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Installing new saddle tanks on my 22' cruiser would like less stern weight

T

TheBrain

Regular Contributor
Installing new saddle tanks on my 22' cruiser.

I’ve given up on a big long belly tank due to limited size inbetween stringers 25"an stringer height 5". Vessel came w/ 15 imperial gallon saddle tanks image.
back.png




These tanks I aquired are made in 1974 actuely older than my vessel by 3 years but are much nicer shape and material (orginal was steel go figure) each is 20 US gallons so w/ two 6 gallon reserves will be enough for a 3day cruise. so I gain a tad of deck real estate.
outside both tanks.jpg




I’m still wanting to move some of the weight forward bc I want a 130LB 10HP kicker engine.


remember I had a 15US gallon all the way aft at stern image.also opposite side two 6 gallon reserve tanks at stern. an the oil tank for the 2 stroke engine.
moller in rear3.jpg



It would be easier to not slide the tanks forward basicely having the front part of each tanks inside cabin a few feet. The front of each tank has the fill an vent, the pickup is aft.
Just enough room to slide tank inside cabins upright.jpg




If I move forward inside cabin will complicate refueling I’d be forced to fill primary tank then move vessel at gas station to fuel secondary tank bc cabin obstructs the fuel hose.



I’m in the process of installing the new tanks.

Here’s the aft of port side image.
port side initial fit need to move forward.jpg



I’ll be fabbing three triangle surports for each tank will blind reviot right though the freeboard just like the orginal tanks where mounted.
aft
aft end of port tank.jpg



The lower section of tank is like 3” an triangles up to like 7” at top.even w/ the extra surport triangle I don’t think a 3” platform is strong enough orginal platform was like 6".
the orginal tanks where secured w/ flange clamps though the freeboard.
the new tanks only have a small flange on each end at bottom of tank w/ one bolt hole. so basicely only the bottom is securable additionaly these new tanks where glued w/ 5200 on the bottonm of donor vessel.

it's the top I'm concerned w/ securing:

the top of the tank isn't yet held in place w/ the gunnal. I'm thinking to wrape top of tank w/ rubber laced to tank or maybe out door thick carpet glued to freeboard , isolating the tank from rubbing on freeboard suggestions on securing top don't want to relie on just the filler tube to hold the top in place.
aft end of port tankp.jpg

here's how the orginal tanks where secured in front an aft note they don't contact the freeboard.
orginalvfuel tank.jpg

I could glue a flange w/ west sys. gflex epoxy to tank that slides into the orginal holder not sure if glue would be strong enough even though the 2 bolts at bottom of each end is doing the majority of securing..
any constructive critizium or advise is welcomed.
 
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Something about the placement gives me concern.

The tank should be closed off from external contact so it should be covered. It also needs air circulation around it so fumes and moisture doesn't build up.

Then where will the vent lines go to?
Needs to be vented above the tank and also have a drip loop in the hose
 
AllDodge said:
Something about the placement gives me concern.

The tank should be closed off from external contact so it should be covered. It also needs air circulation around it so fumes and moisture doesn't build up.

Then where will the vent lines go to?
Needs to be vented above the tank and also have a drip loop in the hose
Click to expand...
the vent of tank is right near the fill neck about the same height. the hulls vent is also about the same height as fill neck. here's the Starcraft hull vent.
Starcraft vent.jpg

new tank is taller than orginal.Iooking at my first image will have to lower the new tank a bit.
how much lower should the top of the tank be from the hulls vent?

the orginal tank was indeed covered IIRC w/ a thin section of 1/4"plywood w/ vinyle decrative wallpaper.

what I have right now is the tank spaced off the freeboard w/ the orginal tank clamp.thanks all dodge for advising.

Fill neck gunnal rub rail hull vent.jpg
 
IMO, the "inverted U" loop in the vent hose is utopia...many installations dont have the space for it so I would say they are not essential. You do NOT want any "trap" in the vent hose.

On the vent thru hull fitting, you want the 'holes' oriented 'down' to minimize any water collection...and, if they are on the hull that gets a lot of spray, you will want to provide a shield of some kind (many people use clamshells)...

you may want to consider a pair of metal straps to retain the tanks...I would use a hard plastic (like starboard) piece at the junctions vs something like foam that would retain water...
 
Installing new taller saddle fuel tanks.

I’m concerned about the length requirements of the vent tube an it’s J/loop.

Like vent tube needs to be how much longer than the top of fuel tank? is there a rule of thumb?
vent heightp.jpg



Since new tanks are much taller, I may have to lower the tank some? Look closely at the height of orginal an new tank. I’ll make some mearsurment an make illustration of the heights of each componet.



I believe this required length is to prevent fuel from flowing out the vent an basicely blocking the vents airflow also dumping fuel.



My port vents inside tube broke replacing it w/ a plastic vent apparently it has a 360* direction? Image
new attwood vent.jpg

I can fab a clam shell (however the Starcraft orginal vents already has overhead protection but not side protection) thinking it looks like a though hull cover preventing water to roll though (example transducer cable) Will confirm this an report back.

Actuely both of the orginal vents are aimed upward an do have sreens, should I zip tie a small insect screen over the new attwood to prevent insects (mud doppers) from clogging vent?



When you say “You do NOT want any "trap" in the vent hose” your referring to the upsidedown P trap pictured in diagram,image
fuel tank setup properly.jpg

that’simiairl to the household sink which is designed to prevent stinky sewer fumes entering home. So a trap on a fuel tanks vent will hold gasoline fumes creating a dangerous potensional for explosion if a spark happens which makes a lot of sense.



That’s why you say “You do NOT want any "trap" in the vent hose”You want this vent tube completely vertical except for the 90* bend going into the vent?





The new tanks have ground attachments on tank an filler neck which I will connect to negative bus bar more on that later the priority is mount an connect both tanks at proper height.

Thanks a lot Makomark for explaining fuel tank safety
 
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AllDodge said:
ABYC
Click to expand...
lots of good infor on fuel tanks safety I saved that doc.
going back to there image of fuel vent line
fuel tank vent setup properly.jpg
I believe the filler is a tad higher than the vent BC vents under the gunnal where the fill is located on gunnal.

what my main concern is the lenght of the vent tube? doe's the length of the fill tube determine the length of the vent tube?
original tanks are much lower an have much longer fill tubes to compensate for tanks being lower.

or is the important part of this illistration the vent is lower than the fill an lenght of hose's is irrelevant?
an the vent doesn't have to be X times lower than fill?
thanks alldodge
 
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The document gets into all of what I'm listing below

Venting compliance is page 35 and says there are no recommendations, only that the vent shall be able to vent fuel up to 2 gal a minute and must not flow into the boat (overboard), and vent can be cleaned

The vent should be higher than the fill to keep fuel from leaking out when tank is full. The amount of loop is more to make sure water splash does cause water to drain into tank

The area where the tank is mounted must be vented to keep fumes from building up.

Fuel fill (gas cap) must be placed so all spillage shall not drain into boat, all goes overboard

Mounting, types of hose used, types of hose clamps, tank placements and how to mount are all specified

I know your going to do it best and safest way, but all the liability is yours. If boat is ever sold the changes can come back if anyone is ever hurt and it's determined something wasn't correct
 
AllDodge said:
The vent should be higher than the fill to keep fuel from leaking out when tank is full.
Click to expand...
above is a tad missleading shouldn't this really say "The vent should be higher than the top of tank"?
bc tanks arn't filled all the way up the tube, even if the fill tubes safety vavle wasn't installed.
thanks alldodge
 
I saw nothing in 33CFR183.5xx mandating the inverted loop...that said, if there is space, I think installing one is a prudent approach. I believe the boat is old enough that any EPA emission changes are not applicable.

you want the vent to exit the hull as high as you can get it...you want to minimize any chance of fuel being sloshed out when the boat is rolling.
 
update: the new tanks vent is jammed up agaisnt the gunnal I could grind this part of gunnal down a bit
clearance for vent tube.jpg

w/out weakening it to much, the midship area is where most of the stress takes place.

gonna lower the tank a tad for vent tubes clearance. then add a loop at top of vent tube.
vent height vent tube loop.jpg


I have some thick marine plastic same stuff plastic fuel tanks are made of. plan to glue a 90* piece at each end protecting tank from rubbing on freeboard.

after I establish height then I'll be covering either with plywood or some thin aluminum. thanks Guys for advise
 
#1. can I use a circlur loop on the vent tube? green illistration.
2.I'll glue this thick white marine plastic to the aft upper part of tank inbetwen freeboard an tank.

also considering attaching a plate to the plastic that can slide into the orginal tank mount.
plastic isolating pads.jpg
orginalvfuel tank.jpg
 
dont use the green loop as you have drawn it. you want an inverted U above the blue line...and it doesn't have to be in one plane...the idea to to eliminate any low spots (dips) that could trap fuel or water (which restricts the venting action)...

go back and look at the drawings in Post #4 - the upper right hand one and the lower one - each shows viable examples
 
makomark said:
dont use the green loop as you have drawn it. you want an inverted U above the blue line...and it doesn't have to be in one plane...the idea to to eliminate any low spots (dips) that could trap fuel or water (which restricts the venting action)...

go back and look at the drawings in Post #4 - the upper right hand one and the lower one - each shows viable examples
Click to expand...
I should have ordered the 90* type of vent. this way I could aim it's tube upward then go out tanks vent tube up tten U turn down.
should the round 360 type vent be avoided?
360 degree vent.jpg
like will underneth water splash into it. the orginal vent had two overhead screened openings which seams to prevent water from splashing into vent.my rubrail seams to be overhead protection.

the tanks are clean on the middle chamber
inside tank1zero corrosion.jpg
inside tank2 clean.jpg

however I feel a bit of dust inside pls suggest a way to clean flush out the dust I was planning to pour half a gallon of fuel in then shake it up then drain.

was also gonna use a small extrenal filter directly outof tank I've read to never use this type of filter on a regular basis.I do have water fuel separator an a spin on fuel fliter at engine.
extrenal fuel filter.jpg


edit: I'm confussed on the keyed fuel cap like won't the key be overboard the first use?or doe's it dangle from a cord
keyed fuel cap.jpg
thanks Makomark.
 
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I'm now thinking if the vents input tube is turned upward the actuel vents will also turn basicely turning the vents either to 3 or 9 oclock. so I maybe forced to get the 360* type?
 
The 360 type of vents are ok...in my opinion, there isn't a 'perfect' vent for any situation...they will all have tradeoffs.

When we had the 'splash' issue, the solution we used was a "plastic cup" that I had a machinist spin on a lathe...similat to the end result of the fist pict in post #18 but ours extended out past the center 'button' about a 1/4".

On the key - most use a key fob that floats - that way it isn't cluttering the deck handing from a bungy cord...I'd think you could also use an elastic wrist band to keep the key dry.

As far as the dust in the tank - I'd probably be inclined to use some alcohol (cheaper than fuel and no "EPA Concerns"...you could always try compressed air if the tanks are still out. Probably not enough to worry about for the near term.

On the filters - I would stay away from the type in your pics and just stay with the spin on filters. Will keep the insurance agents happy too.
 
makomark said:
The 360 type of vents are ok...in my opinion, there isn't a 'perfect' vent for any situation...they will all have tradeoffs.

When we had the 'splash' issue, the solution we used was a "plastic cup" that I had a machinist spin on a lathe...similat to the end result of the fist pict in post #18 but ours extended out past the center 'button' about a 1/4".

On the key - most use a key fob that floats - that way it isn't cluttering the deck handing from a bungy cord...I'd think you could also use an elastic wrist band to keep the key dry.

As far as the dust in the tank - I'd probably be inclined to use some alcohol (cheaper than fuel and no "EPA Concerns"...you could always try compressed air if the tanks are still out. Probably not enough to worry about for the near term.

On the filters - I would stay away from the type in your pics and just stay with the spin on filters. Will keep the insurance agents happy too.
Click to expand...
what type of alcohol to rinse out tank. plan to reuse the fuel filler caps that came w/ tank the key is one more thing to keep track of an probably lose.

this inline filter is just tempuary for just first tank. my new engine is fuel injected so I wanta make sure the fuel is clean an water free. actuely older versions of this engine had these inline filters previous to the now spin on type.

the plan I had glueing the plastic tabs on failed miserably I basically have to shove this tank into position tabs broke off first try, new plan for preventing the tank rubbing on freeboard is to use thick heavy duty sponge taped directly to freeboard. thanks Makomark
 
As far as the "rinse" goes, I would use whatever you have on hand that will evaporate completely...stove fuel is what i have a good quantity of...nothing magic about it.

As far as mounting the tanks, I use neoprene rubber straps, glued (tape usually won't last) to the structure and straps to hold thing in place...looking at the last picture of the outside of the tanks, probably two vertical straps if you have mounting points that will keep things tight.
 
I've managed to mount the tank to the wooden platform w/ a 1/8" bolt though tanks flange an wood. plan to 5200 bottom of tank to wood. wood is bolted to each triangle brace which is rivoted to freeboard. still figuring out how to secure top of tank. mite be able to cran more wood inbetween the decortive part of gunale the brown piece.
not seeing a way to use strapes. mite be able to reuse the orginal tank holder, by JB epoxying a flange to fit this only on aft part of tank.

I'm hoping theres just enough room to aim up the new vent w/ its 90degree tube in order to get the upside down U in vent tube. here's star side orginal vent.
vents 90 degree tube.jpg
 
the inverted U doesn't have to be "vertical", it can be tilted. the "key" is to have a constant slope from the high point of the vent hose hose downward on each leg, that way no fluid can get trapped in either leg...

attached is a quick and dirty drawing...
 

Attachments

  • vent hose orientation.pdf
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I think i'll be able to getaway w/ the yellow alternative route. haven't test fit yet but just looking at the new 90* vents tube is way to big. didn't even notice it being advertised as 3/4" hose.
I need

5/8" inside diameter Hose.bc I mearsured tanks vent out put diameter as 5.8".​

​



proper size 360 degree vent.jpg

next I need to know what is portside A or B when this stuff is made in USA there won't be a lose of translation.
or is there star an port vent? bc they say fit type is universal who knows what there referring to maybe where it bolts to.
the bot is useless as usale ok I just figured it out a is a screened vent an B is the 360type .
confussed bot on fuel vent.jpg

I'm hoping I can reuse the orginal vent on star side.

still need to finish waterproofing tank platform w/ epoxy an 6oz glass, plus fab an mount surports directly into freeboard.​

thanks makomark for diagram an advise.​

 
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