Jim wrote:
On my trawler my present house battery bank consists of two 8Ds, my
starting battery is a 4D.

The 8Ds are ready for replacement. I'd like to go with golf cart
batteries.

Trojan T-105 are available from several sources. (6VDC, 200+AH)

My guess is $60 max, probably closer to $50 in quantity.

Lew