T&T: Heat

[Francis X Lawlor]

Tom,

There are two factors that are very important for your consideration  
of heat in the winter on the Chesapeake:  the size and the insulating  
qualities of the boat..  We are south of you off the Choptank River.   
We have a 40 ft. boat and have successfully installed a hot water  
system with an aux system for use underway in cold weather.  Our  
primary heating system is hydronic with the diesel fueled Hurricane  
boiler  of 45,000 BTU heating capacity.  A full week of midwinter  
heating here uses about 9 gallons of diesel.  Our boat has  
exceptionally good insulation with about 2 inches of foam in the  
cabin structures and more in the hull.  We do however lose lots of  
heat through large areas of single pane glass esp. in the Pilot  
House.  We have lived aboard during late season trips south on the  
ICW and have maintained heat while at our dock during winters when I  
was doing extensive work at the dock.  The Hurricane unit is small,   
reliable, quiet.  It functions with a  main thermostat in the aft  
saloon and individual thermostats in the blower units in each cabin.   
With 750 amps of usable 12 v. battery capacity,  the system functions  
very well at anchor overnight (no gen aboard).  Our secondary system  
consists of a 25,000 BTU truck heater plumbed into the main engine  
(an 85 hp Perkins) and located in the galley just aft and down from  
the Pilothouse.  Underway this produces ample heat in the saloon and  
up in the Pilothouse in severe cold weather conditions so that we do  
not run the Hurricane at such times.  The interior volume of a 40 ft  
powerboat is such that anything less than about 40,000 BTU will be  
insufficient in low temps.  Calculations made while we were building  
ruled out the sort of arrangement you are considering.  The hot water  
tank idea generally will not work considering heat losses in hoses,   
etc.  The heating elements on 120 v. shore power will not be able to  
keep sufficiently hot water circulating.  This disappointed me but  
our solution works just fine.

Frank Lawlor   (HOBO)

Comments, thoughts and opinions sought:

I need more heat in the winter.
Am planning to add another dedicated 20 gallon hot water heater like the
one I have now for general hot water (Seaward Products, 120 volt).
I would power this with shore power when at the dock and connect it to
the engine for hot water when under way.
A manual valve would keep from heating the engine with shore power
electricity (expensive where I am, 25 cents per kw).
John Deere is ok with this and the connections to the engine are ready
to go.
I need a circulating pump (probably check with Depco for 24 volt) and
three radiators (undecided here), one each for salon, kitchen / dining /
helm and one for the master bedroom.
I would use heater hose to hook it all up. I think the heater hose used
in the boat now is rated for something like 550 degrees and is very  
stout.