Bulging Fuel Tanks

[Casey]

Gee's, I love it:

"...as we wander down that golden road to geezerhood, and thus why we all wind up as old gnarly farts joyously fiddling around in boats..."

Priceless.

Thank you!

Casey
C-Dory Naknek
(50% Geezer; 50% Gnarly ... but getting There!)

[Sawdust]

Wow! I love it too. If only I could remember my name and sign this...er.... this what? Today's me day. 85! Wow .... soon catch up to Tyboo Mike.

[Sea Wolf]

Dusty-

85 and still messing around (in boats, that is)! I love it! Congratulations!!! You're the Role Model and the "Poster Child" of this wonderful community. Have a brew or two and enjoy yourself on this special day! Joe.

[rogerbum]

[Mighty Bite]

My new 25 gal tanks rolled in so its time to decide how I want to do the cleat/retainer treatment for them.

Lateral cleats will be mounted on the underside of the splashwell and bear on the top edge of the tanks.

For the front cleats I will use either plan A, which is to epoxy SS bolts in the floor and in doing so enlarge the cavity sufficiently to accept a generous amount of epoxy and thereby (hopefully) enhance the strength and holding base for the bolts. Pretty much as Ken on Cavu did, except I plan on using stainless angle for the cleats as opposed to the starboard material.

Or....... epoxy threaded inserts in the cockpit floor, here again, within an enlarged cavity, and using ss bolts to secure the stainless steel cleats to the cockpit floor. This latter option may be rendered moot if I'm unable to come up with adequate threaded SS inserts. I'm ready to pretty much guarrantee there is nothing of the kind available in lovely Fairbanks, AK, as I think I've exhausted the local possibilities.

I do have the luxury of a little time however, as it is still too cool to mess with epoxy outside.

[C-WEED]

Maybe there has been a tank failure and the poor SOB never lived long enough to tell anyone about it. I shudder at the thought of that fuel getting loose in the cockpit. I have noticed the bulge in my tanks and the first screws in the front startboard have kinda pulled. If they bulge at rest they must really flex in and out when you hit rough water. The front starboard seems like more of a protector of the front of the tanks than any real solid mount. Has anybody used a buckle strap going around the circumfrence of the tanks? One of those small ratchet straps would really pull up tight. Seems like getting this good and tight when the tank is near empty would help stemmy the outward expansion of the tank without a modification to the boat.

[Larry H]

I seem to recall that the bulging in plastic tanks is not caused by the weight of gas in the tank, but it is caused by a reaction of the tank with gasoline.

Greg (Red Fox) installed plastic tanks made by another manufacturer and the instructions said to alow for 10% expansion.

Does anyone know if the bulges come and go with the amount of gas in the tank?

Has anyone had to reposition the cleats more than once due to bulging?

[Mighty Bite]

My feeling is that there is going to be some bulging and expansion on the standard C-Dory tanks, whether they are the older 20 gal tanks or the new 25 gal tanks. Hopefully, it will be less with the new tanks. That doesn't bother me and I don't feel it is a big problem. A little space can be allowed to accomodate that.

I do feel that the system for cleating and holding the tanks in place is one that can and should be improved. It is simply to much to expect the factory cleat system to hold up over time without problems of the cleats and screw upsetting and allowing water entry to the balsa core. If the tanks are removed for cleaning, access to the area, or replacement the problem is exacerbated, as the fiberglass is not receptive to a lot of
"screwing around" (no pun intended).

The only anchor we have for those screws is the relatively thin skin of fiberglass that makes up the cockpit floor. I don't know if it would be possible to mold in a solid band of glass across the cockpit floor where the cleats are or not, but I look for some changes from C-Dory somewhere down the road as it seems like such an obvious need.

In the meantime has anyone used SS threaded inserts and bolts to anchor their cleats to the floor.

[Levity]

Back to the original topic (bulging tanks) with a new question.
When resetting the StarBoard onto the cockpit floor why drill new holes? These holes create an opening for water to enter the C-Dory's balsa core; water is to balsa core what kryptonite is to Superman. I would like to bond the starboard to the cockpit floor instead of drilling and using screws. Adhesive Methods and Technology Inc. claims their 7540AB adhesive will make a powerful bond between StarBoard and fiberglass. Using the shim method described in this thread would allow for any future adjustments in spacing between the permanent StarBoard and the tanks. Making the Starboard permanently attached to the cockpit floor will not interfere with removal of the tanks if removal is needed in the future. This sounds like a good fix but before I go this route please give your thoughts on the merits or hazards of this concept.
Mike 'Levity'

[Sneaks]

I seem to remember looking into that 7540AB "special adhesive" and the methodology included carefully flame treating the starboard. It didn't look that easy to get done right the first time, especially for an amateur.

Don

[Adeline]

3rd Byte, You asked about threaded inserts. If you're not already done, here's what I've learned. West Marine has them, $5.00 each http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&productId=3856 . Also Yardley(4 varieties) http://www.yardleyproducts.com/mold.htm . And Pennfast http://www.pennfast.com/fastening_products/prod_desc.php3?cat=SI+Inserts+for+Plastics . I'm planning on using 1/4"-20 on my 25 upgrade.

[CAVU]

Levity,
I just finished installing my tanks today. I used the bolt epoxied in the floor method. I also considered trying to bond the starboard to the floor but decided to use a more simple method. I think if I had it to do over, I would simply epoxy a wood strip to the floor and paint it white. The more I live with starboard the less I like it. My previous boat (Arima) had the whole cabin built of starboard. Screws were always pulling out, the material is soft and fairly porous, and stains easily. Because of the light surface texture, fish blood and stains are very hard to clean off once they dry. Just my 2 cents.

[terraplane]

I'm sure i'm not the only one awaiting the arrival of a brand new 22 to wonder if I can expect my fuel tanks to be rattling around back there in a short time. With normal use, is it to be expected that one will have to correct this? When? Would appreciate input from Jeff at the factory and Les...and anyone else.

tom

[Levity]

Don,
Thanks, the flame treatment does sounds like it will require practice to get right. Larry Doring from Adhesive Methods explained the process in detail which will help in attempting to get it right. There will be practice trials on some spare StarBoard before the application of the adhesive to the cockpit floor. Starboard isn't easy to clean but it is rot proof.
Where possible the starboard will have bolts and nuts for fasteners to avoid the tendency for screws to be pulled out. Thanks again for the tips.
Mike 'Levity'

[dogon dory]

Sorry, Folks - Post Deleted By Author