Diesel capacity/range

[BillKny]

Originally Posted by Reefmagnet

I reckon for distance cruising, you need about a 500 nm range at a minimum

Of course whatever profound pronouncement you make about how a "serious" cruising boat needs to have a fuel range of "at least X" there will be somebody who has done a circumnavigation (or two) with less much less than X.

We have a single tank of 600 liters with gives us a range of about 700 NM. We do about 15,000 miles a year, and typically fill up two or three times.

When on passage we are perfectly happy to furl sails and wait for wind. Our passage weather windows are as much about looking for wind as they are about avoiding bad weather. If we were in a rush, we wouldn't have bought a sailboat!

We do have about 80 liters of storage in jerry cans, but we only ever fill those for economic reasons, i.e., fuel is REALLY cheap where we are, and expensive where we are going. Never have we needed that fuel to complete a passage.

[Tomodore]

On our 34 sloop we have a 55 gal capacity plus 20 gallons on deck in jugs. On a simple long passage say from San Diego to Cabo not much diesel required since wind is fair. (Unless you need to rush to catch all the haha parties) For less reliable passage say from Chiapas Mexico to Ecuador we buy several extra “panga jugs” for more fuel for just one passage. And then give the jugs away when we arrive.We use a block over our fuel fill with a shaker hose siphon system for fuel transfer. Very important to test your fuel transfer under way on a shakedown. Of course if there is strong wind you don’t need to motor. Not having large tankage can be solved, perhaps with less trouble than folks with multiple large tanks trying to keep the fuel fresh since most boats only occasionally make long motoring passages. Just my highly opinionated view. P.S. We used most of our fuel from Mexico to Ecuador but under 5 gallons on the return.

[Fore and Aft]

I surveyed a yacht for a Captain Ron type character. He had a lot of escapades from running out of fuel at the worst possible time. His fuel tank was very small and needed topping up regularly which was fine unless he forgot..........
Cheers

[mvweebles]

As a past delivery skipper, I can say that every owner I encountered was wildly optimistic in their fuel consumption projections.

Sailboats routinely have lousy prop efficiency when powering.

The Post immediately preceding this has the ring of truth.

[Lost Horizons]

As far as I am concerned, the full tank should last about a year with a typical use. For many people typical use is about 100 hours a year. For a boat on average burning 0.5 gallons per hour that translates to a 50 gallon tank. (My tank is 55 gallons.)

[Compass790]

This will make you laugh,
20 litre tank, 20 litre container lashed on deck. Fuel consumption 600cc per hour at 4.5knt in 10 knts or less breeze. 300 mile range. Yanmar running at 5hp.
Might get another jerrycan if we were going from NZ to Tonga but plenty for coastal cruising.

[Adelie]

Originally Posted by davil

what capacity (gallons) is your tankage for more than day sailing? My 30 ft Cape Dory has a 20 gallons diesel capacity, which is fine for day/weekend. On longer passages is not. Curious about what other sailors consider their minimum? to deal with calms, etc. The question takes into consideration the usual, is a sailboat, you use your sails, etc.

Your question is better phrased as what range do I want at what speed?

Your most economical speed will be about 3kt and you should get in the range of 18-20nm/gal.
At 5kt I would guess about 10nm/gal.
Going slow has a really big effect on fuel economy.

The minimum speed you are willing to motor at plays a part here.

Me, I’d be happy with 400nm at 4kt. My guess is that would be about 25-30gal for the Cal-34 I’d like.

400nm should get you across most parts of the doldrums unless you get unlucky and hit a wide spot.

Since I intend to get an electric outboard and carry extra panels sufficient to push me at 3kt during the day 20-25gal would actually provide considerably more range but at some cost in time. For the no-cost range I would be willing to take the speed hit. It’s all about your attitude towards boat speed.

[hpeer]

Concerning safety of fuel on deck, I was carrying some spare jugs. This year doing some mods it was expedient to replace my crappy old day tank with a new custom tank. More fuel and better space utilization. Went from 12 gallons to 42.

We will now carry a single 5 gallon jug on deck (just because) and that will clean up the deck a lot, improve access.

We also modified our water tanks so they are now truly separate. So we can get rid of the water jug.

We still have too much on deck. 2 dink jugs, 1 diesel jug, 1 gas jug (for Honda), 1 kero jug.

[Jackg]

A big question is how much of the fuel in your tank can you use. On our 32' ketch we had a rectangular 40 gallon tank about 8 inches deep. In even moderately rolly seas we couldn't get more than 25-30 gallons before sucking air.


I built a replacement 63 gallon tank from fiberglass. The bottom tapers down in two directions to a hemispherical sump. On a 15 degree heel we can get all but the last quart. A pickup lower than the engine pickup goes to a small pump to pump out crud, though we never get any.


At 5 knots in a flat calm we consume 1/3 gal/hr giving us almost 1000 nm range. On one trip we motored almost the entire way to Bermuda so were happy to have that.

[AJ_n_Audrey]

My Westerbeke 40 burns .75 gal per hour, and I have a 50 gallon tank. I usually carry an additional 25 gallons in 5 gallon jugs. I would never run down to less than 5 gallons in the tank, but assuming I used 70 of the 75 gallons and averaged 5.5 knots, I could travel 511 NM. Or much further traveling north in the Gulf Stream. 5.5 kts is conservative.

[Copacabana]

My 35 foot Vindo 50 has a 290 litre diesel tank. Motor is a Yanmar 3GM30F that burns just under 2 litres an hour at 6 to 6.5 knots. That's 145 hours of motoring (6 straight days) and a minimum range of 870 nautical miles. I could stretch the range to 1,000 NM at a lower RPM.

[davil]

Originally Posted by AJ_n_Audrey

My Westerbeke 40 burns .75 gal per hour, and I have a 50 gallon tank. I usually carry an additional 25 gallons in 5 gallon jugs. I would never run down to less than 5 gallons in the tank, but assuming I used 70 of the 75 gallons and averaged 5.5 knots, I could travel 511 NM. Or much further traveling north in the Gulf Stream. 5.5 kts is conservative.

=====================================
thank you Audrey
have the same Westerbeke 40 on my Cape Dory 30 and average about the same (.75 g/h)
As mentioned have a very small tank (20 gl) and been carrying 6 jugs =30 extra gallons.
last time cruising(2019 before the plague) realize cannot longer refuel and move jugs while under way,physical limitations!!!.
Just purchased a 25 gallons diesel bladder will go on deck behind the mast,will gain safety of not going overboard,cleaner side deck to walk and do away with electric transfer pump as the bladder transfers by gravity.

Negatives all known,heavy extra weight on top and needs to be extra secure to keep it on board!!! on rolling/heavy seas.
If I was only 40 years younger will not be doing this and if future use will be longer more likely will add permanent tankage,not the case.

But compromises are always the price we deal with.
This gives me about 300 miles range? not ideal but that is what I got.
Added 2 solar panels to keep my start/windlass batteries bank and some extra into the house banks for essentials (electronics)