Moved cranking battery up front - what size fuse?

[Cubman]

I have a 1648 with a 70hp tiller motor. I moved the cranking battery up front to help with weight distribution. There is about a 15ft run of 4 gauge cable. I would like to add a fuse at the battery in case something rubs a hole in the insulation of the 4ga cable. What style and size fuse should I use?

EDIT: Or what style and size circuit breaker should I use?

 

[Bob Landry]

I don't think I have ever seen a fuse on a cranking battery, at least on the boats I work on. The large gasoline and diesel motors are fed through a battery cut-off switch in the event of a runaway starter, but I don't know about outboards.

 

[krawler]

I would start at 80 amp either fuse or breaker.