I suspect that you are correct. Our boat came equipped with 2 8D house batteries
and a 4D starting battery. The starting battery was actually a deep cycle gel
cell and worked perfectly well. (85 HP Perkins) I replaced it with a Group 30
starting battery for the savings in size. Unless your engine is hard to start and
requires alot of cranking Incidently, the previous owner accidently started the
engine in -20F temps using the deep cycle battery!


Doug
s/v CAllista

"Roger Long" wrote in message ...
Is there any reason to consider using dual purpose or a one starting, one deep cycle set up with a 20 hp Yanmar diesel? I would think the starting loads on the small engine are low enough that two deep cycle batteries would do fine.

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Roger Long