Wed Jul 21 2021
Any boat loses performance when it’s loaded up, just like any helicopter. At light weight acceleration and top speed are much more impressive, but we aren’t racing out here. We are battling the elements, but that’s what foul weather gear and a diesel furnace are for. Catamaran sailboats seem to suffer performance losses with increasing weight faster than monohulls, or at least that’s the general perception. As well, bridge deck clearance is reduced which results in more slamming in rowdy seas, an unpleasant experience for the crew.
Still, there are just some things one shouldn’t skimp on. Yes, everyone has a budget to observe and buckets of money for capital outlay up front versus ongoing operating expenses, but my rule of thumb is “you can pay now or you can pay later, but you WILL pay.” It turns out that when we’re in our home countries where we have vendor relationships and access to boat stuff, it’s a lot easier to equip our vessels and generally a good bit cheaper. If you wait until you get to a foreign country to belly up to the bar and finally pay for that thing you should have just bought before you left your home port, you’re going to enjoy big shipping costs, import fees, time delays, lost shipments, etc. Since we ain’t getting any younger, Isabel and I aren’t keen on that time delay thing, and we are also mindful of the cost of all this.
Lots of folks want to know how much solar is enough, how small a house battery bank they can get by with, what’s the cheapest water maker to buy and operate, how long can they stretch the time between engine or gear oil changes, do they really need to carry a spare whatnot, etc. Rich Boren sold us our CruiseRO 30 gallon per hour water maker, and Rich is fond of saying, “Nobody ever complains about too much solar power or too much house battery reserves, too much fresh vegetable and beer refrigeration or too much fresh water.”
After cruising in Mexico for 3 years generally in brilliant sunshine, we were doing great with 400 amp hours of LiFeP04 house batteries and 920 watts of solar power. So what? We were heading to the South Pacific, first French Polynesia then on to Tonga, Fiji, New Caledonia, Vanuatu, New Zealand, Australia, and onwards. Isabel has cruised some of those waters and can tell you how cloudy it can be.
Sometimes I actually listen to my wife, and even more rarely heed her suggestions. After considering our energy use in sunny Mexico and what we might encounter going forward, I did that engineering thing with a pen and a napkin (generally done while sitting alone at the bar eating dinner on a business trip) and decided we needed more. Excess solar. Excess house battery capacity. We needed to optimize everything for performance and efficiency. The only nod to energy efficiency we didn’t make was on the water maker. Our CruiseRO water maker is an AC powered unit, and is about one third as efficient as an energy recovery unit like Spectra or Schenker. Still, the CruiseRO was already installed and paid for. It had performed flawlessly, is an extremely simple and reliable piece of machinery, and the customer support is superb.
So we have 1440 watts of solar (4 panels), each with an individual MPPT controller to optimize system performance in partial shading conditions. We have 720 amp hours of LiFeP04 batteries monitored and protected by a battery management system that Stan Honey describes in a white paper on his website. We have high output small case alternators with external rectifiers controlled by programmable regulators.
It’s cold, it’s been cloudy and foggy, and with a little help from our friend the Honda generator but mostly from our solar and house battery capacity we’ve kept the lights on, the autopilot and instruments working and the furnace running. Maybe its not for everyone but it’s sure working for us and JollyDogs still sails well in light airs.
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