- Earlier this year there was a similar discussion about Forespar's Marelon and bronze seacocks.
Marelon seacock failure
You might find this an informative read if you're really interested in finding out about Marelon thru-hulls and seacocks.
1. A significant portion of cruisers who say they never have had a problem with their seacocks, really do have a problem and never know it. Until it'd too late or they're just lucky.
2. The Forespar 93 series Marelon valves weakest point is the handle. In particular, the nylon nut that the handle bolt screws into.
3. Marelon is nothing more than Dupont Zytel nylon. Nylon is hydroscopic and will lose around 60% of its strength in water
. In about 3 months the threads on the nut will become soft and have little strength.
4. The Catalina
Owners Association has issued a warning about this issue. The design of the 93's internals are a serious failure point. If the nut and handle pull out of the housing, which has happened a lot ball can't be closed.
5. The OD of the 93 thru-hull is oversized so you would have to significantly enlarge the hull
6. The 93 1/2" and 3/4" seacocks use the same thru-hull. The same holds true for the 1" and 1 1/4" and the 1 1/2" and 2". If you need a 3/4" flow rate capacity you need to install a 1" unit, a 1 1/4" capacity requires a 1 1/2" unit and if you ned a 2" capacity flow rate you're out of luck.
7. If you find you don't like the Forespar 93's and want to get rid of them, you'll need to glass in all the ports
because the Forespar 93 thru-hulls sizes have a non-standard oversized OD.