Internal Fuel Tank

[HeaveToo]

I was wondering if anyone has heard of or has added a fuel tank that is permanently installed in the boat.  I know that this is done with the diesel engine version of the 23 and they put a 10 gallon tank in it.  Why couldn't this be done with the outboard version and have a proper vent for the fuel tank?

They do this in power boats all of the time.

[brackish]

I haven't but sure you can.  Buy an approved below deck tank and properly and safely install it.  And install a vapor blower kit to vent the bilges before using your stove or any spark producing electrical equipment. And install a Racor filter because that gas tank is going to condense water and you'll have no way to get it out but to filter it before it hits your outboards carb.  But why on earth would you want to.  You loose the portability of the outboard fuel tank, and the ability to fill your tank at a non-alcohol added gas station, and use it up in another application instead of letting it degrade. 

I had a Columbia 8.7 with an Universal Atomic four gas engine.  The A4 was a really wonderful engine, smooth, quiet and adequately powerful.  However, I had more carb and fuel problems with the fixed gas tank than I've ever had with small outboards with remote tanks. 

[HeaveToo]

Well.....There is the reason that this isn't done!  I was wondering about this. 

I was thinking of this for the additional fuel capacity. 

[NateD]

Plus you have placement of the tank. The boat is already stern heavy, adding a large tank back there isn't going to help trim the boat any.

In dead flat calm water I'll get 18 mpg with my Nissan 9.8hp 4-stroke at about 5.5 mph. I haven't tested it long distance again the wind yet. But at that rating my 6 gallon portable tank gives a range of just over 100 miles, more than enough for coastal cruising.

[HeaveToo]

What brand of 6 gallon tank fits in the locker for fuel?

[brackish]

What brand of 6 gallon tank fits in the locker for fuel?

http://theoutboardwizard.bizhosting.com/_177001_universal_duratank_6_gallon_fuel_tank.html

I bought mine at Defender, got a much better deal, don't know if they still carry them.

[breeze]

The tank that the 23 uses is a 7 1/2 gal and is mounted on the aft bulk head
This will improve the balance of the boat, you will be moving the weight about 5ft forward and 2ft lower

David

[brackish]

The tank that the 23 uses is a 7 1/2 gal and is mounted on the aft bulk head
This will improve the balance of the boat, you will be moving the weight about 5ft forward and 2ft lower

David

You're talking the diesel tank right.  I'm sure it works great with that diesel motor located amidships with the battery bank on the opposite side to offset the weight.  That location is not going to help much with a gas outboard.  My 23 already lists a bit to port because of the motor and with 7.5 gallons of fuel on the port  side that would be worse and it is still aft of the centroid.  Just doesn't make sense for so many reasons with gasoline.

[breeze]

Yes I did install a diesel and I didn't put the tank near the port side hull.
I installed it under the cockpit, there is only 4in of the tank beyond the cockpit bulkhead.
The fill and vent lines run to the stern along the cockpit bulkhead.
The battery was moved forward of the head.
The fuel tank is the only thing that has any weight aft of the bulkhead.
I try very hard not to add anything on the stern of the boat.

David

[brackish]

Yes I did install a diesel and I didn't put the tank near the port side hull.
I installed it under the cockpit, there is only 4in of the tank beyond the cockpit bulkhead.
The fill and vent lines run to the stern along the cockpit bulkhead.
The battery was moved forward of the head.
The fuel tank is the only thing that has any weight aft of the bulkhead.
I try very hard not to add anything on the stern of the boat.

David

Well I misunderstood, the factory location for a diesel tank is behind the bulkhead on the port side.  But you're using this tank for gasoline?  Fairly sure  the ABYC requires a blower system for below deck gasoline storage, how did you handle that.  Was your insurance impacted?  How did you get it in there?

[breeze]

I have diesel in the tank
You are correct about the tank location, I mounted my tank closer to the centerline of the boat
I don't know why you would need a blower the fuel tank it is vented to the outside and the fill is outside.
A blower is definitely required with a gas inboard.
When I was younger we had a Columbia 28 that had a built in tank with a outboard without a blower.
This was a long time ago and the laws may have changed.
David

[brackish]

I have diesel in the tank
You are correct about the tank location, I mounted my tank closer to the centerline of the boat
I don't know why you would need a blower the fuel tank it is vented to the outside and the fill is outside.
A blower is definitely required with a gas inboard.
When I was younger we had a Columbia 28 that had a built in tank with a outboard without a blower.
This was a long time ago and the laws may have changed.
David

This thread was about adding a below deck tank in order to get more fuel capacity for a gasoline outboard and whether that makes sense.  Diesel is a completely different situation.  You are not required to have a blower system for diesel because a leak cannot build an explosive mixture of fuel vapor/air.  You are required to have the system for below deck gasoline because a leak in the tank, fuel line, or any part of the system that can allow gasoline into the bilge or below decks can create an explosive mixture.  That (liability) is the primary reason (but not the only reason) that one hundred percent of sailboat manufacturers have switched from gasoline auxiliaries to diesel.

I suspect you were required to have it on the Columbia.  You just got lucky.  You were using an outboard and most explosions occur from starting the inboard, but can occur from any below decks spark source when the combustible mix is present.

But I'm interested in your setup.  Did you buy your boat new and have the factory set the tank at the amidships location?  Or was it an old diesel Compac that you relocated the tank?  Certainly, tank, motor, and battery bank all in line and somewhat forward would be the best situation for trim when compared to a heavy outboard hanging off the stern.

[breeze]

The boat is a 1982 it had an outboard motor bracket, but there was no motor.
I had a 4hp outboard from my dink, used it to get to a local marina.
That was the only time I used the outboard, I purchased the 1GM10 and all the parts needed plus new rigging, main, furler, pulpits, and bow sprit.
Drilled the hole for the shaft glassed the cutlass bearing
Epoxied the bottom and panted the hall.
Had the boat out of the water for a long time, but it was time well spent in my opinion.
David

[Bob23]

David:
   Interesting conversion. I may pick your brain about this. Can you share the total cost of the diesel conversion only?
Bob23

[brackish]

Wow, what an undertaking.  I would also be interested in more detail.  In thoughts about the best next boat, I've sometimes  felt it would be a 23 pilot house to get standing headroom, and enclosed head, and longer cruising range.  New sticker shock being what it is on that model, I've thought about a conversion of an old CP23.  Mine is too new to start tearing into, probably would be better to sell as is and use the proceeds for the conversion.  Diesels are few and far between, and often pricey, so taking an old outboard model, converting it to diesel and adding the pilot house all at the same time kind of makes sense to me.

Was it difficult to do the motor/shaft/cutlass bearing alignment?  Did you take the tank in from the cabin? Didn't happen to keep a picture log of the conversion did you?

Maybe start a new thread since this one has been shamelessly hijacked.