Taking long passages with gas engine

[edwardc]

Our nine month trip down the ICW, over to the Bahamas, and back up the ICW was about 500 engine hours and ten oil & filter changes.

[Mo]

I find the atomic four sips fuel in calm waters. This past weekend we did 54.7 nautical mile trip and had to motor 45.5 nautical miles of it. The first 24 nautical miles were in no to light wind conditions, some ocean swell, but relatively calm. Throttle just above idle for that portion of the trip. The other 21.5 nautical miles I ran the engine had it on the nose around 18 kts. Kept speed around 4 kts for all of it, and here's the kicker. I filled the boat up today and it took 5.5 gallons...that was it. Took 10 gallons down and figured she take most of it...not so. Pleasantly surprised. I have no idea what the rpm was but I set the throttle just under half way, not screaming, she had more but there was no need to be doing any more than 4 kts in that.

[nyvoyager]

Great thread - thanks

I've been considering a NY to Maine cruise for some time now. Maybe next summer after replacing the engine and mast. I'll post my question about this new to me engine in a different thread.
I usually estimate fuel consumption conservatively and for the ease of calculation use 1 gallon per hour. I know it is far less than this and sometimes by as much as half. Also with a 20 gallon tank that sets my conservation range at 100 miles motoring (5kt speed) - short by 50 or so miles of getting me across the Gulf of Maine if I were motoring the entire way, which I don't expect but would be prepared for.
As others have mention, I added a 50 watt solar panel a few years ago and it greatly relieved running the A4 from the responsibility of charging batteries.
But this is evolving. I find that on long sails, through the night, I run short on power with nav lights, radar and chartplotter running.
Since replacing the engine, I have installed a 65amp alternator which helps a great deal. I have also rebuilt the battery box and house bank to include 240ah of battery.........the never ending spiral - I also added a portable refrig/freezer unit and that brings me to adding more solar.
Led nav and mast lights waiting to be installed
The point is on a long passage, night ailing will take a lot of battery power and you need a way to recharge. Go solar to save fuel and engine time.
Thanks for a great thread guys

[ndutton]

Have you considered your battery capacity the same as your fuel storage? It's really the same thing with the batteries as the tank, the electricity as the fuel. Points to ponder (having no idea of your battery arrangement):

• Think of your battery storage capacity in terms of range without replenishment (night time).
• One huge exception to the fuel tank analogy is for the health of the batteries you shouldn't consume more than half their capacity at most.
• Why have a big alternator without the capacity to store sufficient charge?
• Same thing with solar if you can't store sufficient charge.

[nyvoyager]

Neil,
Thanks - Yes I understand the relationships.
It has been a slow evolutionary process.
I have the battery capacity and the recharging ability via alternator.
I fall short on the solar if cruising.
That will hopefully be corrected over the winter

[ndutton]

Not trying to argue but this

I find that on long sails through the night, I run short on power with nav lights, radar and chartplotter running.

suggests maybe you don't have the necessary battery capacity. Just going by your report.

[nyvoyager]

Oh sorry - the batteries where only altered and added to this year.
To my previous escapades - yes you are correct.
I believe I am fine now.
will find out in the next few weeks

[nyvoyager]

My point was really meant for the OP who intends to go on a passage.
The warning being, night sailing uses power and he should be aware of this.
Nothing more really.