Trying to figure fuel range---

[Emerald-coast-Grady]

I'm trying get an idea of the range of the boat. I have taken it out some already this year but haven't really been paying attention to the fuel numbers (Just the pump price number!). I plan on making a run in a week or so to the edge (~30miles one way) to Bottom fish and troll. I have searched the net for some other folks findings but i haven't seen another 22' Seafarer with twin engines they all have singles. Do you guys have any estimates on what i can expect. Running a 87' Seafarer with 1997 Mercury 135hp offshore also have the aux. fuel tank
Thanks

 

[Tuna Man]

This is just a wild guess based on my previous boat (92 24' Explorer with 250 EFI). Typically got around 2mpg at cruise with average load. With your boat being a little shorter and lighter but set up with twins - I assume you will do about the same at cruise (maybe running a little faster). If I recall my fuel burn numbers were something like:
Slow troll (3.0mph) 2gph
Medium troll (6.0 mph) 3gph
Fast troll (9.0 mph) 8gph
Cruise (28 mph) 14 gph

Lightly loaded in flat water add about 10% to the speed at the same burn rate.

Heavily loaded in rough water add about 15% to the consumption rate at the same speed

I think you will get about the same as above with twin carbed motors on your boat. If you run at over about 4500 I suspect you will not get over 1.75 mpg.

 

[Bob's Cay]

Some rules of thumb that I was told some years ago concerning Carbed engines. At WOT you will burn about 10% of HP per hour in fuel so in your case about 27 gph. At cruise you should burn about 75% of that or about 20 gph. Take the capacity in gallons of the tank and divide by your consumption (assuming 20 gph) to get your run time. Multiply that times your cruise speed to get a rough idea of range.

In round numbers for example, if you have a 140 gallon tank you can run for about 7 hours at say a cruise speed of say 30 mph you would have a range of 210 miles.

That's how I would calculate range. Remember the rule of 1/3. 1/3 out, 1/3 back, and 1/3 in reserve. Better safe than sorry.

Once you have an estimated range you can fill up, run a typical day, and refill when you return. Compare that to the number of hours run to get a number that approximates your consumption including trolling, drifting, no wake zones, sea conditions, etc.

 

[Emerald-coast-Grady]

Some rules of thumb that I was told some years ago concerning Carbed engines. At WOT you will burn about 10% of HP per hour in fuel so in your case about 27 gph. At cruise you should burn about 75% of that or about 20 gph. Take the capacity in gallons of the tank and divide by your consumption (assuming 20 gph) to get your run time. Multiply that times your cruise speed to get a rough idea of range.

In round numbers for example, if you have a 140 gallon tank you can run for about 7 hours at say a cruise speed of say 30 mph you would have a range of 210 miles.

That's how I would calculate range. Remember the rule of 1/3. 1/3 out, 1/3 back, and 1/3 in reserve. Better safe than sorry.

Once you have an estimated range you can fill up, run a typical day, and refill when you return. Compare that to the number of hours run to get a number that approximates your consumption including trolling, drifting, no wake zones, sea conditions, etc.

Thanks guys!!
So looks like with my cruise speed witch is about 31mph and with the 93 and 55 gallon tanks full at the estimated burn rate of 20gph....

148gal./20gph=7.4hrs run time

7.4hrs run time x 31mph=229.4 mi range

147gals of fuel x 3.89gal (todays land price here) =$571.83 + 3gal oil @20.oo =$631.83 :shock: The memories=priceless!!

With the 1/3 rule in place that equals 152.6mi travel with 1/3 in reserve
Should be plenty for a 60mile trip with trolling in between. I'll check and figure out the true numbers after the trip is done...Man i need a flow meter..

 

[nitrox32]

I use an easier method to figure range. I just take my miles/gallon X fuel tank capacity = range.

For instance the other day I went out and put 44 miles on the boat, then I topped it off with 18 gallons of gas = 2.44 miles per gallon 44/18=2.44

Fuel capacity = 150 gal x 2.44 miles/gal = 366 miles (range)

 

[Emerald-coast-Grady]

I use an easier method to figure range. I just take my miles/gallon X fuel tank capacity = range.

For instance the other day I went out and put 44 miles on the boat, then I topped it off with 18 gallons of gas = 2.44 miles per gallon 44/18=2.44

Fuel capacity = 150 gal x 2.44 miles/gal = 366 miles (range)

Im gonna make sure i get it figured out when im down in a couple of weeks for the whole week. We are gonna run out to the edge see if we can troll up a wahoo or two while we are there..

Nitrox32 where do you keep you Grady at? I hardley ever see any of them in our neck of the woods. My house is in Santa Rosa Beach. We put in at Joes bayou..

 

[nitrox32]

I keep my boat on a trailer next to my house in Shalimar, we launch out of Ben's Lake on Eglin AFB. We use the boat strickly for scuba diving and we usually stay within about 14 miles of the Destin Pass.