Bunk Trailer and Galvanic corrosion

[Nat]

Need a little help finding the easiest solution to this problem
The boat is stored on the trailer (it gets a very good fresh water bath after every use including the trailer) and we have what appears to be an area were salt is trapped against the hull

There are no staples or screws touching the hull, but there are galvanized lag bolts screwed into the bottom of the treated wood bunks just a few inches away from the area affected, Could the hull be grounding thru the wood to the galvanized bolt?

I was thinking about putting trailer glides on the front bunks, but depending on the material they are made from, They also may have a problem with trapped salt

I scraped most of the white powder off(looking for staples) before taking the pics
there was alot of white poweder buildup







this is the area from below




any ideas for a solution ?

[Nat]

update

The lag bolts are just shy of penetrating all the way through the bunk board
the tip of the bolt is about 3/16" from coming thru


Do you think my hull would be pitted?

[pjay9]

When i bought my roller trailer the other option was the new style bunk, which looks to be a plastic material, maybe you could switch out your old carpet boards or recover your boards. I have even seen some old old trailers with the decking material called TREX, I think, used as the bunks, issue with that is it needs lots of support as it in not strong like a wood bunk. Hope I gave you some ideas. Capt PJ

[Nat]

Does anyone know if these are okay to use on aluminum




http://www.basspro.com/webapp/wcs/store ... rentPage=0

[welder]

Nat , go to west or the similar and get the PLASTIC bunk covers and problem solved . The plastic covers the bunks.

Of course when you install the plastic DO NOT disconnect the bow strap until your in the water or you will find out how heavy these boats are.

[dbzbrand]

Hey Nat,
I would presume it is more a moisture issue with the trailer bunks, we (Aussies) use carpet covered bunks on glass boats and usually polyethylene/teflon strips on alloy boats. We have had issues on small tinnies where they have a plywood floor covered with carpet and where the carpet rolls around the ply edge it sits up against the boat sides/chine and causes corrosion issues. Bunks offer the best support for your vessel and the right plastic will be much easier launching.

[JETTYWOLF]

I'd love to hear Jay Perotta's take on all this....TOPIC. Nat, have you asked him about it??????

Does the new 34 Rock Salt have carpeted bunks?? But then again, the bottom is painted. But then again, doesn't he leave a BLM in the water all summer with no bottom paint too?

Every single "SAFEBOAT" I see the Coasties using have spaced out plastic/Teflon on their trailer bunks.
Which I always believed to be for launching/retrieving......because,

-How many Coasties does it take to launch/retrieve a 28-30 foot Safeboat????

"I've counted as many as 12 standing there guiding the truck and then yelling to the boat pilot."

[Jay Perrotta]

Hi Nat,

Yup. I think this is the third time we've seen this. One was a 26' boat on a '"lift" on Long Island, the second was a 26' in Rhode Island. Not sure exactly what the cause is - a rot treatment on the wood? unique carpet composition? If it was every boat that is trailered and kept on a bunk trailer it would be easier!

The two boats that had the issue went to the poly bunk glides and the problem was solved. Separating the alloy hull from the moist carpet/wood is the solution!

As Captain George already said - there is a learning curve to how easily the boat then slides - don't unhook then start backing down - the boat may well slide right off!

Best...

[JETTYWOLF]

Thanks Jay,

That's what I was thinking too. Since I don't see any problems with mine, either...(Mine's kinda buffed real clean, from the constant drive on and off)


You're my go-to guy. Everyone needs one.

I hope that's not any undo pressure.

[Occams Razor]

Hello All:

Have never posted on here before so I hope you find my info useful. I had this very same problem with my 26CC. I believe Jay meantioned a 26 in Rhode Island. That would be me. Occams Razor is one of the few 26 cc Black Lab hulls in my imeadiate area. It gets more attention than than I would like to admit. I like to keep things clean. Anyhow I noticed this very same problem after about a year. Being a ham radio operator and knowing how different metals and liquids can produce DC current I had a hunch. Rite after I pulled the the hull I rinsed it off thououghly as always and after sitting overnite to dry I measured the voltage between the galvanized trailer and the bottom of the hull. This was done with the bow hook undone to isolate the hull. Well after drying off for twelve hour I measured just over 530 Microvolts. Just over 1/2 a volt . Not much but we can see what that causes ! I contacted Jay and we spoke of the problem so he could help future bunk trailer users. As noted previously trailer slides will eliminate this problem. I found this company www.surfixinc.com
that has very heavy duty trailer slides of custom lenghts. They come complete with stainless mounting hardware. Make sure you seal the screw recesses with caulking when mounted. After two years no problems, measureable voltage. Hope this helps some of the question as to how this happens.

[welder]

Mr Razor, That is what we are lOOking for , GREAT find and great post .

WELCOME to AAB and enjoy.