With our cruise completed, it's time to have a quick look at "the numbers".
The interesting part as far as I am concerned is that the trip being a return trip up then down river, all things being equal current effect will be averaged out over the whole cruise.
River and lake conditions never really changed from a current perspective, though we had a couple of very windy days with a sharp little chop that slowed us down for a while.
So the numbers are going to be fairly representative of Enfin's performance, not forgetting that the bottom paint is 3 years old yet appears to still be performing its job rather well.
For 37 days of cruise, we used exactly 200 gallons (US) of diesel. We had added 300 gallons as we left Portland for as near as makes no difference to US$1,000 so the diesel costs for the cruise were about US$670. That's about US$19 per day all inclusive for diesel.
Total distance cruised was 620 miles: Is that to say Enfin makes over 3 miles per gallon?
Yes but it gets better than that:
We stopped mainly in marinas with power and water when we could but about a third of the time we had neither and had to make our own power. We weren't shy on using the generator as we needed it, both to properly charge the batteries all the way, and to have a comfortable "house like" experience on the boat.
I can't easily distinguish diesel used for the engine from that used for the generator without spending way too much time logging things, so this means the main engine is more efficient that 3 miles per gallon.
Main Engine was used for 127.5 hours and the generator was used for 76.8 hours. The diesel heater furnace also kicked in certain days and cold nights, adding to the diesel consumption. As with the generator, I can't easily track its consumption independently.
Last, we idled the engine as we were transiting the locks, so total idle engine time tied to a lock going nowhere was 8 hours. So our actual miles per gallon is again a little higher if we could exclude those hours going nowhere.
With either the generator or the furnace, I could easily run tests by using the day tank's gauges to ascertain their exact consumption. In the grand scheme of things, with such a low consumption overall I don't see the point yet. I'll do it one day just to know my boat better, but as it is, the safety margin I include in my diesel calculations more than includes generator and heater uses.
I find it's an interesting confirmation that diesel costs are not a major factor in Enfin's operating costs when coastal cruising. Many have made that remark before on passage makers our size, but it's nice to see for ourselves. We spent more on marinas and restaurants than diesel for example. And of course, a lot more on all the other operational costs like routine maintenance, insurance, etc.
This cruise was a lot more navigation intensive than our normal cruises where we do not hesitate to spend days and even weeks in the same place if we like it, so it means a more normal, more relaxed cruising rhythm would yield and even better diesel use per cruising day. Spending a couple of nights per stop where we spent one night only would bring the fuel costs down to less than US$10 per cruising day. Quite an achievement I think.
All this confirms to me that we chose our boat wisely (I'm an Indiana Jones fan). Enfin's hull and engine are so efficient we can just sip diesel along and literally go to the end of the world on our huge 920 gallons fuel tanks. Or we can coastal cruise at our leisurely pace without worrying about fuel.
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