b-25 Fuel Tanks

[Waytooslow]

I am redoing a 63 B-25 and it had aluminum saddle tanks outside the stringers with a fill on each side. I had assumed that the tanks were just replacements for the original fiberglass units. Both tanks are now bad and will need to be replaced.
So my first questions is were the saddle tanks the original setup?
The tanks appear to be about 40 gals each which is a little small. I have them out and have a quote from RDS that is reasonable.
Does this sound like about the right gallon capacity? Looking at a 1963 brochure is says 45 gallons total?
I really don't want to get into cutting the deck etc. for bigger tanks as this is boat is in pretty good shape structurally. I think I can live with the limited capacity as I will only be running about 100 miles per leg.

[CamB25]

63 has twin tanks on either side of the center stringer. 40 gallons each. The OEM tanks were fiberglass.

[Waytooslow]

CAM thanks--you are correct I meant on either side of the center stringer inboard of the center stringer. What did you do in your build?

[CamB25]

I took the cut, hack, chop, build, re-build, tweak, declare victory path...single tank, dual fills and vents, 129 gallons. It requires a significant amount of work to expand the stock tank cavity. You might look for a spot for an auxiliary tank or two if you want more capacity.

Cam

[neil]

My 64 moppie had twin fiberglass tanks,45 gals each,replaced them with a single one hundred with dual fills

[Joseph Fikentscher]

I have 2 alunimum tanks 50gal each. Vdrive inboards.

[Raybo Marine NY]

You can get another tank under the cockpit a little more forward, then you will need a set of selector valves

[HotSpot]

My 63 moppie has what appears to be the original fiberglass 45 gal tank on the starboard side, mounted between the stringers. There’s no evidence that there was ever a tank on the port side. Just a lot of empty space. Kind of matches the brochure description.

[Lars]

This is the OEM 2x40 gallon fiberglass tank setup for B25 (not mine - borrowed photo). As far as I have been able to establish, all V-drive varieties of the B25 used these tanks.



Question for Cam and those of you who have modified: I checked tank availability with Danny at High Tide, and they only sell a single 80 gallon tank designed for the B25. Single tank means chopping away the centre stringer - and makes me feel a bit reluctant. What are your thoughts (and experience?) on this? How much reinforcement is needed in place of the stringer?

[Raybo Marine NY]

single tank in that spot that housed 2, and 2 saddle tanks
total of 3 tanks can be fitted

the saddle tanks will be wedged shaped

[ktm_2000]

When ethanol came through I removed the original tanks, chopped out the center stringer and made a flat base for a larger tank. There is another smaller stringer inside the main hollow fiberglass one (tough to describe -see pic), during that time I left the fiberglass one level with the top of the internal stringer and then created a 3/4" plywood panel with beveled outer edges in order to maximize the contact area and spread out any load placed on the hull. I Glassed the underside of the panel before installing then bedded the beveled edges in 5200. The whole thing was glassed down. Knowing that I wanted a full re-do of the boat and wanting more fuel, I never had a tank built and used a pair of 28 gallon tanks for many years.

I am now doing a conversion to outboards and have cut out the original battery boxes to make the fuel tank area larger by extending the flat fuel tank base panel, with the extra space I am hoping for a tank holding @140 gallons.
original config
https://photos.app.goo.gl/HM4MxpbEvJyhsqBz6
After
https://photos.app.goo.gl/WA2DMvAReuv6QgPy9
with 2nd insert piece (waiting for warm weather to glass in)
https://photos.app.goo.gl/niJ2hW1RQZjgJb2UA

[CamB25]

Lars,

That picture is not a B25 in my opinion. At least I've never seen tanks like that or stringers like that.

As far as the fiberglass center stringer, Bertram removed it (at least in the tank area) in later years..67? and used a single tank. It is my understanding that only the early boats had the twin tanks, but I could be wrong...just ask my wife!

[HotSpot]

If helpful in any way, here’s what a single original fiberglass tank placement looks like in a 63 B25. Markings on the tag are illegible, so unsure if 40 or 45 gal. Pardon the grimey bilge.

https://photos.app.goo.gl/HJDYYD4RJ5Sd8Uw99

[Lars]

Cam,

Definitely a B25. This is a late model regular US-built Moppie with V-drives. The tanks and stringers are identical on my B25 Riva.

Perhaps only the V-drive versions had the quirky forward tanks? I thought they all did, and that the large central void was storage - but HotSpots pic suggests otherwise.

Edit: I get it. ktm_2000's pics are clear. A much easier place for tanks, as you don't have to deal with the shape of the forward deck depression. This area is full of engine for the V-drives. Could have been a really nice storage area though.

The forward tank placement adds to the weight redistribution already caused by heavier engines three feet or so further forward on the V-drives. That goes a way to explain why the ride is so different.

[Joseph Fikentscher]

My '68 has two tanks and a center stringer. V-drive version. Tanks are under the cabin stepdown.

[ktm_2000]

I originally had 2 of the tanks that Hotspot has shown, on my boat they were labeled 46 gallons each so boats with that config should have had 92 gallons originally. I saved the bronze fill and pickup plates as well as the bottom ring that they bolt to if anyone wants them. Bertram bedded the tanks in some type of tarpaper and years of wet bilge + fish guts broke down the tar paper to a gooey smelly tar like liquid. When I took my tanks out I threw up due to the stench and it took lots of hours to clean it all up.

[CamB25]

The V-drive boats are definitely a different animal!

Here's a picture of my OEM tanks 63 sport convertible:
https://www.amazon.com/photos/shared/tq ... 5NPXQFRTiE

[Waytooslow]

Here is a picture of the tanks that came out of my boat. Mine are obviously the normal B-25's one bay behind the bathtub.

Lars how do you get your images to display without the URL?

https://www.amazon.com/photos/all/galle ... pMoeCOGxFA

https://www.amazon.com/photos/all/galle ... qBXTNMfHfA

Sorry original link deleted due to technical problems you will have to contact CAMB25 directly for the TuTu pictures.

[CamB25]

Here is a picture of the tanks that came out of my boat. Mike are obviously the normal B-25's one bay behind the bathtub.

Lars how do you get your images to display without the URL?



[url]]

Wild. I clicked on this link and my entire photo library came up...scary. Did you guys see my photos, or your photos, or did you get the sign-on screen? When I signed out of Amazon Photos the link sends me to the sign on screen. As reference, that is not me in the pink TuTu and high heels, I swear!

To share photos with Amazon, you need to click the share button on top and then select "get link". Copy and paste the link into your B31 message. I don't know how to embed the image like others are able to..

[HotSpot]

The V-drive boats are definitely a different animal!

Here's a picture of my OEM tanks 63 sport convertible:
https://www.amazon.com/photos/shared/tq ... 5NPXQFRTiE

Cam, Thanks for showing that photo with both tanks. I am really intrigued now. (And didn’t even see tu-tu pics)

Anyone know if twin tanks were an option, with a single as standard? From what I can tell, there was only ever a single in my ‘63 sport convt.

[CamB25]

My owner's manual from Bertram doesn't mention single tanks. Are you sure yours is a 63? Have you found your hull tag - see photo: https://www.amazon.com/photos/shared/xG ... zesbcocBQi

Cam

[HotSpot]

Yes, the tag identifies it only as 25-109.

https://photos.app.goo.gl/5HNpNp7rhnQRpEkm7

Early production boat?

Another interesting thing is that it is a port side helm.

[ktm_2000]

must be, mine is considered to be a 64, hull number 25-455 and was built in late 63. I have a tag that is very similar to Cam's on the center stringer under the cabin hatch.

[Joseph Fikentscher]

I have not found the tag yet on my '68.

https://www.dropbox.com/s/cnm1divnpgni7 ... 3.png?dl=0