Oil Filled Rub Rail?

[SV Miss Fe]

My Boat is all steel and almost rust free except for a rusty drip coming from the port and starboard rub rails. During the survey the surveyor noted periodic metal pipe caps coming through the hull and thought that the rub rail might be filled with oil and that these were the access points. Has anybody seen this before? I'd like to repair the rust coming from underneath the rub rail but without knowing how it was made its difficult to come up with a strategy. Any help as to how this was built or how it can be fixed would greatly be appreciated.

[Pauls]

You'll need to give more detail. You mention "rust coming from under the rub rail". Is it fastened to the hull? In which case how could it be oil filled? Or is it a welded half-pipe?

[Lepke]

As a former boat builder and commercial fisherman: it was common to use rubrails in steel boats as a return line for hydraulics. Rub rails usually were schedule 80 (thicker walls). It's bad enough to have an accident, worse if the EPA is involved.
We didn't use half pipe, but full pipe cut into the ribs and skin. Also, the keel usually was made to cool engine water.

[Nicholson58]

I have heard of and seen similar treatment for keels where the keel may be filled with scrap steel and then oil filled. This prevents freeze and rust. Seems unlikely for a rub rail. Are the stains coming from pin-holes in the weld joint? I suspect so, find and repair the holes.

[SV Miss Fe]

I really wish I knew how these things are fastened that would make a fix a lot easier to figure out. I can say that I haven't seen any fasteners. I can also stick a knife blade up between the rubber and the hull a good bit. I can't see any welds. To my knowledge and I have halfway decent documentation on the boat (excluding rub rails of course) no hydraulic systems were ever used.

Obviously I'd like to stop the rust with as little damage to everything as possible. I'm running out of ideas that don't involve destructive investigation. I guess I could pop off one of the end caps on the inside and at least see what if anything is inside it.

[unclemack]

Guessing there's a steel backing bar that the rub rail is fixed to - and the caps inside the hull are covering the nuts that fix the rail backing bar.

And that whoever foamed the inside did the owner a favour by making sure the nuts could be found by just prying off the caps.

[unclemack]

Just blown up your exterior photo - looks like they've used black silicone sealant all around the edges of that D-section rub rail - could be a problem removing it. Silicone isn't good on boats really.

Depending on the type of fixings and how they've used them you could end up having to completely remove & refit the rub rails, maybe even repaint the topsides.
Nuts/bolts/screws might be rusted, seized & might break.
Maybe try undoing a few, see how it goes.

Starting from scratch I'd probably have wrapped butyl tape around each fixing between the rail & the hull. No silicone.

Butyl can be shaped like plasticine and doesn't set, harden or crack, but seals very well if used carefully in the right application. I use it for deck fittings on a steel hull, never a leak.

ps. The backing bar I referred to previously is usually but not always inside the hollow "rubber" D-section. The moulded, rounded end sections are bonded (glued) on, at least on the ones I've seen.

[GILow]

Originally Posted by unclemack

Guessing there's a steel backing bar that the rub rail is fixed to - and the caps inside the hull are covering the nuts that fix the rail backing bar.

And that whoever foamed the inside did the owner a favour by making sure the nuts could be found by just prying off the caps.

+1. Sounds exactly right to me. We have a similar deal D section rub rail and I have been desperately (and unsuccessfully) avoiding this very method of attachment. I will be posting the results of my last half arsed attempts to attach the darn thing soon.


Sent from my iPad using Cruisers Sailing Forum

[ausnp84]

Have you tried taking a cap off yet? I'm intrigued as to why the previous owner would have left those areas unfoamed.

As said above, it looks like the rub rail / D section has been attached to the hull but moisture has found it's way beneath, causing rust. Not a big deal - if you can remove the inside caps and *carefully* cut away the D section, you're in business. Clean the steel beneath, repaint it if needed, then refit the rub rail with PU sealant (Sikaflex 292, 3M 5200, etc). All my deck fittings go on with the stuff and it doesn't leak - if applied properly.

If the inside caps won't come free well, you might just have to cut away the rub rail anyway. You could always dig a bit beneath where the rust is coming from and refill with PU sealant, but that's only really a stop gap to treating the real issue.

n

[JPA Cate]

GILow,

If you have glued on rubstrakes, getting them off will be a pita. Thereafter, carefully clean them, and the hull--we're aiming for totally leftover-free here--, and then clean again before sealant. If you want them to stay on for fifteen yrs. or so, use 3M5200, if you can keep them in place for the week setting up period.

Ann

[GILow]

Originally Posted by Ann T. Cate

GILow,

If you have glued on rubstrakes, getting them off will be a pita. Thereafter, carefully clean them, and the hull--we're aiming for totally leftover-free here--, and then clean again before sealant. If you want them to stay on for fifteen yrs. or so, use 3M5200, if you can keep them in place for the week setting up period.

Ann

Ann, we did glue them, and therein lies a most interesting observation.

We used some special combination of glue and primer, endorsed by 3M as perfect for our situation. We followed the instructions to the letter (though I confess the primer was slightly past the best before date when we used it). We also drove 14g screws in from the inside into the rubber itself, to resist shearing force.

And within two days of fitting the rub rails this bonding method was tested, I thought, to the most extreme conditions possible. I had left my set of steel boarding steps on the finger of the pen, in the usual place. But the new wider rub rail caught the boarding steps as we came in, and 17 tons of boat was tilted to the side as the steel boarding steps snag, rotated, and jacked the boat up by the rail. And the rail held!

I felt both pretty smart and pretty stupid, not a bad combo.

So a year later, you can imagine my surprise that after bashing through some really heavy seas for 6 hours, I discovered the downwind side rubrail had pulled the screws and torn the glue joints from the bow, back to the first porthole, about 6 feet in total. Thankfully the rub rails are indestructibly strong, so I was able to lash them in place in a lattice of ropes, but now I have to think of something better.

And I am determined NOT to have the sequence of plug holes that usually apparent with these setups.

Tonight I measured up some stainless steel self drilling screws that I am planning to drive into an aluminium strap inside the profile, to see if that proves stronger. If it works, then I will be able to leave the existing glue points alone, and simply add the strap to the rest of the rail that remains firmly attached.

Fingers crossed.

Matt

[deblen]

Link to catalog of plastic/rubber rub rail profiles FYI:

http://store.hamiltonmarine.com/brow...ail/2,545.html

http://www.integritymarinecorp.com/default.html

Cheers/ Len

[Cadence]

Originally Posted by SV Miss Fe

I really wish I knew how these things are fastened that would make a fix a lot easier to figure out. I can say that I haven't seen any fasteners. I can also stick a knife blade up between the rubber and the hull a good bit. I can't see any welds. To my knowledge and I have halfway decent documentation on the boat (excluding rub rails of course) no hydraulic systems were ever used.

Obviously I'd like to stop the rust with as little damage to everything as possible. I'm running out of ideas that don't involve destructive investigation. I guess I could pop off one of the end caps on the inside and at least see what if anything is inside it.

I am not sure I even understand it? Are you sure the rail was not fastened, welded, to the hull with a metal that rusts? I seriously double hydraulic systems are running through the rub rails. Out of curiosity does the rubber rail look like it may have rubber bungs in it. Studs could have been welded to the hull with nuts under bungs. I maybe out in left field? Just a thought.

[unclemack]

"Tonight I measured up some stainless steel self drilling screws that I am planning to drive into an aluminium strap inside the profile, to see if that proves stronger. If it works, then I will be able to leave the existing glue points alone, and simply add the strap to the rest of the rail that remains firmly attached."

Hi Matt,

stainless fixings in alloy are known to seize up. That might not be a problem in your application, I don't know.
Monel is usually recommended for fixings in masts etc., no idea if you can get self-tappers though.

[dannc]

I have read of voids being filled with oil to prevent rust.

There was a recent post on the Attainable Adventure Cruising website, which is subscriber based, that discussed an oil filled toe rail.

https://www.morganscloud.com/2012/02...steel-part-ii/

Sounds like this has worked for them for a couple of decades.

Later,
Dan