This post is going to save someone’s as$. The information is invaluable.
We have a SeaRay 280 Bowrider, 1996, but I am sure the info applies to newer models. Someone (not me, I know better!) unwisely left the batteries on when they left the boat. Which of course is always a mistake on a boat. Batteries are dead.
And what compounds the problem is that the batteries are underneath the hydraulically lifted engine cover. Which needs battery power to open. And which weighs a ton and is linked to hydraulic lifters which effectively prevent you from just lifting it by hand. Oh crap. (This is a strange boat — large for a bowrider, small for inboard/outboard engines, any bigger and it would have a shore power connection which would solve my problem, but this boat does not).
The SeaRay owner’s manuals are useless (though you can download them all here to your heart’s content). Clearly they don’t expect boat owners to actually ever look at the engine. So I called Lake Union Searay Redmond branch — nice people, very helpful. Apparently there is some way to reach through the oil check hatch and remove pins from the hydraulic lifts to allow you to muscle the hatch cover up — but it would require an intimate knowledge of the engine compartment since you are basically reaching around blind, the hatch is just large enough for your arm and no more.
Here is the key trick though. If you cobble together a 12V source (battery, charger, whatever) with a cigarette lighter adapter, and plug it into the cigarette lighter 12v port at the helm (which is normally used to provide power to 12v devices), the electricity will flow back into the boat and allow you to use boat electrics — hatch cover, etc. Completely undocumented and SeaRay won’t give you the parts to do it, but the service guys admit it will work.
So I got a $21 small riding mower battery. Went to Fry’s and got lighter adapter hardware. Wired them together, plugged it into the cigarette lighter, and pop the breaker went in the boat. Disconnected, switched polarity, reset the breaker, and tried again. Voila!!!! Hatch cover openers worked, I can now get at the batteries and either recharge or replace as needed.
Additional warnings and tips:
* the cigarette lighter adapter from Fry’s had 16-20 gauge wire, not sure what. Whatever it was, it is not enough for longterm use — the wire got hot to the touch. So get the job done and get it out of there.
* Before I went to Fry’s, I tried used an old cell phone car adapter I had lying around. I cut the phone connector off, stripped the wires. This was clearly never going to work for two reasons. One, the wires were incredibly small, I am guessing 26 gauge. They would never have been able to carry the power. Two, the lighter head of the adapter is full of rectifying/transforming electronics, stepping down the car 12v voltage/high amperage to something the phone can use. Clearly I would not be able to stuff 12V/moderate amp signals back through this.
Good luck, hope this helps someone.