keel fin

Corrosion, Paint, Through Hulls, etc.
honestcharlie56
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Re: keel fin

Postby honestcharlie56 » Tue Jan 03, 2017 10:13 pm

aluminum anodes in salt water?
1990 Marinette 32 Sedan Flybridge "Hubba" Lake Charles, LA
Twin Chrysler 318's

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Busia
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Re: keel fin

Postby Busia » Tue Jan 03, 2017 10:22 pm

Yes, aluminum anodes in salt water.
BUSIA
located in Ketchikan, Alaska. Gods country
32 foot Marinette express. (no fly bridge)
twin 350 Crusader (Chev 350) engines
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Fastjeff
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Re: keel fin

Postby Fastjeff » Wed Jan 04, 2017 6:15 am

If you've ever run a, say, 20 foot IO boat, then you'll appreciate that keel! My 32 footer tracked dead straight, hands off the wheel, as we negotiated miles of no wake zones. By comparison, a 20 footers with IO drive waddle all over the place, even with constant steering corrections.

Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington

hoohaah
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Re: keel fin

Postby hoohaah » Tue Jan 10, 2017 10:04 am

Keep the keel fin, it came from the factory
Wally from Hoohaah 39' also
[img][urlwww.]gldocks.com[/url][/img]Wally D
39' Marinette twin Volvo diesels
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DougDoty
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Re: keel fin

Postby DougDoty » Fri Jan 13, 2017 9:48 pm

I have a 39 Sedan and that keel is original and necessary, tracking is good and sorted out from the factory, you can feel good about keeping it original and the anode system is as well is optimized from the factory.
1984 39 Marinette Sedan, " LIBERTY ONE " Warsaw KY, 440 chryslers, Westerbeke 9.0 kw , 1 3/8" shafts 93 1/4" long and 19x22 dyna quads or, 19x20 DQX's 38.5 MPH GPS best.

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Re: keel fin

Postby Butchel » Fri Jan 13, 2017 10:49 pm

The yard guy here in Rockport insists that the keel fin should be seam welded back in place to prevent electrolysis from attacking the hull in the poorly insulated spaces between the welds and that the sacrificial aluminum anodes should be welded to the fin or the bottom of the hull to insure good contact. He says the hull will not be protected otherwise and the stainless steel bolts will set up galvanic action with the anodes. Apparently, the hot salt water of the gulf requires extra precaution.

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Busia
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Re: keel fin

Postby Busia » Sat Jan 14, 2017 2:42 am

He is full of crap. Totally full of crap. Just do it like the factory did, and I would find somebody else to do it.
BUSIA
located in Ketchikan, Alaska. Gods country
32 foot Marinette express. (no fly bridge)
twin 350 Crusader (Chev 350) engines
1:1 Borg Warner velvet drive transmissions
Closed cooling (antifreeze in the engine)
Proud to be retired IBEW

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bcassedy
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Re: keel fin

Postby bcassedy » Sat Jan 14, 2017 8:40 am

Your yard guy is either well intentioned but woefully mis-informed -or- trying to sell you on work your boat doesn't need.
The welds that exist between the hull and the keel are TOTALLY sufficient for protection. If these are the original welds, they were done in such a manner as to never fail to provide continuous connectivity.
Many members of the forum use the stainless steel method of bolts (nuts and washers) to attach/hold the anodes to the keel. It's not a perfect system. Water (fresh/brackish/salt) will get between the anode and keel. BUT... the protection there is fine. The anodes will be sacriced, as is the intent. You shud pull the boat (as you would need to do if the anodes were welded to the keel - which you shouldn't do), unbolt the anodes (replace if needed), clean them up if good, clean the keel surface, and then bolt back on.
Think of it this way...
You can pay the yard guy to weld the anodes on and then pay him again to do the regular mainteance/checking, and then pay him to weld the old (or new) anodes back.
He'd have to run a watertight weld around the anode to ensure there'd never be any corrosion (and subsequent potential loss of galvanic protection). Such a watertight setup would be time consuming. That isn't gonna be cheap!!
-OR-
You (or he, if you trust him) can use the tried and true methods of clean up and bolt on. It's quicker, just as reliable (when part of regular "out of the water" maintenance), and far, far more economical.

Bill
Last edited by bcassedy on Sat Jan 14, 2017 8:50 am, edited 2 times in total.
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Fastjeff
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Re: keel fin

Postby Fastjeff » Sat Jan 14, 2017 8:46 am

For heaven's sake DON'T weld the anodes on! Bolt them on, as the rest of the world does.

That guy's a nut job.

Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington

barkleydave
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Re: keel fin

Postby barkleydave » Sat Jan 14, 2017 9:52 am

Aluminum Cruisers Inc knew what they were doing. Bolt them on. I have never seen any galvanic reaction between the SS bolts and the anodes or hull. Now if you are still concerned here a couple of things you can do to ease your mind.

1. Mounting surface of keel Must be clean and bright.
2.You can use silicon or whatever to coat the SS bolts to isolate them from the hull.
3. Run a bead of 5300 around the anode to keel joint to help reduce water penetration between anode and keel.

I have done all of the above and it worked fine. I also have done none except clean contact between anode and keel and saw no difference in the result. While the boat is on the hard check you anode condition clean them and most important check continuity between the anode and the hull. If good leave them alone.

I like Fast Jeff use a mag. hung over the side anode while at the dock. I have done this with this boat now for 12 years. It not only keeps my hull protected...I have seen little deterioration of the Keel, rudder and trim anodes. DO NOT USE A mag. anode in salt water. Hauled 18 months ago and just cleaned, checked done!

Boatzincs.com has the correct anode strips and over the side anodes for our Big M's.

http://www.boatzincs.com/hanging_anode_aluminum.html

Here is the link for the Strip anodes for our Big M's

http://www.boatzincs.com/marinette-bar.html

safe harbors
dave
1987 Marinette 29 FB Sedan
Retired Boat Accident UL and USCG trained investigator
Retired USCG Captain