Geronimo's motorbox

Designs for inboard or outboard power

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bobinpowayca
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Geronimo's motorbox

Postby bobinpowayca » Tue Oct 31, 2017 2:10 pm

Well I'm getting close to finishing - the motor box was a challenge for me but I think I've got it figured out. I've never had a power boat or known anyone with an outboard boat. I bought a motor and the plan is to trailer my boat to them and have the motor installed, so if I don't have holes in the right places there'll be more labor involved.
Here's one question I have about the fuel tank. I went ahead and built the bulkhead using frame 1. Before assembling it I cut three holes in it- the middle for bilge access, starboard for the battery and port for the gas tank. As you can see in one picture my steering wheel will be on the left. So one issue will be whether both the steering and motor control cables will both fit one one side (the left) or will I need another set of holes on the right.
Other question is (now that I have already cut the hole) is whether the tank will fit thru the hole. The top will be covered with a deck so the only access for gas tank and battery will be the opening in the bulkhead. And now that I've looked at some boat gas tanks on line it looks like I better make the hole bigger.
So one question is how big a tank do I need? I will have a 90hp motor - what would be a practical size tank - I see 3gal and 6gal.
Also, do you generally leave the tank in place or drag it out of the hole to fill it with gas? I was planning on jump seats in front of these holes.
I'd appreciate any ideas you folks may have on how you do your gas tanks for boats like mine. Thanks, Bob
ps, also wondering if gas tank should not be on same side as where steering and motor controls are?
Attachments
IMG_1185.JPG
need bigger access for gas tank
IMG_1184.JPG
blurs on hole for fuel tank
IMG_1171.JPG
steering & controls both on left?
Bob
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Built the Glen-L 17 (1988), Geronimo under construction (2013)
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vupilot
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Re: Geronimo's motorbox

Postby vupilot » Wed Nov 01, 2017 4:50 am

With a 90hp motor you will want more than a 6 gal tank. You might burn as much as 8 or 9 gal an hour a full throttle. Unless you use multiple 6 gal tanks I wouldn't plan on pulling the tank out to fill. A 15 gal tank would weight about over 90lbs.

bobinpowayca
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Re: Geronimo's motorbox

Postby bobinpowayca » Wed Nov 01, 2017 8:52 am

vupilot, thanks for the wake-up call. I had no idea it would need that large a tank. This will change things. I would like to see how any of you have set up your fuel tanks for a boat likemine. Thanks, Bob
Bob
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Built the Glen-L 17 (1988), Geronimo under construction (2013)
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JimmY
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Re: Geronimo's motorbox

Postby JimmY » Wed Nov 01, 2017 9:24 am

Do you have the option to put the fuel tank up front? They make permanent tanks shaped for the bow. You would then have a filler on the front deck.
-Jim
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DrBryanJ
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Re: Geronimo's motorbox

Postby DrBryanJ » Wed Nov 01, 2017 10:00 am

Bob: I am going to use a 90hp. I plan on a Moeller 19 Gallon Bow Fuel Tank 032819. 32.00″L x 20.75″W x 12.31″H. There could be an issue with the filler neck, but I think it is workable. I think this gives me about 3hrs wide open throttle.
Bryan

Building a malahini "Mona Lisa"

My wife said "If I build a boat, she's getting a divorce."

bobinpowayca
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Re: Geronimo's motorbox

Postby bobinpowayca » Wed Nov 01, 2017 10:07 am

Jimmy, that may be an option, I don't know. I have a lot of room on each side behind the bulkhead, just made the hole too small. I could put a bigger tank in that space (taller too) but since I am putting a plywood deck above it, the tank would not be accessible - I'm thinking I need to be able to remove it or fill it. I don't know how much trouble it would be to run a fuel line aft.
However, if the tank can be in there "permanently", is that okay? i.e., maybe I could put a hole in the deck for filling the tank, another hole thru the motorwall side for the fuel line? Then where would that bulb you squeeze for priming it go so it would be accessible?
Thanks for any help!! Bob
Bob
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Built the Glen-L 17 (1988), Geronimo under construction (2013)
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PeterG
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Re: Geronimo's motorbox

Postby PeterG » Wed Nov 01, 2017 1:54 pm

Bob you would put the primer bulb in the motor well between the engine and where the fuel line enter the motor well. No way around making a custom fuel line but that's not a hard thing. Not sure what to suggest for the fuel tank issue, you did a really nice job with the bulkhead but maintainability/access to the tank is a concern, especially since we all know how reliable tank level senders are...

DrBryanJ: Something to ponder, would a 12 or 13 gallon tank be too small for your purposes in your Malahini? I ask because a full 19 gallon tank is significantly more weight in the boat, about 44 pounds more (about 75 lbs for full 12 gal vs about 119 lbs for full 19 gal). The extra weight with the larger tank will cost a performance penalty compared to the smaller tank.
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bobinpowayca
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Re: Geronimo's motorbox

Postby bobinpowayca » Wed Nov 01, 2017 3:55 pm

Thanks for the suggestions. Obviously I will need a larger tank. Since I plan on covering the area around the motorbox with a deck (screwed and glued like the rest of the deck) the only way I can put a tank there would be permanent - I'd have to wreck the deck to get it back out.
So I like the idea of the bow tank,that would be removable if I really had to. Only concerns there are running a fuel line back to the motor. Also I put in a hatch so the grandkids could sit up there and look out the bow - I wonder if that would still be safe for them sharing a space with the gas tank or if there'd be room for them in this area under the foredeck. It'd be nice to pull up to a gas station and have a filler tube on the deck rather than try to fill a tank in the boat. Thanks for the help folks. Bob
Bob
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vupilot
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Re: Geronimo's motorbox

Postby vupilot » Wed Nov 01, 2017 4:58 pm

My tank is in the bow and the fill is on the deck just forward of the windshield. My rubber fuel line runs down the starboard side and my electrical runs down the port side. The hard part is hiding the line from sight. The primer bulb on mine is mounted right where the fuel line passes by the drivers seat so I can lean down and pump it once or twice before turning the key to start. When my fuel pump diaphragm was going out years ago it was nice to have the primer in a location where I could reach it while driving.
construction complete 008.jpg

bobinpowayca
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Re: Geronimo's motorbox

Postby bobinpowayca » Wed Nov 01, 2017 7:40 pm

Thanks vupilot, that looks like a really clean installation. It looks like a tank in the bow is the way to go - maybe good for ballast up front too - my thought for a gas tank assumed it would sit next to the motor so I hadn't considered putting it up front. So there's not much pressure loss running the fuel line that distance? By the way where did you get your fittings, fuel cap etc for filling the tank? Bob
Bob
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chugalug
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Re: Geronimo's motorbox

Postby chugalug » Wed Nov 01, 2017 11:15 pm

:D Just gotta add my two wooden pennies-I bought my Moeller tank and all the fittings from "Jamestown Dist."I got a 20 gal for "Chug" It's mounted permanently in front of Helm.Water tanks and waste water tanks on the other side. :D
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hoodman
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Re: Geronimo's motorbox

Postby hoodman » Thu Nov 02, 2017 7:44 am

Bob, this is the tank I am planning on using in my Geronimo. You'll want to measure to be sure but I am planning on putting mine in the same location as you.

https://www.amazon.com/dp/B000MTCR8W/_e ... IX1LS2ML3L

bobinpowayca
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Re: Geronimo's motorbox

Postby bobinpowayca » Thu Nov 02, 2017 2:06 pm

First thanks a lot everyone, nowhere else could l have gotten all this information than this forum.
Matt, yes that's where I wanted to put my tank, but unfortunately the tank you got is just too wide for my space -I've already built the motorbox and that would be just too much demo; however, I see Moeller has a 14 gallon tank that will be a perfect fit - I'd just have to cut out a cleat to get it in. So I think that is the tank I'll get. The idea of a bow tank was a good idea, but the whole idea of the hatch I put in was for the kids to look out of so I think I'll go with the tank next to the motor and carry a 5-gallon can under the motorbox, one of those flat ones. Just wouldn't look good for them to sit on the gas tank. Also the fill cap will be on the same side as my truck's. :D Bob
Bob
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Built the Glen-L 17 (1988), Geronimo under construction (2013)
PBR support (1968)

bobinpowayca
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Re: Geronimo's motorbox

Postby bobinpowayca » Thu Nov 02, 2017 7:03 pm

I gotta think about this a little more. From what you guys are telling me about how much gas you're using with a 90hp motor, a 14 gallon tank won't push my Geronimo for very long...Bob
Bob
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Built the Glen-L 17 (1988), Geronimo under construction (2013)
PBR support (1968)

obd
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Re: Geronimo's motorbox

Postby obd » Thu Nov 02, 2017 7:57 pm

Bob, I am building a Malahini but have been boating in a 18.5 ft Sea Ray bowrider with a 115 hp 4 stroke Mercury for 12 years. It has a 20 gallon tank. It depends on what kind of boating you are planning but 10 - 15 gallons of fuel has always met my needs, usually a full day of tubing, skiing, and cruising the lake. I am planning on a 12 gallon tank for the Malahini(maybe smaller). Hope this helps. Bob


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