Trojan Boat Forum

Went to add fuel to my tank and fuel over flowed..

Tank isn’t full
Vent isn’t plugged

Any suggestions?

Over flowed from the fill or vent ?

Both.. first fill then vent and thanks for the reply

Took the vent tube off nothing in it.

May want to check the vent, you should actually see fumes exhausting from the vent during fueling. If not check that first, secondly check your main fuel hose from fill point to tank, if you lift your starboard rear hatch, you can see it pretty good, if one of the supports that hold it up, failed, your hose could have a pinch restricting the flow.

Knowing where it came out will help diagnose. Quite oncommon the fuel supply is greater in volume than the vent can displace, however if you fill for 15-30 seconds and stop the pump and listen, you should not hear any gurgling or burping, if you do you have a vent restriction.

One other thought.... with 10+% ethenol at some pumps, possibly your fill hose or vent was affected and internally failed causing a restriction? We use only non ethenol fuel exclusively.

Jimmy wrote: ↑Wed Aug 01, 2018 10:22 pm May want to check the vent, you should actually see fumes exhausting from the vent during fueling. If not check that first, secondly check your main fuel hose from fill point to tank, if you lift your starboard rear hatch, you can see it pretty good, if one of the supports that hold it up, failed, your hose could have a pinch restricting the flow.

Knowing where it came out will help diagnose. Quite oncommon the fuel supply is greater in volume than the vent can displace, however if you fill for 15-30 seconds and stop the pump and listen, you should not hear any gurgling or burping, if you do you have a vent restriction.

One other thought.... with 10+% ethenol at some pumps, possibly your fill hose or vent was affected and internally failed causing a restriction? We use only non ethenol fuel exclusively.

All the above plus are you sure its not full ? Some pumps may fill too fast so that could be a issue . Are you diesel ? diesel can foam badly when filled fast .

Fixed thanks for all the help. After checking vent line again found a little blockage in the line. Thought it had enough flow when blowing into it but after removing it and snaking it out found a mud like nest you all talked about.
My vent line is 1/2 copper not rubber with three 90* fittings. Real fun getting in an out. Plus I don’t ever remember removing the screw in vent cap...love kids but don’t know if it just some how vibrated loose or if the little ones did it at anchor. Either way it’s fixed and made a great trip from South Haven Mi to Chicago with a night in Michigan City Indiana. Then back to South Haven Mi. Love cruising in the week days.
Before u even ask I will just give the numbers
Total miles 200
Fuel 287 gallons
Price for ethanol free in south haven 4.25
Michigan City Indiana 3.75
Giving me a 1.4 per mile burn rate at 12 mph
At 2400rpm
Didn’t think it was to bad
HRs of travel 16 hrs

•first time in locks ever
•first time in River and fit under all bridges with antennas down had only a foot clearance (nail bitter)
•first time doing a crossing of Lake Michigan

Glad to hear. You should have a screen cover on your vent hose to keep mud making bugs out. If not, you can make one out of aluminum screen that is cut to just sligtly bigger than the vent, make it into a cup shape and push in with pencil eraser side. It will stay put and keep out the critters

Good report on the trip and fuel. I found I can get just under 1 gallon per mile cruising around 8-10 mph and at 1,000 1200 ish RPMs. And if you are in a hurry, better take out a small loan.... they are thirsty buggers, I enjoy the leisure cruise tho and a great ride. Did Grand Haven Mi to Mackinaw, could have just about made it on one tank going up with the leisure cruise. (Total 330 miles) On the way back, ran 18-22 mph @ 3000-3200 rpms, burned just over 700 gallons..... ouch.

TodaysTheDay wrote: ↑Mon Aug 13, 2018 8:20 am Total miles 200
Fuel 287 gallons
Price for ethanol free in south haven 4.25
Michigan City Indiana 3.75
Giving me a 1.4 per mile burn rate at 12 mph
At 2400rpm
Didn’t think it was to bad
HRs of travel 16 hrs

FWIW You would have burned about the same at higher speed (on plane) or a lots less at hull speed (about 8 knots ) or less At 12 mph your plowing water .

not to hijack the thread, but...

heres the deal - the speed between hull speed and planning speed = plowing water speed = inefficient speed.

It's hard on your drivetrain and your fuel burn will waste fuel

FOR PLANING BOATS:

Formula:

H = 1.34 × √(L)
M = H × 1.1508
N = H × 1.852

Where,
H = Hull Speed in Knots
M = Hull Speed in Miles/Hr
N = Hull Speed in Kilometers/Hr
L = Boat's Waterline Length
Hull Speed: It is otherwise called as displacement speed is the speed at which the wavelength of the bow wave (wave formed at the bow of the ship or boat, when it travels in water) is equal to the length of the boat. As the speed of boat increases from rest state, the bow wave's wavelength increases, and usually its crest-to-trough dimension (height) increases as well.

Boat Displacement Speed Calculation: Make use of this simple online hull speed calculator to calculate the boat displacement hull speed with ease. Also, you can refer the below-given example problem to understand the displacement hull speed calculation on your own.
Example

Hull Speed
Calculate the hull speed, if the boat's waterline length is 12 feet.

h = 1.34 * √(12)
= 1.34 * 3.46
h = 4.64

Hence the hull speed is 4.64 knots.

RWS

Spot on RWS. My calculated hull speed is just under 8 MPH. I used 34 feet waterline. That is my leisure speed most of the time. However, the first mate gets hungry, and the crew threatens mutiny if we dont reach port in a timely manner, so, sometimes we step it up. But only slightly. At cruise speed I get around a mile per gallon or so depending upon sea conditions. Normal?

454's

@ RWS thanks for the great info.