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-   -   Martec Prop Cotter Pins (http://www.sailnet.com/forums/gear-maintenance/53105-martec-prop-cotter-pins.html)

rperret 04-03-2009 03:22 PM

Martec Prop Cotter Pins
 
I've got a martec folder on my S2. Last year I replaced the pins - getting new monel pins from martec (at a cost of $10...).

Question, do these props really need monel pins v. stainless? Anyone out there using stainless cotter pins on their martec? Monel pins are impossible to find and i don't really want to spend yet another $10 on new pins.

I haul every year so would put in new stainless pins annually.

Thx.

sailingdog 04-03-2009 03:31 PM

Ask yourself "What is the worst that can happen if that cotter pin breaks from crevice corrosion...or the cotter pin rots the prop" and then see what repairing that is going to cost you, and figure out how many years of cotter pins that repair would pay for... :)

That's why I have AAA Plus for my car and a TowBoat US membership for my boat. :)

JimsCAL 04-03-2009 04:05 PM

Martec STRONGLY advises against using stainless cotter pins to avoid electrolysis with the bronze prop. Bite the bullet and get them.

rperret 04-03-2009 04:19 PM

ah..so they did not advise me of that when I called them last year.

so help me understand if electrolysis is an issue - how come the stainless shaft does not appear to have any electrolysis issue?



Quote:

Originally Posted by JimsCAL (Post 470460)
Martec STRONGLY advises against using stainless cotter pins to avoid electrolysis with the bronze prop. Bite the bullet and get them.


cnc33voodoo 04-03-2009 04:33 PM

dude, its $10.:rolleyes:

rperret 04-03-2009 05:31 PM

yeah yeah - not the cost - need them quickly...

actually now found a local source....after an hour of web surfing...

Quote:

Originally Posted by cnc33voodoo (Post 470476)
dude, its $10.:rolleyes:


Fstbttms 04-04-2009 12:17 AM

Quote:

Originally Posted by rperret (Post 470468)
so help me understand if electrolysis is an issue - how come the stainless shaft does not appear to have any electrolysis issue?

Because the shaft is likely not made of stainless steel, but rather Monel, just like the cotter pins.

brak 04-04-2009 12:24 AM

Quote:

Originally Posted by rperret (Post 470468)
ah..so they did not advise me of that when I called them last year.

so help me understand if electrolysis is an issue - how come the stainless shaft does not appear to have any electrolysis issue?

Shaft is big, and it is also towards the boat from the prop. So the electricity flow is from shaft to prop to water. This prevents much corrosion occuring at shaft. Pins are small and they are between prop and water, so since stainless is less noble than bronze, pins will act as sacrificial anodes and may dissolve relatively quickly.

sailingdog 04-04-2009 06:46 AM

IF the cotter pin acts as a sacrificial anode and corrodes away, like the zincs do, what is keeping your prop in place????

Fstbttms 04-04-2009 10:45 AM

Quote:

Originally Posted by brak (Post 470647)
Shaft is big, and it is also towards the boat from the prop. So the electricity flow is from shaft to prop to water. This prevents much corrosion occuring at shaft. Pins are small and they are between prop and water, so since stainless is less noble than bronze, pins will act as sacrificial anodes and may dissolve relatively quickly.

This doesn't even make sense.


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