[Public-list] repower options

[J Bergquist]

Dear List,

 

My venerable atomic 4 which served me well for 3 years (and several previous
owners for more years than I know) has finally bitten the dust. Don't ask.
The motor is not going to be resurrected. I am considering repower options.
I have the following thoughts:

 

1.	My operating profile includes 95% of the following mission: use the
motor to get away from the dock, put up the sails as soon as possible, go
sailing, and use the motor to get back to the dock. Total usage: 1 hour per
trip. 
2.	Of the remaining 5% of motor usage, 80% is: motor all day when
trying to get somewhere under time constraint and no wind. 
3.	The remaining 1% of total usage is: use the motor to stabilize the
boat during conditions too extreme for safe sailing. 

 

I would like to entertain all repowering options which will allow successful
operation of my boat within the defined operating envelope. I have
considered the following possibilities:

 

1.	Repower with a rebuilt atomic-4 or rebuild my own. 
2.	Repower with a diesel prime mover. 
3.	Repower with an electric prime mover, with the following
sub-options:

a.	No onboard power generation (must recharge using shore power)
b.	Onboard solar power generation
c.	Onboard solar and wind power generation
d.	Onboard diesel, gas turbine (yeah, baby), or gasoline power
generation

 

My defining parameters are weight, space, safety, range, resale value, cost,
and ease of use/maintenance. 

 

I am wondering if anybody out there has opinions about this. I am sure that
many of you do have opinions. Mostly, I'd like to know if anybody reading
this list has an electric prime mover, and if so how much power do you have?
The numbers for electric power are MUCH smaller than for internal
combustion. I am just wondering if I can drive the boat through the water
anywhere close to hull speed with a 4 HP electric motor. Also, what kind of
weight and size do your batteries take up, and what is the range? 

 

Secondarily, who has recently repowered with diesel and how much power did
you install? What is the consensus on how much horsepower is sufficient? I
have heard numbers ranging from 13 to 25. I recognize that the propeller
choice is also a variable. Without getting too deep into propulsion calcs,
I'm just wondering what people have found to be sufficient in terms of
power? 

 

Is there anybody who has ever heard of a gas turbogenerator installed in a
sailboat of our size? Mostly, I'm just curious. I can't find any
manufacturers of such a thing, but it seems to me like it might be a good
option.if you could deal with the volume of air, the exhaust temperature,
and the noise level. There are some sites that I found which show use of
helicopter gas turbines for various applications that might correspond with
the size and space constraints of our boats..but they are definitely nothing
close to a complete package including gearing and a generator set. 

 

Any other thoughts from folks who have recently repowered? I have heard one
recommendation in favor of a beta diesel. They seem to be very nice, but
also very expensive. I've read a lot of articles about the choice between
rebuilt A4 and new diesel. I know one fellow owner who has a westerbeke, and
another with a universal. Anything else y'all want to add? Any particular
testimonials or criticisms? 

 

Eternally grateful,

 

J Bergquist

Calliope #287