Marine Batterys

Amazingly, you can arm curl these batteries easier than a 6 pack, and yes, they have a quick punch to start engines.
They are not designed for that. In a engine starting roll I compare them to Capacitor starting devices.
That quick quick punch and wait for the next. They can not continuously turn over an engine on a cold and stormy night.

They won’t work on my old tub.
Starboard engine needs a shot of laughing gas and a finessed crank when cold out. ( below 60 )
Lol, my two 8Ds power /start everything…
Good old Ocean ( Pacemaker) ingenuity.
BUT, it works . ( helps to have a fresh new generator to keep them charged ) . Lol.

Block heaters are our friend.
60W trouble light under the pan a few hours is a good friend also.

IF they're rated as a starting battery or dual purpose. If not the BMS (Battery Management System) will not allow them to put out enough amperage. Lifepho batteries is what you want for safety. Most are rated as deep cycle only.

A group 31 lithium will put out enough starting power as your 8D.

That is good info to know. Makes it worth considering for weight and size.

Looks like this power cat fire was caused by the lithium batteries. A chicom built boat and lithium… what could go wrong!

https://loosecannon.substack.com/p/firefighters-suspected-her-lithium

and of course there was this one, earlier this year

https://www.***************.com/yacht-news/visionf-82-yacht-flagship-fire-miami