Strainer Question

Stinkpot

Commander
Joined
Dec 2, 2011
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Location
Cape Cod Canal
Boat Make
36' Calvin Beal
I've had this strainer below on my Calvin Beal for 5 years now. After the 2nd year, I had to drill out the threads in the bronze body and re-tap them for larger screws because they were "stripped". Turns out the bronze body was succumbing to the effects of galvanic corrosion since the stainless screen is fastened to the bronze body with stainless machine screws. Now, I have to drill & tap 8 NEW holes in new locations because the original holes enlarged so much that I can't go any bigger. I dunno, seems like a poor design to me. Why wouldn't they have used SiBr screens and screws? Has anyone else noticed this with this type of strainer? If I switch to SiBr screws, all I'll be doing is changing the dissimilar metal interface to the screen-to-screw points; won't that cause the SiBr screws to waste away? What if I used maerlon screws and ensured a thick coat of paint on the surface between the screen & body? Any other ideas? Thanks.
Stinkpot

strainer.JPG
 

Pedlyr

Captain
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Aug 31, 2011
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Location
Southern RI
When I work with aluminum and steel or other dissimilar metals I usually make a galvanic isolator out of vinyl plastic or rubber. Like a gasket. Especially on aluminum boats with steel sea chest valves.

I also use something called Penetrox on all my hardware which will not eliminate galvanic corrosion but slows it down. When I was fishing, used it on the deck plates/hatch dogs when I rebuilt them. Sometimes there was wet steel, lead, aluminum or bronze components bolted together. Depending on the make.

I like to use Penetrox on my wiring as well. I thought at first it might promote galvanic corrosion because it is for conductors. But it seems to help. Probably cause it displaces moisture.

Penetrox A Aluminum Copper Anti Seize Seez
 

Stinkpot

Commander
Joined
Dec 2, 2011
Posts
256
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Location
Cape Cod Canal
Boat Make
36' Calvin Beal
Well I made up a gasket to fit between the bronze strainer housing and the stainless screen and I'll switch to bronze machine screws to hold it in place; we'll see what happens next season.

Thanks!
 

BillD

Admiral
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Sep 1, 2011
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Location
Portsmouth NH, boating out of the mighty Merrimack
Boat Make
25 Terry Jason with Cummins 370 power
My 1996 31 Blackfin has the same intake scoops.

When I bought the boat in 08 had to remove the screens.

S Florida boat in water year round 11 seasons.

Tremendous growth over the scoops and metal ware.

Surprising, no issues removing the SS screws.

I've had the screens off a couple of times.

FWIW,

Bill D
 

El Mar

Admiral
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Westbrook, CT (The Asshole State)
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Bryan
Boat Make
43 Tiara Open DDEC, GradyWhite 268 Islander, 18 Donzi Classic, 15 Boston Whaler Sport ETec 60

Blacktide

Commander
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Oct 13, 2011
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Location
Long Island
Boat Make
Northern Bay 36
I have a zinc on the aft side of the scoop on mine. No serious corrosion on it at all
 

traditions

Rear Admiral
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Oct 9, 2011
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Location
mid coast maine, muscle ridge channel
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38 Holland
second the zinc,drill and tap on the back side.We dont see many of that type strainers,mostly the one piece cast bronze ones.I think they are designed to go on rond side forward,but very rarley see them that way,mostly put on like a scoop.
 
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