Catalina went to 4D &8D back in the late 90's. Even the Catalina 310, a 31 footer, had two 4D's. They do this because in the volume they buy the 4D's are cheap bang for the buck. The extra jumpers for the 6V's, labor and customer confusion lead them to not use 6V batts even though they surely could be made to cost less than two 4D or 8D batts. I spoke with Gerry D. at Catalina about their choice and "large batteries sell" and are "impressive to people buying boats." I guess they are if you are somewhat clueless.... I'll take four 6V batts over any combination of 4D or 8D and I won't be needing Stryker spinal implants either...;)

Catalina was using Exide Nautilus Gold batteries and despite the claims these are not a true deep cycle battery nor do they perform as such. Most 4D and 8D's are not true deep cycle but rather hybrid starting/deep cycle. Lifeline's 4D & 8D are deep cycles as are the 4Dd batteries made by Dyno Battery but most are not. Ours lasted as long as we owned the boat but were fading rather fast in just two years..