MPG

kjretlaw · Mar 18, 2013

With boating it's not really MPG but GPH (Gallons Per Hour) you should get about 1GPH average. 100 Statute miles = aprox 87 nautical miles. 87 / 6.6 = 13 gal fuel. or 15 gal if the 100 miles stated were NM already. I believe you should have a 30gal tank so you should be fine even factoring in winds and currents. The alternative would be to sail it home and save the fuel but an extra 5 gal contain of fuel on the deck may add a comfort factor as well.

Don S/V ILLusion · Mar 18, 2013

If the above doesn't answer yor question, how big is your fuel tank?

navigator97 · Mar 18, 2013

You should be fine with a 30 Gal. tank, but it wouldn't hurt to have a 5 Gal. Jerry jug along just in case. I have kept meticulous fuel consumption data on my 1990 H-33.5 with a 2GM20F engine (2 cylinder). I get about 0.3 GPH with a new mixing elbow and up to about 0.45 GPH when the mixing elbow get "coked up". With a 3GM (3 cylinder) engine, you can expect 50% more that that. Therefore you should get 0.45 GPH with a new mixing elbow and about 0.6 GPH when its "coked up". So rounding up to 1.0 GPH should be safe. You also probably don't want to go below about 1/3 full in the tank. when fuel sloshes around, you don't want to suck up any air in the fuel pick line. Diesels don't like air in the fuel injection, and they quit. You then have to bleed the fuel lines at the fuel filter (on the engine) or at the injectors. Just avoid that.

Don S/V ILLusion · Mar 18, 2013

smoothsailing said:
Thanks Don,

I did know it was GPH.........spending to much time in my car.

Thanks for the formula, the distance is in NM and it is a 30 Gal tank.

Regards

Bill

Assuming a full tank, 30 gal is essentially 30 hours. You have sufficient fuel for a round trip at 5 knots (almost)

Steve Dion · Mar 18, 2013

Regardless of what others may tell you, I would always figure at least 1 gal/hr of operating time. This may be a little high, but better safe than sorry.

Just like Don said!

Rocket1 · Mar 18, 2013

When we bought our 340, it was 127nm to bring it home. There was ZERO wind the weekend we brought it home, so we had to motor the entire distance. We started with a full tank (30 gallons), and filled the tank when we arrived home. It took exactly 17 gallons to fill the tank. You should have absolutely no problems traveling the 100nm home with the fuel on board, unless there is something seriously wrong with the engine.

steve stark · Mar 18, 2013

Bill, I have also kept good records on our H340. We have averaged anywhere from 0.45 to 0.60 GPH depending on seas, headwinds, etc. We run at 2800 RPM at 6.5-6.7 knots.

Rick · Mar 19, 2013

Your going to love the boat. The 340 of that vintage is among the best bang for the buck in modern sailboats. Lots of room, power, and sailing potential.

All good advice from above. .65 is conservative. I actually cant make my boat burn 1.0 per hour even at full throttle so I wouldnt make a fuel stop by that theory.

Two things too keep in mind. A fuel guage upgrade can be made at WEMA for under 200 dollars (guage and sending unit) and is one afternoon of work over the crap stock fuel guage. Tachs arent always totally accurate. The other, dont think speed through the water for your fuel calculations. Its actually VMG or SOG because if you have a three knot current against and you are doing 6 knots on the paddle wheel thats 3 knots VMG so that marina that is 12 miles away is actually gonna cost ya 2 to 3 gallons and not the 1 and change you figured. Also as above mentioned, your stock 30 gallon tank is actually about 27 gallons usuable at most.

You will enjoy the boat!

Benny17441 · Mar 21, 2013

Pardon my intrusion, but a 30 gallon tank may only yield 27 gallons of usable fuel depending on the weather conditions and if you prudently reserve 2 to 5 gallons in case of emergency you may see that tank shrink to 20-22 gallons for planning purposes. Don't know your route or your opportunities to refuel along the way but if you need to make the trip in one leg I would strongly urge you to carry the extra 5 gallons in a can on deck. You may get lucky and be able to motorsail downwind at 7 knots an burn under 13 gallons for the whole trip but you will not know that, until you meet the conditions underway. The secret is knowing at all points wether you will have enough fuel to complete the trip. At the first indication that you have that you may not make it is the time to make a change in destination or shut down the engine and rely on wind propulsion alone. I realize I'm advocating being overcautios but knowing the limits and the alternatives is what allows us to smartly push the envelope or calmly conclude a trip with far less fuel than normally anticipated. It is not fun having a 4 hour projected navigation turn into a 6-8 hour ordeal but it happens.

TLW · Mar 21, 2013

Smoothsailing, Just noticed the Raritan Yacht Club signature. If you know Gary & Ann Myer, say hello from Tom Wehr.

Stu Jackson · Mar 22, 2013

Sorry to hear about your friends' boats.

Good advice here. This is a simply PERFECT time to begin to record your boat's fuel use. Make sure you record the engine hours when you start, and start with a full tank. Whenever you refuel, note the engine hours and gallons. Within a few fill ups, YOU will know for sure what YOUR boat uses.

http://c34.org/bbs/index.php/topic,3841.0.html

Have a great trip and congratulations on the boat.