Aluminum Wire and Hose Routing Clamps

[wspitler]

Just purchased a 2007 330 that had all aluminum clamps in the Gen compartment. All were severely corroded, broken, powdered, etc. Also had a plain steel clamp holding thre Gen fuel pump that was corroded thru. Does Grady put aluminum on new boats? Seems to be cheap as compared to other fittings. They appear to be original. Not up to Grady standards for sure. Replacing all with S/S. :huh

 

[seasick]

Was the genset factory or installed later? I wouldn't expect aluminum clamps from the factory. I wouldn't expect aluminum from anybody. Chrome on steel maybe.

 

[wspitler]

It was all factory installed I assume. I bought it as a 1 owner boat with all the manuals. I had heard of it in another forum as well.

 

[wspitler]

As it turns out, GW was using aluminum clamps, at least through 2007. I talked to them recently and they have since changed to stainless steel (adel) clamps. They sent me all new s/s replacements, no charge and apologized for the corrosion. They had attached them to the structure with stainless screws which exacerbated the problem with bi-metallic corrosion issues. Once again great customer service with no excuses for a previous weakness.

I suspect there are a lot of older boats out there with the problem and just don't realize it. Try inspecting an older boat's generator compartment/bilge and I'm betting you'll be surprised at the condition of the clamps! GW comes through again!!

 

[BobP]

Aluminum angle can be used with stainless screws, plenty of alum angle is used in boats. Stainless angle is very heavy and expensive.

Saltwater (electrolyte) is the problem, just have to use a treatment on contact surfaces or caulk screws where sw will be present. Same happens with alum float on trailers and galv bolts, in saltwater usage.

Generators are used plenty in FW boats and much more in RVs, perhaps standardized hardware.

Remember, your outboard motor is made of an aluminum alloy incl block and head, not stainless, and manages to have a prop shaft and gear box and prop made of stainless and other metal against the alum alloy housings.

 

[wspitler]

I don't believe these clamps were even anodized and the rubber inserts had a tendency to collect moisture under the rubber. The ones that were in the lower part of the bilge were mostly gone to powder. The clamps supplied with the genset were stainless.

 

[DaleH]

Aluminum angle can be used with stainless screws, plenty of alum angle is used in boats. Stainless angle is very heavy and expensive.

Saltwater (electrolyte) is the problem, just have to use a treatment on contact surfaces or caulk screws where sw will be present. Same happens with alum float on trailers and galv bolts, in saltwater usage.

Generators are used plenty in FW boats and much more in RVs, perhaps standardized hardware.

Remember, your outboard motor is made of an aluminum alloy incl block and head, not stainless, and manages to have a prop shaft and gear box and prop made of stainless and other metal against the alum alloy housings.

Stainless steel in direct contact with aluminum or other less noble alloy will ALWAYS be subject to "galvanic corrosion", where the ions in the less noble material will precipitate out, thus weakening it. Galvanic corrosion is exacerbated in the presence of an electrolyte, of which saltwater is ideal! Such effects can be lessened and completely eliminated by taking steps to insulate the less noble material from the SS. One can used nylon or other insulating washers or material or even adhesive-lined heatshrink used on bolts, which is what I do when fastening hardware onto my tin skiffs using Ss hardware.

One notable product that accomplishes this is Tef-Gel, but any marine grease or gasket sealing compound also accomplishes this too. On my lower unit bolts, if I don't do the full waterpump/impeller service every 2-years (for example small OBs), I'll at least pull the LU bolts 1 at a time; clean them, regrease (gasket sealing compound is what most OEMs recommend in this appliation) and re-install to the proper torque. I'll even do this on new motors to parts where I expect to have to take it apart in 5 or more season down the road, e.g., trim motor housing bolts, etc.

But note in your example that the propshaft and gears are isolated from direct contact by the bearing carriers. Bottom line, any SS used with aluminum should be properly protected, or the results can be disasterous at worst, or cause stuck and broken bolts at best ... which makes any reapits a beyatch to effect!