resistance.

Rick

[Bruce Hooke]

A good way to get a sense for where you stand at relatively low cost would be to rip three 12-18" long strips of the right width and thickness and try to bend them around the tightest curve.

It is unlikely that they steam bent the teak -- from all I've heard teak does not steam bend well; the steam just does not have that much affect on it. Also, in my experience steam bending and laminating are best NOT combined. I've had trouble with the steaming process contaminating the surface of the wood and interfering with the glue bond. So, if you are going to laminate, then rip the strips thin enough so that they don't need steam to bend.

If you have a good steam setup then it might be easier (and more fun) to just steam bend full thickness pieces of something that does steam well. You could pre-cut a lip on the outside piece to cover the edge of the fiberglass. Make sure you put this lip on the outside piece so that it is on the compression side of the bend.

The advantage of teak is that it can be left unfinished pretty much indefinitely. However, if you don't mind keeping the gunwale finished there are plenty of other suitable woods out there. Honduras Mahogany steam bends well and can be left unfinished without getting damaged that much. White Oak steam bends wonderfully and is rot resistant (as are teak and mahongany) but it turns black, especially around fasteners, if it stays exposed to the weather. Ash steam bends well but it has little rot resistance and also needs to be kept finished...

[Scott Rosen]

I thought the whole idea of laminating thin strips is so you don't have to use steam. If you laminate with epoxy, make sure you apply a UV resistant finish, or the sun could attack the glue joints.

[Bruce Hooke]

I wouldn't be too worried about the sun getting at the glue joint; after all, it's only a hairline edge that's exposed. What I would be a bit worried about is epoxy's ability to withstand the stresses of unfinished wood trying to move as it takes up and releases moisture. That said, I'd guess that it would do fine in a gunwale as long as the boat is not left turned upside down in a puddle for days on end or otherwise mistreated.

[Carlsboats]

Most of the small boats I have seen with laminated, unpainted rails have been coming apart -- especially with teak glued with epoxy.
Two ways out of this: (1) Don't use teak, but go to ash or mahogany for a bright finish, or to oak if you are going to paint; (2) Laminate on both sides of the glass, using resorcinal resin glue. If you laminate on the job, instead of over a form, and if the laminates are fairly thin, there won't be enough spring-back to bother you. As for fastenings, I favor copper rivets --easy to use, should last forever.

[Mrleft8]

I've said it before, and I'll say it again.... Think bandsaw blades.
You stack a bunch of blades (old ones), bend them around your gunwhales, and weld them together. Bolt or screw them to the hull, and you're all set. Nobody will ever ram into you once they've seen your armour. People will actually go to great pains to get out of your way during regattas.

[MattG]

Thanks for all the responses, and I think I have learned a couple of things - 1. Best not to steam bend teak, 2. Don't steam bend and laminate same wood.

But I guess I still haven't figured out which method to use. I figured I would wait to decide on the paint vs. bright finish until I completed the installation...then could judge how well it would look with a bright finish.

I think I will try the suggestion of ripping down some scrap wood and seeing how well it will take the radius. Now off to sand the fiberglass...

Thanks for the responses, keep them coming...