View Full Version : What's the rub on rub rails?

11-12-2003, 07:52 PM
This is probably covered already but I am looking for advice on a wood species to use for rub rails. Our local lumber yard has recommended either Ash or Mahogany. What are the pros/cons of each?

The boat is a small day sailor around 20. The rub rails will run along the shear line and then also trim the cockpit. I am thinking of a fairly thin rub-rail (1 high by .375 thick) which will be screwed and epoxied to the side of the hull along sheer. The top of the sheer would be capped by a piece of the same dimensions).

The boat has a fairly aggressive sheer so the rub rail will need to bend and the one laying on the deck will need to conform to the sheer along the thick dimension. Thus, the ability top bend (ideally without steaming) would be nice.

The deck is teak if that matters. The boat is likely to be trailered and not see extensive weather exposure but I suspect everyone says that at first huh? If it were your choice, would you go with Ash, Mahogany or some other species. Potential considerations that I have no idea on are:

Ease of bending.
Resistance to rot
Ability to hold a scarf joint
Ability to hold a countersunk screw hole

Thanks in advance for your help.


Jim H
11-12-2003, 08:01 PM
I agree with Donn. You'll need to use something other than epoxy for white oak because the tannins in the wood cause adhesion problems.

Bob Smalser
11-12-2003, 08:04 PM
It'd help to know where you are....I'm cutting a massive DF next week and a friend north of Philly a massive W. Oak. Both suitable. For what you need for just rubrails...I'd give you a couple sticks.

L.W. Baxter
11-12-2003, 08:20 PM
Are rubrails normally glued to the boat? They're supposed to be sacrificial, right? Also, on a twenty footer I would think they'd be a little thicker than... .375", as you put it. :D

Unless they're just ornamental, which they may be.

Whoops! 'scuse the redundancy!

[ 11-12-2003, 09:24 PM: Message edited by: L.W. Baxter ]

11-12-2003, 09:01 PM
Personaly I wouldn't use oak for your guard,....DF would be good, or a nice piece of iron bark looks good when all finished out. Apitong also makes a good guard, but since you have a teak deck, why not stick with teak for your toe rail as well as your guard. On the guard you could apply a piece of half oval, either bronze or stanless as a wear strip. And yes I agree guards should always be put on with the ability to be able to remove if need be.


Leon m
11-12-2003, 09:27 PM
I've used white Oak on two of my boats,and I
am very pleased with the performance.

Jack Heinlen
11-12-2003, 10:08 PM
Honduran Mahogany is hard enough for small boat rub rails.

Typically, on a small boat like this the rails don't do much hard service. They cover the deck to hull joint, protect the sheer from normal wear and tear, and act as a safety net for when the boat gets away from you ocassionally.

Of all those mentioned, oak is the most abrasion resistant. Most mahogany is at least as hard as most Doug Fir, with the proviso that stock varies a great deal.

And, as noted, don't glue them on.

Bob's offer of some Doug Fir from a big tree sounds pretty hard to beat, unless you want the jazz of varnished mahogany.

What are your plans for the rest of that lumber, Bob?

11-12-2003, 11:55 PM
Thanks all for the advice.


I live in Wisconsin (A northern suburb of Chicago). That's a very kind offer. I'm the kind of guy who's only vaguely aware that my lumber actually comes from trees. Wouldn't it have to be dried? As I only need a relatively small amount, I suspect it would just as difficult to ship it here. Thanks anyway!


Bob Smalser
11-13-2003, 12:08 AM
Green wood in the small scantling size...say 2"X 2"...for rubrails generally bends without steaming (toss it in the pond for a week stuffed under the dock floats and it'll really bend) and in a stable species doesn't shrink enuf to fret about.

You're in hardwood country...oughta be some green oak about...check with your local tree service guys...some of them have portable mills these days. And rubrails wear out...rot resistance for them in a cold climate like where I live isn't such a high priority...I'd use ash if I got it free...it's nice and hard.

The only down side is that it stays fuzzy till it dries. For a bright finish, I'd sand and varnish it like the rest and live with the fuzz till the following year when I sanded and recoated it again. With paint it don't much matter...just sand after the paint dries and add one more coat to fill and smooth.

What are your plans for the rest of that lumber, Bob? The gent who owns the tree is getting some 2X6 and 6X6 dock wood from near the pith....will cut the rest into clear 5/4X9"X12' quartersawn stock for door jambs and boat planking...with some 2X2" and 4X4" thrown in from near the pith for framing stock. Sun-grown tree near the shore, tho...may be 200+ years old but we'll have to see what the ring density is...gotta wait for my friend to wedge that big honker down, first...it's right next to the owner's house and we're gonna cable it for insurance.

[ 11-13-2003, 12:31 AM: Message edited by: Bob Smalser ]

Jack Heinlen
11-13-2003, 12:40 AM
It sounds like a wonderful tree Bob.


I think, from what you've said, that I would get some ash. It's hard, it's not terribly resistant to rot but that's not a huge issue in this place, it's local, which is always a good idea, and it should be a quarter the cost of mahogany.

And 3/8 inch thickness sounds light to me too(put away your micrometer and get out your Stanley leverlock ;) ), and there are a few tricks with rails, and... smile.gif

Keep asking.

11-13-2003, 12:59 AM
On my 18 foot skiff Tracy O'Brien recommended Walnut, which came out nice and is quite tough. I am planning on attaching a stainless strip 1/2" wide along its length. The Walnut is glued to the sheer and was scarffed for length.


Leon m
11-13-2003, 01:04 AM
Originally posted by davef:

I live in Wisconsin I know couple of mills where you can get
some green oak if your in the madison area .

Bob Smalser
11-13-2003, 01:17 AM
On my 18 foot skiff Tracy O'Brien recommended Walnut Dunno why midwesterners where it's common don't use more walnut in boats...I'd jump at it if I could get it. The plantation walnut isn't as hard as the old stuff, but some Goo Brother's miracle glop could fix that.

Wooden Boat Fittings
11-13-2003, 03:07 AM
Speaking for myself, I'd be wanting to use something a good deal harder than Douglas fir for a rubbing strake.

Douglas fir has a pretty good strength-to-weight ratio, which is why it's so often used for spars. But in a rubbing strake neither strength nor weight are the major issues, hardness is.

It sounds like a few local hardwoods have been suggested, and I'd rather see you use one of those if you can. (Sorry I can't advise further, but I have essentially no experience with American hardwoods.)

Definitely screw, don't glue.

And finally, have you considered using a second rubbing strake at the lower edge of the sheerstrake? One of these usually comes in for quite a few knocks too, which shows that it's worthwhile having.



11-13-2003, 12:16 PM
Nice looking.

Interesting comparison between old (above) and new (below)


[ 11-13-2003, 12:40 PM: Message edited by: Venchka ]

Keith Wilson
11-13-2003, 12:24 PM
Sassafras may be great stuff but it doesn't grow up here where it gets cold. Native range of Sassafras albidum:


[ 11-13-2003, 12:26 PM: Message edited by: Keith Wilson ]

11-13-2003, 12:34 PM
Ash, mahogany, oak, what ever. Use what looks good on your boat, to you. All the rest is opinion within the range of boards we are considering here.

11-13-2003, 12:48 PM
Originally posted by Keith Wilson:
Sassafras may be great stuff but it doesn't grow up here where it gets cold.Well shut my mouff.

The folks along the Michigan side of Lake Michigan will be pleased to know that it doesn't get cold there.

In lumber terms, it's local enough.

[ 11-13-2003, 01:43 PM: Message edited by: Venchka ]

Gresham CA
11-13-2003, 01:59 PM
I agree with Norm. You aren't planning on pulling crab pots or commercial shrimping I don't believe. Ash bends pretty easily at those dimensions, I put some on an old Thistle. If you want to use it, use it.

[ 11-13-2003, 02:03 PM: Message edited by: Gresham CA ]

Bruce Hooke
11-13-2003, 03:18 PM
I'm assuming your going to varnish or oil these pieces. If so, I would focus on looks first, because I think just about any wood, short of soft pine, will get the job done. The only conditions under which I've seen rubrails really take a beating is if the boat is left tied up at a dock where it spends day after day rubbing against other boats (or if the boat is a workboat and constantly has stuff being pulled over the rails). Otherwise, IMOOP if you are reasonably careful when doing things like coming alongside docks and other boats, the rubrails should not see enough abrasion for the hardness of the wood to matter.

To address your specific questions, here is my take on Ash vs. Mahogany:

Ease of bending - Ash is probably better in this area
Strength - Ash is a bit better in this area but not enough to really matter
Toughness - Mahogany is a bit softer than ash but not enough to matter in my opinion
Resistance to rot - Ash has little rot resistance but that shouldn't matter that much for a rubrail.
Ability to hold a scarf joint - About the same.
Ability to hold a countersunk screw hole - About the same.
Appearance - A matter of preference. Teak & mahogany is certainly a classic combination.
Maintenance - About the same.
Cost - Mahogany will certainly be more expensive but you are not talking about enough wood for this to really matter.
Weight - We're talking ounces here. If weight matters that much then do you really need rubrails?
Karma - See appearance. On the other hand there is much to be said for using a local wood like ash rather than something hauled up here from Central America!
Others? - An important factor could be which one is available locally in long enough pieces (with nice straight grain)

I don't think you will need green wood to make the bends you are talking about, and if you use green wood then you will need to let it dry before you finish it and you risk drying defects developing as the wood dries. To figure out if you can make the bend without breaking the wood try bending a 2-3' long test piece. The piece laid on the deck will obviously be the critical one. If you are running into problems some hot water poured on a towel wrapped around the piece of wood will help quite a bit on a thin piece of wood like this. Make sure the grain is straight and that there is no runout.

My only concern with using a 3/8" thick piece of wood is that you may have to put a lot of fasteners into it to get it to lay flat without using glue, which, as others have noted may not be so desirable. Some experiments with short samples should give you a good idea of where you stand on this issue.

Note: I don't really like white aak for this sort of thing because I've seen it turn black if the finish gets rubbed of, water soaks into it, and it doesn't get attended to promptly...

11-13-2003, 04:33 PM
Originally posted by Bruce Hooke:
Note: I don't really like white aak for this sort of thing because I've seen it turn black if the finish gets rubbed of, water soaks into it, and it doesn't get attended to promptly...Assuming Bruce meant white ash when he typed "aak", he voiced my sentiments exactly. I've seen ash on canoes get the ugly black ich thing. That's why I suggested sassafras as a substitute for ash. Assuming of course that it is visually appropriate for the particular boat in question.

I still have to wonder about the 3/8" dimension. 17' canoes get larger rails than that. But, it's not my boat. Try a mock up first with cheap wood. Bump into it. See how it holds up.

Carl Simmons
11-14-2003, 01:58 PM
Dave Nickels in Fenton, Michigan used to make
wooden Lightnings (19') with Mahogany Rub rails. I
a set for my Lightning from him. I believe he may have some left. I believe they are just long enough for your boat. Here is a picture of a portion of them on the Lightning:


Bruce Hooke
11-14-2003, 04:06 PM
Aaak! Ooops! What I meant to type was white OAK.

My family has a nice old cedar on oak rowboat built in Maine about 50 years ago. For many years much of the oak was vanished but during a "low" period after my grandfather died the boat was not well maintained and the oak developed a lot of black stains. Subsequently we decided to paint most of the oak, which gave the boat a slightly less yachty look than it had originally, but varnished oak with black stains looks like hell...

Bob Smalser
11-14-2003, 04:26 PM
The tannic acid in oak reacts with a number of things to cause stains.

Sanding, an oxalic acid slurry applied followed by a darker stain before revarnishing will improve the appearance.

Bruce Hooke
11-14-2003, 05:29 PM
Originally posted by Bob Smalser:
The tannic acid in oak reacts with a number of things to cause stains.

Sanding, an oxalic acid slurry applied followed by a darker stain before revarnishing will improve the appearance.Thanks. I have heard about techniques along these lines. We decided that given the degree of staining and the work involved in getting rid of it, it would be better to simply switch to paint...

Bob Smalser
11-14-2003, 05:37 PM
I paint all my DF, too...and most of everything else, for that matter...seems to look fine on the water next to bright-finished boats.

I prefer to do things other than annual brightwork maintenance. I like varnished interior trim against white-painted panels....and that's about it for me.

Doug Tutty
11-16-2003, 01:03 PM
This may be totally off base, since I don't have experience with your kind of boat. I've seen a lower rub rail made of whatever looks good about 1-2" wide with a half-round grove running down the middle. In the grove was placed an appropriatly sized piece of laid rope, tacked by the back strand. It stays clean, looks good, and rubs don't hit the finish on the rub rail itself. The type of rope is chosen to complement the rest of the boat.