Rub rail question

[tapsnap]

I'm building a glued lapstrake Dory and I'm about to attach the rub rail.
The plans show that it is epoxied and nailed with anchor fast nails. I'm thinking that it would probably need to be replaced at some point. Should I screw it on and use bedding compound instead or is the glueing and nailing required to stiffen the sheer?

[Mrleft8]

Rivets and bedding compound is how I'd do it.

[Thorne]

I hates those nails, I does, and epoxy would sure make replacing the rail difficult.

Rivets and bedding compound sounds good, as does one of the more flexible adhesives like 5200 or Vulkem116 and screws. You can usually cut the adhesive free from the wood with a knife or hot wire after removing the screws.

[rbgarr]

If you use bedding compound it's worthwhile to back out the faying surface so that it's concave and forestalls water from getting underneath.

[TerryLL]

Which dory? Not that it makes any difference because my advice would be the same. Bedding compound with screws, bungs set in varnish so they can be easily removed. If you fear for the stiffness of the sheer, then add an inwhale, which can be epoxied in permanently. But if the sheer plank is already on, and the frames extend to the sheer, then adding an inwhale as an afterthought is darn difficult.

[Wooden Boat Fittings]

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By all means use bedding compound if you want (although I myself wouldn't bother, provided everything is painted or varnished all over before assembly.) But I certainly wouldn't fasten rubbing strakes with anything but unplugged screws. By their nature such strakes are sacrificial, and you want to be able to replace them if necessary without trouble. Epoxy and ringnails would make it almost impossible to do so without damage to both strake and hull.

http://www.woodenboatfittings.com.au/boats/aileenlouisa/al-bow-s.jpg

[Peerie Maa]

Personally I would plug the screws, It looks nicer, is easier to sand any dings before re varnishing, and is nicer to the neighbours.:o

[MiddleAgesMan]

Why not screw from the inside and leave the heads exposed?

[Wooden Boat Fittings]

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Those screws in the picture are all countersunk -- they're not going to damage anything. Plugs are for screws that are unlikely to be removed. Rubbing-strake screws don't fall into that category in my opinion. For revarnishing you simply take the strake right off and do it properly (including the back if you want to.)

Mike

[JimD]

Any chance the designer considers the rails to double as structural as a sort of outer shear clamp? That would explain the epoxy.

[ishmael]

As you say, a rub rail ought to be potentially sacrificial. Epoxying it, unless that is somehow integral to the structure, is going to make replacing it unnecessarily difficult if you tear it up. Is there an inwhale on this boat? I don't imagine bedding it and screw or rivet fastening would change the stiffness/strength characteristics much. Can you contact the designer and ask?

As mentioned above, if bedded and mechanically fastened back the underside, the side against the hull. It's a simple matter of a slanted jig and running it over a table saw. Too involved to try to describe, but most good books will show you how. This insures good contact with the hull planking both top and bottom.

In a dory, with a lot of flair amidships, it can be difficult, but make the rail if not rounded a trapezoid in cross section, with a slanted underside which will keep it from hanging up on posts and such.

One final bit of advice, something that amateur builders of small boats rarely do but which makes a world of difference in the final appearance of the boat, is lighten the ends. By which I mean cut a light taper, both up and down and in and out, in the last few feet of the rail at both end. It's not tough, use your eye and a jack plane, and keep the transition smooth. Nothing radical, say in a rail that's an inch and a quarter you want the very end to be a strong inch, starting the taper maybe three of four feet back. In a boat with double rails as pictured above it might not be appropriate. But with a single rail it really is much more pleasing to the eye than the clunk of a continuous line.

Good luck.

[tapsnap]

Any chance the designer considers the rails to double as structural as a sort of outer shear clamp? That would explain the epoxy.
This was my concern and part of the reason for asking the question. Thanks everyone for your replies. I think on second thoughts I will just go with what the designer intended. If I have to replace it, pulling out the nails will chew up the rail but it will be garbage anyway. Then I can saw off the rail close to the strake and clean it up with a block plane.

[Wooden Boat Fittings]

... cut a light taper, both up and down and in and out, in the last few feet of the rail at both end. It's not tough, use your eye and a jack plane, and keep the transition smooth. Nothing radical, say in a rail that's an inch and a quarter you want the very end to be a strong inch, starting the taper maybe three of four feet back. In a boat with double rails as pictured above it might not be appropriate. But with a single rail it really is much more pleasing to the eye than the clunk of a continuous line.

I quite agree with you Jack, the rubbing strake certainly looks nicer if it's tapered at the ends.

In the case of the double strakes on Aileen Louisa, although the strakes themselves aren't tapered, they follow each edge of the sheerstrake (which of course is widest at the centre) and this gives much the same effect.

http://www.woodenboatfittings.com.au/boats/aileenlouisa/al-trailer3.jpg

[Candyfloss]

Here in Kiwiland we avoid inwales by preference; they make it difficult to get the sand out of your dinghy, so we glue the gunnel on for strength & fit a rubrail outside of that. Rope for a traditional look, but more likely a propitiatory product, rubber with a white plastic pipe insert. Very smart for about the first season, but easy to replace.
P.S. Tell me about your build please. I have a thread called "My new build" by Candyfloss. My name is Graeme.

[ishmael]

Hi,

Those rails on Aileen Louisa look right to my eye. They are light, so a taper would be redundant.

When I look through the new builds of small boats in WB magazine I'm often struck by what a difference a couple of strokes spent tapering the rub rail would make in the aesthetics of this small boat. It's not a big deal, but I often remark to myself, "That boat would look a lot better if you'd tapered the rails a bit." Without the taper the rails look clunky. Little details like that make a huge difference. Not functionally, but aesthetically.

[JimD]

... I can saw off the rail close to the strake and clean it up with a block plane.

You might want to use a belt sander. The epoxy will be murder on your plane.