Only had a brief look at the web site and didn't see too much information on them.
1. You need to find out if they are suitable for short term high loads. Engine start or anchor winch.
2. How do you charge them, As in, can your existing charge system (240Vac Battery Charger, Alternator or solar) perform to there requirements or will need to be modified to do so.
3. What is their physical size compared to your existing setup. Will they fit in your existing battery space.
There could be more costs involved than just the price of the batteries.
