Caulk the new rub rail?

When Installing a new aluminum rub rail the question arises whether to caulk it.

Argument A: A line of caulk along the top contact would prevent dirt from building up inside the rub rail and gradually passing through it, streaking the hull.

Argument B: You are wasting your time caulking it. Any caulk will itself yellow and capture dirt. The streaks you see on the hull won't be stopped by any rub rail, and dirt does not have to weep inside the rub rail to create the streaking effect.

As far as I can see, the factory rub rail was not caulked along the top. It has a thick bead of white caulk where the aluminum contacts the flange. I don't know why.

Advice or opinions welcomed.

Hi,
I wondered about this five years ago and decided to caulk. The caulk has lasted
well and keeps the hull cleaner. I have no regrets and would do it again. But it needs to be done carefully as a sloppy job would look ...well. ..sloppy.
Frank

Frank Langer said:

Hi,
I wondered about this five years ago and decided to caulk. The caulk has lasted
well and keeps the hull cleaner. I have no regrets and would do it again. But it needs to be done carefully as a sloppy job would look ...well. ..sloppy.
Frank

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Does it help keep the streaks down? If so, I think we may caulk too.

Rub rail woes.

Fellas, Years and years and years ago a good, tired of the streaks, finally solved the problem, for a while at least. He cleaned and scrubbed the rub rail of all the chalk, etc, let it dry accordingly and applied some sort of single part white marine enamel to the masked off rubber. It's been many years since he's sailed with us to Catalina and I haven't checked of late, but I do know that it held up for more years than he ever expected. That might be something to consider in this case as well. Glyn Judson, E31 hull #55, Marina del Rey CA

Glyn Judson said:

Fellas, Years and years and years ago a good, tired of the streaks, finally solved the problem, for a while at least. He cleaned and scrubbed the rub rail of all the chalk, etc, let it dry accordingly and applied some sort of single part white marine enamel to the masked off rubber. It's been many years since he's sailed with us to Catalina and I haven't checked of late, but I do know that it held up for more years than he ever expected. That might be something to consider in this case as well. Glyn Judson, E31 hull #55, Marina del Rey CA

Click to expand...

I feel like this has come up before, and someone recommended buoy paint. I poked around a little, and I see Vinylon at http://www.seattlemarine.net/products/crab.html - the Vinylon name seems familiar as I roll this around, but I don't see white listed as a color. Maybe worth a call. There are other buoy paints out there, but this name jumped as perhaps what had been referenced in past threads. It might be a starting point. Another source to check for buoy paints is Hamilton Marine - www.hamiltonmarine.com - here's white: http://store.hamiltonmarine.com/browse.cfm/paint-buoy-white-qt-for-pvc-buoys-115108/4,34397.html

Regarding replacement of the aluminum rub rail, the Taco A11-0511 does seem to fill the bill. It covers the flange and is a hefty extrusion with highly polished anodization, more robust that the factory original.

Transporting and manipulating these slender 20' sections, which arrive at your local West Marine in mailing tubes, is an interesting project, especially on the roof of a Prius. My half-mile drive to the boat was at 20 mph. Next time I will mount a long 2x4 on the roof racks for support. I bought one section for proof of concept, and have now ordered three more. Yes, the rub rail measures 30' 10", so four 20' lengths are required at $275 each. Wherever you find these long Taco products, free shipping is important; otherwise extremely expensive.

A great lot of dirt was trapped under the old rail. I believe the massive amount of caulk used was designed to head that off. Most of the old caulk adhered to the inside of the rail. The bits still stuck to the hull were quite hard to get off. I'm not planning to cleanse hospital-style the remaining caulk, as the new bead will just go over it. Dunno what to use, maybe 4200. (No, Sikaflex 291 sounds better).

Today I will fill the old screw holes. It doesn't look like the flange will have to be faired or ground much, if at all.

Here is what Sikaflex has to say about the purpose of backfilling rub rails with caulk:

Rub rails and fenders are designed to protect the hull of a vessel against damage. These act as a bumper to absorb impacts and scrapes, and the more elastic these are, the more effectively they perform this function.

The elastic behaviour varies according to the type of material used, so the shock-absorbing performance of the rub rail can be significantly improved by the use of an elastic adhesive joint. This provides maximum protection to the hull.

Rub rails of timber, PVC or polyurethane can be securely bonded to marine hulls using Sikaflex-292. The resulting elastic joint helps to absorb most of the shear and tensile stresses to which they are subjected when a vessel is docking or casting off.

If rub rails are secured with screws, a similar effect can be obtained by backfilling the rail profile with Sikaflex-291; a highly elastic polyurethane sealant. As well as absorbing torsional stresses, this technology also seals the screw holes and prevents water or dirt from getting behind the rub rail.

I'd like to do this job in the spring ... if we ever get there, up here in Boston

Christian - what are you using for end caps, bow and stern?

At the moment it looks like the present cast-alum end caps will serve, with a little grinding. I am more worried about how the Taco rail will look. I think the chances are good it will succeed, but as we know the rub rail is right in your face as you approach the boat, and it needs to look perfect to justify itself. Soon enough we'll see, I guess.

Can't wait to see your finished project.

I am wondering if butyl tape could be used as a sealant ... I've had great results with just about anywhere else I've used it.

Now West Marine reports that my rail order, back-ordered until March 24, is now expected on April 24. Grrr.

I wonder if one of those container ships still waiting off Long Beach has my shipment on board....

35 MK3 rub rail

Hi All, I have been working on the replacement of the old aluminum rub rail this winter and have chosen a rail produced by Barbour Plastics in MA. We will cut down the depth of the rail by 1/4" to 3/8". I have not decided what adhesive will work best but a thought is to use 3M VHB tape on the upper lip of the rail then a thin bead of some sort of non yellowing caulk. The VHB tape should seal the top of the rail from water and dirt intrusion. As far as dirt dripping/ staining the hull the best way to solve that issue would be to cut a drip edge on the underside of the rail so water/dirt going over the rail will hit the drip edge and not touch the hull but drip away from the hull. I am not sure I will make that cut as the stainless strake may do the same job. Here is a photo of the sample rail I choose. We should be installed in the next few weeks.
I will follow up.

Carl

Finished rub rail job using Taco product:

http://www.ericsonyachts.org/infoexchange/entry.php?280-Ericson-32-3-Aluminum-Rub-Rail-Replacement

Well done

Christian,

It may seem like a thankless task, but, we all appreciate the work, outcome and especially the information.

Great job!