373 MarineAir Water Intake Broke Off

May 28, 2025
13
Beneteau 373 New Bern, NC
I was priming and cleaning out my AC via a hose from my dock and the Y connection from the seacock to the filter gave way. It was corroded and almost closed up with corrossion. So now I'm left with a stub on the seacock to unscrew and try and replace that connector. The boat is in the water. I'm concerned with trying to do this in the water. Yes, I have plugs and could use to plug the boat from the outside for security. Has anyone else had this issue or done this?
 

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Mar 6, 2008
1,515
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
Since the valve is closed, you should be ok. Use 2 plumber's crescent wrench to open the upper part while holding the valve part in place.
It appears that the broken part is not bronze and should not be on the boat. It has rusted and eventually broken. Replace them with bronze parts only.
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
24,753
CAL 35 Cruiser #21 moored EVERETT WA
It is not the gunk in the pipe. It is the degradation of the connection fittings them selves. See the arrows.

Leads me to guess that the connectors were brass not bronze. That you have galvanic corrosion happening and the zinc in the metal has been leached out,

I would be concerned that the pipe used to form the through hull is likely also affected. I would not do this repair in the water. I would have the boat hauled, the repair can be done overnight in the slings. It can save some money with some marina’s. On the other hand, if one fitting is being done perhaps all should be inspected and replaced is needed. If the through hulls are brass then all are suspect.

Use of non-bronze fittings. Fine for home use, dangerous for below water marine use.
Signs of galvanic corrosion. Change in metal color.
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Jan 11, 2014
14,169
Sabre 362 113 Fair Haven, NY
This is what happens when boat parts are sourced from the hardware store plumbing section and then metals are mixed, SS through hull, galvanized steel pipe fittings, and brass hose fittings. Only luck kept the boat afloat.

The through hull is probably compromised, it needs to be replaced sooner rather than later. The risk of breaking the through hull while removing it is great. Haul the boat and expect to spend more time fixing it than you planned, don't plan on a short haul. Plan on replacing it with a flanged seacock and through hull. Groco makes nice one. The better quality Marelon non-metallic seacock probably won't fit in the space.