Planning fuel for a longer trip

[infy]

I bought a boat on Saturday (1990 Avanti 2955) and I'm having a mechanic give it a check tomorrow. If we're in good shape I need to eventually move it to new moorage.

It will be between 80 and 100 miles by water on the puget sound. It will just be a slow cruise and I expect it to take all day. Just 8 - 10 mph max and no more.

I could get it towed but it seems easier and less complicated to just cruise. And I'm looking forward to that. I've got a friend coming and it should be a good time.

The question is, how much gas should I plan to use? Will I need to refule? How often?

I see a lot of GPH stuff out there.. and I don't get how that's significant to anything. Should I assume about 2 mpg at an easy pace?

 

[alldodge]

First running slow will not necessarily mean burning less fuel. What motor(s) does it have? Boat shows it has a 120 gallon fuel tank.

Where are you going from and to?

 

[infy]

It has twin 305 mercruisers 230hp each. I was thinking of just running one at a time.

Going from south of Gig Harbor to Everett.

 

[R055]

You will get better mpg or gph by being at planing speed. The boat is just plowing through the water at slow speeds. Good luck with the trip.

 

[alldodge]

What I'm seeing is it will be 45 miles via the Colvos Passage.
http://nwcruising.net/nm_folders/gig_harbor.html

http://nwcruising.net/routes9/route.0799.html

So moving with both engines on plane at 25 MPH, you should make it there in a couple hours and burn around 60 gallons. How did you come up with 80 to 100 miles?

 

[infy]

Well it's not direcrly from Gig Harbor but south by longbranch, wa.

I was also thinking I should hug closer to the marinas by Tacoma and Des Moines just in case we had any trouble. It's a long way and that seemed like a safer route.

I kind of eyeballed that figure. I may have been a little off

 

[Mischief Managed]

Instead of hugging shore, buy unlimited towing insurance and make sure the radio is working (good advice for anyone on any pleasure boat all the time). Run it cleanly on-plane (I'd guess 28 MPH or more) and you should get around 1.5 MPG which will give you much more range than you need. I routinely do 100 to 150 mile coastal cruises without refueling but I have a very accurate fuel flow meter and know exactly how much fuel I'm using and how much is left. My boat has a 192 mile range on-plane.

At idle it might get 2 MPG, idle to <10 MPH might yield 1.5 MPG, if you are lucky. If you run it at 10-15 MPH, it will get well under 1 MPG.

 

[Chris1956]

Gee, can you make some shorter runs and get used to the boat, and also make sure she is reliable? With a 120G tank, you should make 80 miles, however, wind, current waves and other items can double your fuel burn.

If it were me, in an older boat, I would make sure she is reliable, get the best estimate of the distance, make some measures of fuel usage per hour, fill the boat and take an extra 24+gal of fuel, and know where you can fuel up along the way.

Also you must be confident in your navigation. I would plan for some waypoints visual and GPS, along the way, so you cannot get too lost.

JMO.

 

[KnotConnected]

Worth mentioning: It's a wise idea to always keep some fuel in your tanks for reserve, never plan on pushing your absolute fuel limits. If you think you'll be using 75% of your tank or more, I would plan on a refuel before you get to that point. At the very least, know where you can stop to gas up and pay attention to where your tank(s) are when you're coming up to the next fuel dock.

Because its a new boat, I'd also probably keep a handheld VHF on me for a backup as well.

"Nothing more useless than the fuel you left at the dock."

Just my $0.02

 

[Chris1956]

Yes, you will want to use no more than 2/3 of your fuel to get to your destination.

 

[Scott Danforth]

get towing insurance.

 

[gm280]

WOW bold venture on a new-to-you-boat with only a mechanic verifying it is water worthy. I certainly fill up tight and even carry a couple five gallon spares even with a planned stop at a marina. You have zero experience yet with that boat and therefore have no idea what either of the engines are capable of doing or their fuel usage. A ton of great info provide in the previous comments. Please be safe and very careful. JMHO!

 

[infy]

Yeah, I plan to run it for a couple hours before taking it out on the trip. Radios, life jackets, etc are a given.

 

[JoLin]

I think you're preparing pretty well for your trip. It's ambitious and a little gutsy, but not crazy. I bought Escapade III in the Bronx and had to get it home to Babylon on L.I. Driving it home was the most practical option. I don't recall the precise distance, but it was 60-70 miles and a 7 hour ride down the East River, through New York Harbor, out into the ocean, in through the Jones Inlet, then along the state channel to home.

1. Unlimited towing insurance with Towboat US or Seatow.
2. Pick out a couple of full service marinas along the route where you can pull in if you have issues or need fuel. Plan on refueling by the 2/3 point and DO IT even if you think you can make it the rest of the way without. You don't know what might be sitting in the bottom of your tank, so don't run it down too far on this trip.
3. New fuel-water separators on the engines and a bunch of spares. Any issues with the fuel will negate the safety advantage of dual engines, 'cause it'll knock them both out.
4. Good weather and leave early. Give yourself as many daylight hours as possible.
5. Write out your travel plan and route (float plan) and have someone on shore keeping track of you. Check in periodically and let that person know where you are and how you're doing.

Best of luck!

My .02