Based on our recent experience, if you don't want to be tied to a genset or a huge solar array, the best thing to do is use the Frigoboat type of system with evaporator plates and Danfoss compressor, with keel cooling. Cost and power efficient. You do need to build a well insulated box, if you want to keep the power consumption down. House systems are efficient on AC power - new models anyway - but the boxes themselves are very short on insulation. Regards – Steve

We use deionized water in the tank. Size is usually a function of what structure is handy. To fit in a couple of the keel coolers with building space is going to take at least a couple of square feet of top. If the tank is eight to ten inches deep, you should be OK. And yes, we’re very pleased with the system.

I would look up Danfoss on Google. On their website they have extensive data on power vs btu. Steve

Hi Thomas: Moving the batteries aft is a change in trim of 24,000 foot pounds (15′ times 1600 lbs). You can easily calculate the change in trim (the stern will go down a bit) if you find out the foot pounds required to change your trim one inch. As a wild guess, if this figure was 7,000 foot lbs, the change in trim would be 24,000/7000 or 3.4″ The designer of your hull can calculate this figure for you in a couple of minutes, or you can do it yourself once you have the data. Most cruising boats end up pretty heavy, and tend to trim by the bow, so my guess is that this stern down trim will not be a big problem, and may even things out if you are presently bow down. One way to test this would be to add some sand bags, or a dinghy full of water, to the correct spot on deck and visually look at the water line. – Steve

Hi Ute: There is no easy answer to your question as it depends upon how the boat you have is built. For example, the bigger engine will require different engine beds, a larger exhaust line, bigger prop shaft and prop, heavier support on the prop shaft, different prop shaft bearings. The engine will be much larger, and the layout in the engine room may have to be changed. If all these things were to occur, it would cost you a lot more than the simple cost of buying a new engine, and the boat with the 220HP engine at $25K more would be a bargain. However, it is possible that the boat with the 85HP Perkins was built with engine beds large enough to accommodate the bigger engine, and than the rest of the running gear was built for the 220HP engine and just a smaller diesel was installed. In which case it would be simple to change. If you want a larger engine, I would get a firm quotation from a boat yard for doing an installation – and then you will know for sure. Good Luck – Steve

Hi Bev: Tough problem. The first thing I would do is find a company that cleans up after fires and toxic spills and see what they suggest. There are some soaps which work better than others. You will probably have to soak the areas as diesel will get into tiny crevices, much smaller than what you can wipe with a rag. The other thing to try is an ozone generator. These work well with odors. Good Luck – Steve

Hi George: We are using the keel coolers, but inside the boat in a special aluminum fresh water tank (where the bronze cooler is isolated from the surrounding aluminum). While I have not used these before, they should operate the same as the sintered metal bonding plates which we have used on all our fiberglass designs for many years. You will have to periodically clean the coolers from marine growth, but otherwise it should be fine.

As to electrolytic corrosion, the risks with this should be the same as with any other through-hull. From my perspective, it looks like a very good approach for a fiberglass boat. Regards – Steve

Hi Jim: No easy answer to your question. Seventy-five gallons of water would be considered a lot by most of the boats cruising 25 years ago. But if you were to lose the watermaker early on a long passage, you would want to be well versed in living frugally – and have the ability to wash with salt water and/or catch water off your awnings and decks. Another question is the reliability of the water maker and genset.

Then there is the definition of your 500 mile range – at what speed and wind/sea state? Can you extend this by slowing down a bit?

Another factor is the boat’s sailing ability, especially in lighter winds. The better the sailing qualities, the less diesel you require.

Finally, have you looked into a fuel (or water) soft type of tank – assuming you can secure it well? Might be that the best trade-off is to switch over a water tank to fuel as you’ve asked about, and then carry a bladder tank in case extra fresh water is required.

Note: Make sure you keep the fuel and water tanks physically separated. Having a water tank with an internal divider will not work with diesel and water! – Steve

Hi Brent: I have not had any direct experience with Whispergen. However, the sterling engine concept has fascinated us for many years. The ability to get DC power, domestic heat and hot water from one unit is very enticing. Kelly Archer installed one of these on a boat he recently built and it does work. It remains to be seen how reliable the unit will be – but they seem to have a good reputation in New Zealand. – Steve