Gib'Sea 302 anode change needs engine out?

[rex_seadog]

Gib\'Sea 302 anode change needs engine out?

I am hoping that forumites can provide some advice to my friends who are in a 3-way syndicate with a Gib'Sea 302. The hull anode never shows any sign of wear and according to a marine engineer this is due to the anode not being connected to the engine. Apparently access to the anode from the inside is nigh impossible and the solution is to remove the anode and reposition it. But, and a big but, this will require removal of the engine at a total cost of something like £800! What I fail to understand is why the existing anode needs to be removed. Why can't it be left where it is and a new anode simply fitted in a more convenient position and connected to the engine?
Another thing that puzzles me is why Gib'Sea, apart from failing to make the necessary connection, positioned the original anode in such an inaccessible position. The engine is believed to be the original Yanmar. One further point is that the anode fixed around the prop shaft (i.e. between the stern gland and the P bracket) wears away quite rapidly so perhaps this has been providing all the protection.
A lot of this information is about 3rd hand so forgive me if its a bit vague. I know that an obvious retort is to ask the engineer for a more detailed explanation but they are new to the boat maintenance game and are simply trying to get another independent opinion.

Another point raised by one of the other syndicate members is that as the toilet plastic inlet/outlet seacocks were recently replaced by brass ones do these need any anodic protection. News to me as our brass seacocks are still OK after 20 years although as we only have an outboard engine perhaps that makes a difference.


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[chriscallender]

Re: Gib\'Sea 302 anode change needs engine out?

Sounds like someone is trying to rip you off, I too can't understand the need to remove the old anode (and presumably the studs that it is bolted onto) provided that it is in good condition - except that a future owner might be a bit confused why there are 2 anodes it would remove a tiny bit of extra drag. Unless someone else knows better.

Brass seacocks are a different issue. The problem with brass is dezincification - brass is an alloy of copper and zinc. Over the years in seawater it will loose its zinc & hence its strength. Connecting brass to a zinc anode won't help too much with this problem since you can't use zinc to protect zinc. If brass is used at all then they ought to be replaced regularly (every year or 2?) and a better answer in the long term would be to use bronze seacocks, although the inital costs are much more but it is not the kind of thing you want to make savings on.

I suspect that there are differing opinions on whether bronze seacocks would need connecting to the anode - in the case of my boat they are not connected and I do not have a corrosion problem (surveyor was happy with them in June 03) but it might depend on what else you have underwater.

Anyway bronze seacocks will last a long time with proper maintenance - I'm pretty certain that if your seacocks have lasted 20 years they were bronze and not brass. Are you sure that this is not what has actually been fitted? Are they operated by a lever or by a wheel (gate vales are often brass and operated by a wheel similar to what you often have in the central heating or hot water system in your house).

Chris

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[rex_seadog]

Re: Gib\'Sea 302 anode change needs engine out?

Chris

Thanks for your comments. Yes, indeed, I think I should have said bronze. Mine are the Blakes valves operated by levers and, as an aside, need a 110 degree turn to shut them off. (Learnt this only after several years of wet bilges/bunks etc. See my previous thread on this subject). I'll check with my friends to see exactly what valves they have had fitted.

Regarding the anode - my thoughts entirely. Sounds as if someone is trying to rip them off.



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[Talon2]

Re: Gib\'Sea 302 anode change needs engine out?

Can you get to the conection at the engine end of the cable. This could be where the fault lies.
Have you got internal anodes in the sea water side of the engine and if so it would be interesting to know if they are working.
I am a motoboater and with outdrives it seems that you can never have enough anodes. We have 3 on each drive.
I would suggest that if your original anode is not working just leave it be and put a new one in an accesable place with a real good connection to the engine.
Problem should be solved.

<hr width=100% size=1>Keith

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