Roger Long wrote:
The consensus from the owner's forum for my boat on emergency starting
a 2 cylinder Yanmar seems to be this:

For emergency starting with dead batteries, carry one of the following
on board. A Westmarine emergency battery pack or an NFL linebacker
properly trained and housebroken.

So why not just carry a two batteries instead of the emergency pack?
You can get AGM starters from an auto shop at about $100. With the
low self discharge you can jut keep one in reserve for the weekend.