Bunks,Electrolysis and Aluminum Boats....

[Seafever]

I have an aluminum boat.
It sits on carpeted wooden bunks.

Every time it comes out of the chuck I hose the boat and trailer down with fresh water.

The fresh water does not penetrate right into where the boat is sitting on the bunks.

The other day I had the boat off the trailer on another issue and notices some pitting in the hull where it sits on the bunks.

The trailer is galvanized but the brackets that hold the bunks on look like some other metal and of course the hull is aluminum.

So I'm thinking over time there may be some galvanic reaction going on there.

Don't really want to go to rollers.......but the carpet on the bunks holds water for quite awhile like a sponge.

Was thinking those grooved plastic bunk add-on strips would let more of the water out (the ones that EZ loader makes). They will fit any wooden bunk.

Or some kind of heavily grooved palstic strips that drain easy.

I see something called a channel bunk......what are those?.....better than fixed bunks?

My boat doesn't weigh that much.........don't know if rollers on aluminum hull are good idea.....


Any suggestions?

 

[trophywife]

i have had the same problem,,do you have a properly painted bottom? i also added zincs to the front end of my boat... let me know what ya do... i am thinking uvm strips...

 

[Seafever]

No...I've never painted the bottom......yet.

First thing I did today was put some zincs on the boat hull.......they are in a place that does not penetrate the hull, so no through-holes.

I'm going to put a couple zincs on the trailer too......right up near the bunk mounting brackets on each side.

I have UHMW pieces laying around.......but I'm not going to use those because they are very slippery and I don't want the boat moving around on the bunks.

I'm thinking some kind of highly, deeply grooved plastic or rubber pieces.

My trailer is a RoadRunner...on their site they don't show much for spare parts.

But on EZ Loader's site they show these pieces of grooved plastic add-ons in the parts section.

Something like those or maybe I'll make my own.

 

[Battle Bay]

I have a 24ft North river with a ez-loader with the plastic bunk slides, love them boat goes on ad off the trailer no problem. I like that they keep the boat and the carpet apart. I have no problen wit the boat moving at all once it is on the trailer thats where is stays.

 

[Sculpin]

Seafever
I would definately recommend getting rid of the carpet. The moisture it holds is causing the corrosion. Also if the wood is pressure treated there are chemicals in it that will make the corrosion even worse!. Take the carpet off and put on those slick bunks with the grooves or better yet install the UHMW strips. I have fixed 3 riveted tinnies now that were eaten right through the hull because of carpeted wood bunks. On a thicker hulled aluminum vessel it is the same but will just take longer. You will see discoloration first then pitting will start.

If you saw my trailer rebuild thread I put the UHMW strips on and I have not had her slide or move at all since. It is also surprisingly not that slippery when launching etc. and is about the same as the slick bunk material I had on there previously.

Cheers,
Sculpin

 

[Sitkaspruce]

Sculpin

What are UHMW strips?? How do I check my boat when it is either on the trailer or in the water??

Now I am worried about my boat, always on the trailer when not in use.

Cheers

SS

 

[Sculpin]

Sculpin

What are UHMW strips?? How do I check my boat when it is either on the trailer or in the water??

Now I am worried about my boat, always on the trailer when not in use.

Cheers

SS

You running carpeted bunks Ken? If so I would jack up the two back corners until the hull lifts off the bunks and take a peek. There is a good thread over on Aluminum Alloy Boats in regards to this problem with carpeted bunks and aluminum hulls. I'll try to find the thread and post it up. Like others have posted, roadrunner and other trailer makers offer slick bunk plastic covers with grooves in them. I would highly recommend replacing the carpet with this material or the UHMW material that is available at most plastic shops. It's just a wear resistant type plastic similar to cutting board material.

Cheers,
John

 

[High Velocity]

Another plastic material that may work well is puck board. It's extremely tough and with a good table saw, relatively easy to work with (an extra pair of hands helps). I've purchased two 4' X 8' X 1/4" sheets for approx. $70/sheet. One sheet was used to build a 4X 8 cutting table which has been used extensively for big game. We've also built a few skid plates for atv's with it. I know it's available in black, red, and white. Not sure on other colours.


Sent from my iPad when I should be fishing.

 

[Sculpin]

Here is one of the threads.

http://www.aluminumalloyboats.com/viewtopic.php?f=5&t=1654

There are more. You don't have to be a member to look around all though I highly recommend joining if you own an alloy boat. Just like any forum you have to wade through the bs to get to the good stuff. There is a ton of good stuff on that board.

Cheers,
John

 

[Statler]

Sculpin,

What thickness would you recommend? Is a 1/4" thick enough and would you recommend going the full width of the bunks or say 3 strips an 1" wide along the entire lenght? Also what about running 1/8" grooves in the strips to help with drying?

Thanks,
Kevin

 

[Sculpin]

Sculpin,

What thickness would you recommend? Is a 1/4" thick enough and would you recommend going the full width of the bunks or say 3 strips an 1" wide along the entire lenght? Also what about running 1/8" grooves in the strips to help with drying?

Thanks,
Kevin

I went with 3/8" thick if I recall and yeah I would go full width and put some grooves in it. I didn't put grooves in mine this year but I will look at her in the fall and see if there are any issues and may put them in over the winter.

 

[Seafever]

Thanks Sculpin .....you are a fountain of inspiration.....

 

[Statler]

Thanks Scuplin, I ordered 1/2" black UHMW. It was only $10 more than the 3/8" and I should have it this afternoon. Thanks again.

 

[Seafever]

Sculpin:- I think I'm in the market for a new boat after taking a good look at the corrosion. Not bad in some spots but in others it's dicey. Don't want to be out on the chuck and spring a bad leak.

Wish I'd known what I know now years ago.

My boat got popped off the bunks when I pulled out of Kennedy Lake Park on the weekend. Stopped and fixed it. But that's the only time I've ever had a really close-up look at where it sits on the bunks. Maybe it was a blessing in disguise because if I'd never had a look at it, it would just be getting worse until failure.

The hull is 12 years old (not all that old really.....I know guys with aluminum boats much older than that with zero corrosion problems)and has sat on the bunks for all that time when it's not in the water.

I was thinking about getting a new boat anyway.

The old girl had a good run........caught lots of fish in her.....lots....

In earlier part of thread you said you'd fixed a few riveted tinnies that had been eaten clean through.

I'm just sort of curious as to how you did that......the hull is not thick enough to weld.

Did you cover it over with fresh strips of sheet aluminum and then rivet the hell out of them?

Just curious is all........

 

[Sculpin]

In earlier part of thread you said you'd fixed a few riveted tinnies that had been eaten clean through.

I'm just sort of curious as to how you did that......the hull is not thick enough to weld.

Did you cover it over with fresh strips of sheet aluminum and then rivet the hell out of them?

Just curious is all........

Yup, did just that with some 3M sealant thrown in there for good luck lol. They actually turned out looking good and I haven never heard back from the owners.

 

[Halilogger]

Any place in Campbell River that sells UHMW

 

[spring fever]

Haliloger I just purchased UHMW and had it shipped from BC plastics-there is twice as much as I need. I have 4 pieces-51/2 inches wide 6 ft long and 1/2 inch thick which I want to sell for 140 bucks. I'm staying with rollers on the front Mike

 

[Broadwater]

How did you fasten the plastic to the bunks?

 

[Seafever]

You have to watch it when you drill UHMW......drilling a hole right through it is not too bad.....BUT...if you try to put
a "countersink" in it by using a slightly bigger drill....the drill will "bite' real quick and before you know it you are too deep.

UHMW tends to BITE on drills easy.

Don't countersink it with a bigger drill bit.......use an actual beveled countersink bit.

At least that's the experience I've had with good ol' white UHMW.


Also:- Aluminum does not rot the same way as steel. aluminum tends to get "pinhole"
deterioration. These pinholes will work their way right through even though it does not look all that bad. Steel tends to flake off in bigger chips.
When they first came out with aluminum SCUBA tanks, this would happen to some.
An otherwise perfectly good-looking tank would show leaks when hydrostatically tested. Steel SCUBA tanks you could usually see the rot-out when inspected internally as part of the test....but not aluminum tanks.

 

[Sculpin]

UHMW tends to BITE on drills easy.

Don't countersink it with a bigger drill bit.......use an actual beveled countersink bit.




Also:- Aluminum does not rot the same way as steel. aluminum tends to get "pinhole"
deterioration. These pinholes will work their way right through even though it does not look all that bad. Steel tends to flake off in bigger chips.
When they first came out with aluminum SCUBA tanks, this would happen to some.
An otherwise perfectly good-looking tank would show leaks when hydrostatically tested. Steel SCUBA tanks you could usually see the rot-out when inspected internally as part of the test....but not aluminum tanks.

Very good advice on using a proper countersink bit. Don't ask me how I know lol. I have 4 extra holes in my side guides do to trying it with a bigger bit because I misplaced my countersink bit at the time. I thought I'll just go really slow...........wham right through!

Aluminum is different for corrosion issues for sure. Since I joined that AAB site I have learned quite a bit about the stuff. It is actually recommended to to take the mill scale off or etch the sheets before building a boat. Barely any builder does this however. There is a guy from Alaska named Kevin that posts quite a bit on that board and has some lengthy posts about it. He has net skiffs that he built 20 years ago that live their entire lives on the beach and he say's they look as new as the day they were built.