Extra Range under Power

I am considering our next major cruise from NZ/Oz up through the Red Sea, and our charging/motoring/fuel strategy. I have calculated that we get about 1 mile/liter at our normal cruising speed, possibly a bit more. This gives us about 1200 miles with current fuel capacity. Across the Pacific we pretty much motored all the way to Galapagos–no wind. Sailed all the way to Marquee’s, but then motored all the way to Tahiti, and got low on fuel and had to reload from a ship in the Tuamotus, which was very messy and expensive. So I am investigating how to get some more capacity. Ideas:

Glass a tank in on the port side of the lazarette. The area is hard to get at anyway so won’t be too much of a loss.

Glass a tank in on the stbd side behind the current tank in that ‘dead’ area below the compass/steering box.

I reckon, without actually measuring the boat as we are currently skiing in South Island (life’s tough, eh), I guess I could add about another 300+ miles. Which would have life a lot easier in the Tuomotus, for example.

I KNOW ITS MORE WEIGHT!!!! but do you have any other ideas?

I am also considering swapping my homebuilt DC generator for the Balmar, with watermaker add-on. Is this what you have? How does it work out? The literature says it will set its own speed/charge rate, how does that work out?

Also our batteries are getting real bad and I’ll probably change them, did you go for the lead acid Tudors as we have, or the more sophisticated dry cell ‘I can’t remember what they are but not gel type or lead/acid’ new types.

Any advice gratefully received–and probably written about, we start a ‘Masterclass’ series for YW in October!

Hope cruising is going well–Regards, Brian

Hi Brian: The first suggestion for better range for me would be to make sure the prop is polished, bottom clean, and then reduce speed to a speed length ratio of 1.0 to 1.05 (eight- to eight-and-a-half knots for you).

Assuming you are doing all of the above (just a slight surface roughening on the prop will cost you 10% to 20% in efficiency), the next step is to make sure the fuel tanks are being filled. I know this sounds simplistic, but if there is any fuel trapped in the breather line it will restrict what you can get into the tanks. Trace the breather hose and make sure it slopes upward along its entire length, and that there are no dips or hollows, which will trap fuel.

Assuming all of the above is where it should be, adding fuel with a glassed-in tank can be tricky. Diesel has a lower viscosity than water and will leak through pin holes which would contain water. If this is done in glass, it will have to be fabricated by really careful fiberglass workers, and they will need space in which to work easily, so the corners and edges can be properly dealt with.

Have you thought about a bladder tank or tanks? This might be a safer bet.

Re: the genset, we had very poor experience with Balmar and could not recommend them or any of their products. We ended up throwing out the genset which they supplied to us and replacing it with one of our own design. In our case, we are using a four-cylinder Yanmar (too big for you) with a Village Marine 50 GPH watermaker mounted on top and two Electrodyne alternators. We use a manual throttle to adjust rpm. Very simple and we adjust every 15 minutes during the first half hour.

We are using the same batteries as you have, Trojans. These should last 10 to 15 years IF they are periodically equalized. If the capacity is down, try cycling them to about 80% empty, then equalizing three or four times. It is often better to take the batteries out and send them to a battery shop for this, at which time the specific gravity of the batteries can be adjusted (we did this Beowulf’s Trojans in September and after 4 years of service they were at 107% of capacity at the end of the process).–Steve

Posted by Steve Dashew  (November 30, 1999)

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