Cruisers & Sailing Forums - View Single Post - Shore Power

ViribusUnitis · 03-07-2009, 22:21

I've been looking at boats in the ~40 foot LOA range. I'm wanting to have it set up for a family of 3. My wife, our kid, and me.

Well, my major issue was with is the semingly very common 30 amp cord up to the task. Just a quick math told me that 1 microwave, 1 water heater, 1 a/c system and all the 12V stuff on some of the boats is too much. The 12V loads could be quite large between 12V refer system, heads, lights, and god knows what else. Expecally if start up inductive loads are added up. Microwaves, and a/cs being bad about that.

I was thinking that the boats really were not designed to use the a/c or the water heater. Or that it was a somewhat poor design to use a 30 amp cord, but have an 8k generator set onboard. It would seem to my mind that if you've got around 8000 watts of generator, you should have a shore cord capible of handling around 8k.

You seem to indicate with with proper power mannagement that it probably is. Apperently the start up loads arn't long enough to effect the plug, or the shore breaker. That would seem to me to be a poor design compromise. It would involve pulling some rather high amperages, on rather hot days. I would expect that a better compromise would be a 30am 110/220 plug, which isapperently uncommon. A 50 amp 110/240 plug would certanly be overkill on a ~40 foot boat. (50 amp at 240 = 120,000 watts!)

03-07-2009, 22:21	#5
ViribusUnitis Registered User Join Date: Jun 2009 Posts: 40	I've been looking at boats in the ~40 foot LOA range. I'm wanting to have it set up for a family of 3. My wife, our kid, and me. Well, my major issue was with is the semingly very common 30 amp cord up to the task. Just a quick math told me that 1 microwave, 1 water heater, 1 a/c system and all the 12V stuff on some of the boats is too much. The 12V loads could be quite large between 12V refer system, heads, lights, and god knows what else. Expecally if start up inductive loads are added up. Microwaves, and a/cs being bad about that. I was thinking that the boats really were not designed to use the a/c or the water heater. Or that it was a somewhat poor design to use a 30 amp cord, but have an 8k generator set onboard. It would seem to my mind that if you've got around 8000 watts of generator, you should have a shore cord capible of handling around 8k. You seem to indicate with with proper power mannagement that it probably is. Apperently the start up loads arn't long enough to effect the plug, or the shore breaker. That would seem to me to be a poor design compromise. It would involve pulling some rather high amperages, on rather hot days. I would expect that a better compromise would be a 30am 110/220 plug, which isapperently uncommon. A 50 amp 110/240 plug would certanly be overkill on a ~40 foot boat. (50 amp at 240 = 120,000 watts!)