Fuel tank

baldy1

Cadet
Joined
Sep 19, 2010
Messages
7
Hello everyone and I apologize if I'm in the wrong forum. This is new to me. I have a question about relocating my fuel tank. I have a 1966 17' Glasspar. I believe it weighs about 1,9800 lbs. I had a 1965 1oo horse Mercery on it, and it is long gone. I think it weighed around 350 lbs. I also think it was the orginal set-up. Anyway, it has two 10 gallon built in tanks that extend into the deck area that have jumper seats on top of them. Get the picture? I would like to remove them and install a bow tank. I have already purchased one (used) it is either 20 or 24 gallons. I realze I don't need to fill it up, but that kind of defeats the purpose too. When full I think it would weigh 200lbs. My question is: would it be safe? Logical? I don't want to swamp the boat if a wave came over the bow. I still need to get a motor also, so that kind of comes into play. Any help or info on where I can go to find some answers would be appreciated. Sorry this is so long, but wanted to get all the information included.

Thank you
 

ezmobee

Supreme Mariner
Joined
Mar 26, 2007
Messages
23,767
Re: Fuel tank

I can't think of any reason why you couldn't add the bow tank. Assuming it's a closed bow boat, they often could stand to have some weight moved forward anyway.
 

baldy1

Cadet
Joined
Sep 19, 2010
Messages
7
Re: Fuel tank

Thanks for your reply. A few other people I asked said pretty much the same thing about the weight up front. I'm just a little cautious about modifications, due to the fact last summer a boat was swamped and sunk, one life lost. A whole different boat then mine. Mine is a closed bow, this was an open one with a full load, 10 people I believe out for a sunset cruise. They added a wake board or ski tower. A wake from a passing boat flooded the boat and I heard it went down rather quickly. Kind of a freakish accident.
Thanks again for the reply and I'll move ahead with the project. Would motor size be a factor? I plan sticking with one about the same weight as the one I removed. Around 350 lbs.
 

wishboneZ51

Petty Officer 2nd Class
Joined
Jul 11, 2010
Messages
135
Re: Fuel tank

The motor that you are looking for, will it have trim and tilt? I am in the same process with my Glasspar which is going to carrie a 110 Evinrude V4. I am considering the same in gas tank up in the bow. What is wrong with the set up you have now? Why are getting rid of the two tanks you already own? How did your boat ride with the previous motor on it? Please post pictures of your boat...
 

baldy1

Cadet
Joined
Sep 19, 2010
Messages
7
Re: Fuel tank

Yes, I am going to make sure the motor has a tilt and trim. My old motor was a 1965 100 horse with manual lift. The main reason I would like to put in a bow tank would be for more room. The two tanks in the rear extend into the deck area and have jumper type seats on them, they never get used. The boat I felt handles well the way it is, but does tend to get blown around a bit in a wind and or strong current while trolling or at slow speed. I'll try and attach a photo. If it does not work, I could e-mail one to you.
Thank you
 

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Woodonglass

Supreme Mariner
Joined
Dec 29, 2009
Messages
25,929
Re: Fuel tank

Hey baldy,

As you can see from my thread, my boat is similar to yours and my plan is to use this tank

9398728.jpg


under the bow. These boats will handle MUCH better with a bow tank, IMHO. The weight distibution will be much more desirable. A 350 lb long shaft motor on your boat will not adversely affect your new configuration. In fact it will probably level out your boat an decrease the probability of swamping. Your transom will ride higher in the water and not allow back wash as readily as before.

I'm just sayin...:D
 

erikgreen

Captain
Joined
Jan 8, 2007
Messages
3,105
Re: Fuel tank

A 24 gallon gas tank, full, will weigh about 150 lbs, depending on temperature and gas blend....
 

Yacht Dr.

Vice Admiral
Joined
Feb 26, 2005
Messages
5,581
Re: Fuel tank

Are you sure you cant fix that 100 pony merc ? that thing just makes me grin ear to ear :) sweeeet ..

Nice boat man..

YD.
 

wishboneZ51

Petty Officer 2nd Class
Joined
Jul 11, 2010
Messages
135
Re: Fuel tank

Ok so where does the gas fill go and the vent tube? What about getting the fuel to the back of the boat into the motor? Do we need to add an electrical fuel pump and other required misc. equipment to make it run at the correct PSI to the motor?
 

wishboneZ51

Petty Officer 2nd Class
Joined
Jul 11, 2010
Messages
135
Re: Fuel tank

yeah but where do you put it where it wont take away from the bow of the boat YUK. If I have to install up front I will definately build a hatch that has the filler cap below the top cap so the lines are still there. Maybe with some blind hinges and one of those magnet type latches that you push to unlatch so you dont have any notches, cut outs or anything sticking out, what do you all think?
 

Woodonglass

Supreme Mariner
Joined
Dec 29, 2009
Messages
25,929
Re: Fuel tank

Yah, you could do that.
Here's one for less than $50 bucks

image.php


I'm just sayin...:D
 

SC's Forever!

Seaman Apprentice
Joined
Sep 26, 2010
Messages
42
Re: Fuel tank

Dear WBZ51/WoG.....Re: the location of the vent, filler, and feed tubes on the tank pictured..............I'm not familiar with the maker of this tank, but I don't agree at all with the location of the 3 tubes!!!!! The smaller end naturally goes toward the front, this puts all the tubes at the rear and usually a boat will sit slightly bow up both on the trailer and in the water. The fuel draw tube is fine..it should be at or near the lowest part of the tank. The fuel filler "could" work anywhere on the top of the tank. The problem is with the VENT location!!....The vent line MUST be located at the HIGHEST point of the tank when its installed in the boat.
IF the tank is piped up as shown, and is sitting slightly bow up, you can fill the tank with fuel as much as possible and still have an air pocket at the forward top portion of the tank because the vent line will be covered by fuel before the air pocket is filled.....The problem???? Depending on the temperature of the fuel and the temperature of air in the bow of the boat, its entirely possible for the air pocket t expand enough to force fuel back up the vent and filler lines!!! It takes relatively little pressure to accomplish this and you could have raw gas all over the place....Not what I'd like to experience!!!
If I understand you correctly, you are wanting to mount the fuel/vent assembly INSIDE the boat......Gas fumes are heavier than air and will collect inside the boat....I pray no one smokes!!!!......The combination fill/vent shown above is ment to be placed on TOP of the gunnels, so any fumes/raw gas spillage will fall OUTSIDE the boat.
You will not need an electric fuel pump....all that in necessary is to raise the fuel level to the highest point in the line, then gravity will take care of flowing it to the motor, where the motors fuel pump will supply all the fuel the motor needs. You will still need the priming bulb near the motor. If possible make the line from the tank back to the motor area from metal tubing, not rubber hose..at least 3/8" Inside Diameter..1/2" would be even better and make for an easier fuel flow.
Finally, yea, I know, I do tend to get long-winded!! Re: the estimated weigh of your Merc.....My 1979 140 HP Johnson V-4 w/Power Trim/Tilt weighs in just over 165 lbs. You could probably get a 200+ HP for that weight(Not that I would suggest it!!!)
Finally #2...Best of luck with your re-build..just remember..When in doubt?...Sing out!!! But above all....Keep it Safe and Enjoy!!!!!!
Jim in Hammond, La.
 

wishboneZ51

Petty Officer 2nd Class
Joined
Jul 11, 2010
Messages
135
Re: Fuel tank

Thank you for all your input SC'S!!

Let me explain in a little further detail what we are talking about. The filler cap whether it be made out of brass, crome, aluminum, or plastic. they all usually stick up above the top cap such as you were pointing out "above the gunnels".

We are discussing the ability to hide the filler inlet and vent not inside the boat but in a way that will not take away from the lines of the bow of the boat. It will just look out of place sitting there some place up front sticking up like a parascope on a sub.

Going with a system that inables you to enclose the fuel tank under the bow is no different then in a storage locker below or concealed in back or any other concealed place for that matter. Yes you do need to have two things, a vent inlet and outlet for the space, and the vent tube for the tank. These vent tubes can either be on the side of the boat which I see all the time or up on top such as the gunnels. My boat had vent tubes on the stern in front of the splashwell. If I were to install a bow mount fuel tank. I would make sure to create a ventilation system that flows with my boat and includes these vents ans well as the fuel vent line.

To solve any problems with over filling or a lack of filling due to the vent tube being submerged by gasoline because of listing and or bow position. You can have a bigger tank such as a 20 gal. and only fill up to let say 15-16 gal.

As for your hard gasoline line. That actually sounds like a much better plan then to run hose that can deteriorate and clog the fuel system much easier then steel. Plus the rubber line can rot rip or tear which would be very bad. So hard lines would be the way to go. As for a pump, I think some testing would have to be involved in order to dictate weather or not I am receiving enough fuel pressure going to the inlet of the motor. As we use our fuel from the tank, the amount of pressure giving head pressure will start to diminish. Without geting out my flow charts for water pressures I can safetly say that their is a difference in pressure. We also have to look at vibration and causing foam or air bubbles from the tank banging from any rough seas. This could develope air in the fuel system which can cause problems. I wonder if the bow mounted tanks have baffles in them like our water tanks do for large commercial riggs.
 

Yacht Dr.

Vice Admiral
Joined
Feb 26, 2005
Messages
5,581
Re: Fuel tank

Baldy ! you still here ? :)

I know..so much info It makes my head spin too..lol

I still think you should keep that 100 merc resto thing on there :)

Ok..heres the quest on what is being said here on the threads..

Lets say you put a 25 gallonish tank ( one tank ) suggested by another poster.. ook...fine...

Then SC said Basically " Dont Do This Mod Tank " ! .. Its flawed in a certain way..he is trying to explain it to you...

Then another poster said " ah..no worries " basically..

I would say..

I agree with SC.. DO NOT PUT this tank in the bow !

SC is trying to explain ( who cares where the fuel vent on deck..who cares where the fuel plate to put in gas is.. ) he/we are trying to tell you IF you look at the layout of the tank .. the vents/filler are on the BACK side of that fuel tank that was posted !

Meaning .. the front of the tank is Going to have AIR displacing the gas in the tank.. ( I personally would rather have the vent actually venting air out of the tank ). And he is right about filling your tank..then having fuel disperse out of your vent lines and or fill line.

See the thing about modding your Fuel tanks are Questionable.. for anyone Going to Mod there fuel should be checked out by a Pro..

There are too many reasons ( like you stated with the One life lost ) where Im Inclined to not tell you how to mod your tanks.

When It comes to fuel mods..just dont DIY.. I implore you...Dont..

Im not suggesting that You/Others do not have the Knowhow to do these mods..but I dont like the Idea that 1 does not...even 1 would ( under my guidence ) completely change my life forever..knowing that my help wasnt on par..

Dont mess with fuel..

YD.
 

SC's Forever!

Seaman Apprentice
Joined
Sep 26, 2010
Messages
42
Re: Fuel tank

Yacht Dr.....Basically you understand what I was saying.....Not meaning to say te tank CANNOT go in the bow, just that IT MUST be plumbed PROPERLY!!!!
Re: Boat sinking, loss of life.....The key word there is 10 passegers!!!! It was not loaded..IT was SEVERLY OVERLOADED!!!!! I don't know what the length of this boat was but it was much too small...Far too many novice boaters think that if they can seat 10 people, the boat can SAFELY carry that number....That ignorance is DEADLY!!!! I faintly remember a news article years ago about a vacationing family suffering such a disaster...The boat was a flat, jon boat, bateau TYPE!!!!
Now..for B-1......Any of my comments are refering to the FUEL vent....I am aware of the "area" vents you also refer to..more on that later. I am confused by your commints of having a fuel filler "that sticks up above the deck like a periscope on a submarine"??? Most normal fuel-fill deck plates are less than 1/4" above the deck!!! The spring loaded hatch plate in the reply above is similar in height.... "Almost all the boats I've seen have the vent fitting on the side near the rear of the boat"......???? Could it be that that is the BEST location to safely vent the fumes and keep them out of the boat???
Re: the deck mounted "clam-shell" vent scoops....These are mounted on each side of the rear deck, one facing forward, the other rearward. The theory is that forward movement of the boat forces air down the tube to the floor area "pressurizing" the area and forcing the fuel vapors(which are heavier than air an collect near the transom area on the floor" up the tube attached to the "scoop which faces rearward....Theory is that the air flow over the rear facing scoop creates a slight vaccuum which helps draw the fuel vapors up and out of the boat.....This hose MUST end at or very near the floor level.
I would not use the combination fuel fill/fuel vent assembly shown earlier and install it on the front deck....It would cause gas fumes to flow into the cockpit while underway.....
Your bow mounted tank can be made to work and work well as well as safely!!
You said you had already purchased a tank...I am assuming it is basically the same general shape.....Is it "plastic" or aluminum??? Where are the 3 nozzles located?? If its aluminium and all the nozzles are at the rear, any compatent aluminum welder can move it to the front and plug or remove the old to make it work perfectly! If its "plastic"..DO NOT attempt to install a NEW vent nozzle!! If you want to play with angles and math...you can raise the rear of the tank 1-1/2" to 2"+/- so it will be level or slightly lower in the front when the boat is being fueled and when running in the water.
Yea....I Know..Longwinded again!!!! But better safe than sorry, No?
I am very familiar with the "pressure loss THEORY due to friction" in a pipe or tube.
 

SC's Forever!

Seaman Apprentice
Joined
Sep 26, 2010
Messages
42
Re: Fuel tank

??????? Don't know what happened!!!! But to finish, B1 you are trying to compare apples to oranges here....The THEORY is that if you make a pipe long enought, you won't have any PRESSURE at the end because of pressure loss due to friction......True..BUT any liquid put in one end of the pipe WILL come out the other end!! We are basically talking about FLOW...GRAVITY FLOW!!! Your tank IS NOT PRESSURIZED, its only influenced by gravity. It will probably wind-up at aproximately the same elevation as the carbs on your engine....Head pressure from elevation differences probably are too small to be measured as is friction loss.....As stated in an earlier post, the fuel pump on your engine is perfectly sufficient!!!!
Put your fuel fill on the front deck, the vent assembly on the side near the transom, If you hide the fuel fill, just make sure any fuel spillage will drain into the tank, and pipe the fuel and vent lines with no "pockets" and you should be fine!!!!
ITS YOUR BOAT!!! Make it look like YOU prefer, Just do it SAFELY!!!
Good luck....I'm gone....Would still love to see some finished pics!!!
Happy and Safe Boating!!!!......Jim
 

wishboneZ51

Petty Officer 2nd Class
Joined
Jul 11, 2010
Messages
135
Re: Fuel tank

Holy Smokes how is it that I am being blazed for such a simple topic?:eek:

I may be new here on IBOATS and I do understand that a lot of info online is BS but there is a lot of good info on here as well....

I have to say I apologize upfront for displaying any anger or hatred towards anybody here on IBOATS but this is rediculous!

I was unaware that I needed to post my credentials nor the fact that I new what I was talking about. I dont post BS nor did I NOT UNDERSTAND WHAT Either SC or Yacht DR was trying to make points on.

NEITHER member had answered a single question on what either Baldy1 or myself had written.....

Now going back over each post there is WAY TO MANY quotes to prove this point. Both of you feel the same that putting a bow fuel tank upfront is not a good idea.

Are you serious, so all the tanks out there that are designed and built for the bow of the boat must be WRONG and the manufactures that have engineers and designers that implement, study, calculate, design, test, and retest have no clue what they are doing not to mention risking their lisenses to build and insurance on these products are all WRONG?

Do you see how silly you sound when you try to prove a point on a product that is already in production and sold to customers and in this point is a FUEL TANK which holds highly flamible liquid that is dangerous to life and property?

Now I am not questioning your credentials nor do I really care. But I do know mine and feel that I am being ridiculed and pushed as I have no idea what I am talking about and that is a personal attack on my credentials and voice on here that has to stop right now!

I am more then qualified to speak about liquids, fuels, vapors, hasordous materials, fires, or any other matter in this thread.

All of my Certifications and Lisenses in the Fire Department that I hold are Federal IFSAC Seals for ALL 50 States and I assure you as a Trainer Trainer in Hazerdous materials I know what I am talking about when it comes to fuels and vapors so please dont try to explain to me about displacing vapors in a space by means of ventilation.

Now back on topic with what Baldy 1 had started this topic about as well as myself and a couple others that are planning on installing a front mounted bow fuel tank.

A gallon of water weighs around 8.3 pounds. But a gallon of fuel comes in between 5.93-6.42 pounds per gallon. If we take a 25 gallon fuel cell and fill it with 20 gallons of fuel we can safetly say using 6lbs. per gallon of fuel would be sufficient for our discussion. Take 6lbs. per gallon X 20 Gallons in tank we have tipped 120 lbs. of fuel in our tank. That is 120 lbs of fuel putting pressure on the gasoline line feeding the motor. Depending upon the size of the fuel line and the length of it we will see a measurement of static pressure at the end of our fuel line so the calculation is definately going to be different for everybody.

To say 120 lbs. of any liquid is not creating a force of energy in which can change the characteristics of fuel inlets and returns is just false. Take a 6 gallon fuel tank and put it up in the bow of your boat 10 feet away from your motors inlet and tell me if you get good fuel readings I assure you "you wont". Every motor has different features, fuel pumps and were designed and calculated to be so many feet away from the fuel tank and without that info we are just shooting in the dark. That is why I posted the question if we need some sort of small fuel pump not to boost pressures to the fuel inlet, but to SUSTAIN fuel pressures CONSISTANTLY across the entire board wether the fuel cell is full or almost empty. You can always reduce the pressure from the fuel tank to the motor so that may be a solution as well.

Solving the issue of the fuel line was a great suggestion by SC and I thought I gave recognition for?:D

Now the picture Woody posted was just simply the picture of A front bow fuel tank. Not that all the features were specific to Baldy's or anybody elses needs.

The vent hose from the fuel tank is another valid point IF you did get the tank in the picture posted would cause for problems, YES that was not a question or problem that came up.

NOBODY ever made a comment on changing the design of any fuel tank nor did anybody post anything about building a fuel tank either. So I am trying to understand where that post came from?:confused:

As for the location of the fuel intake to the tank, vent line to keep the fuel tank pressure at its relative psi to size and quantity in the tank. That is what I posted as questions because there are bow mounted fuel tanks that are DESIGNED to go into the bow and I find it goofy to have the fuel inlet and vent tubes in the bow. So I was meerly asking if there was some sort of system, product that was used to solve these issues plain and simple. When all of a sudden I am being thrown under the rug for all this jargin and looked at like I am a fool.:mad:


There is a lot of info that I have learned from here on IBOATS and I am excited to learn more in all of the areas that I do not specialize in which is why I am here.

I hope that we can make this right and get back on track to what Baldy 1, Woodon Glass and myself were trying to resolve for our fuel situations.
 

Yacht Dr.

Vice Admiral
Joined
Feb 26, 2005
Messages
5,581
Re: Fuel tank

Hello Wishbone..and others..

There is no personal attacks on you..

Again... If you ( anyone ) wants to Mod there fuel tanks...they really should consult a pro.

Im not saying that you/others dont know what there talking about..its..just with fuel..

....

Hell..Ill tell anyone how to Full gel..or spray Imron..but modding fuel systems I have a hard time ( even over the phone ) to tell them how to m8...

Modding fuel...?

YD.
 

baldy1

Cadet
Joined
Sep 19, 2010
Messages
7
Re: Fuel tank

Wow! What a lot of information. Just want to say thanks to everyone and hope we all learned something out of this. First of all, I sold the old Merc 1000. I just want to get something more efficient. They are nice looking motors and do stand out. The boat that was swamped that I mentioned, I do believe was rated to carry that many people, though I don't know for sure, it was an open bow boat. I don't want to debate that, as I don't have all the facts. The thought of a fuel pump crossed my mind also, but have not looked into it as I have not selected a replacement motor, if it matters. The idea of running steel tubing is a good one and one that I did not think of. The tank I picked up is a used one with different set-up or fittings from the one pictured, and I did not know the hatch system/cover was even an option. Another good idea. Mine is a metal tank and I think it came out of a reinell.
My main reason for posting was mainly for information on handling of the boat. And if I could go with a heavier weight motor with the fuel in front. I think I'll just have to wait until I get a motor and go from there. Maybe throw some sandbags or something that weighs 200lbs or so and see how it goes. But then again, if that works out I plan on taking the two ten gallon tanks out that are in the back..then does that change everything again?
The best advice I've heard? Don't fool around with fuel.
Thanks for all the ideas and all of your thoughts. Sorry about the delay.

Baldy1
 
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