Sunday, October 25, 2009

Trying to avoid an "Oh Sh1t!!!" moment......

Anyone who has ever worked on a boat has had at least one of these. The work of art that won't fit through the hatchway etc. etc. As I am about to invest a bunch of boat bucks in aluminum tanks that cannot be returned I decide to mock them up, in cardboard and hot glue, first. I will see if they fit tomorrow. I did learn, however, that you should resist the urge to spread hot glue with your finger.

Question for the experts? I need to rest the finished tanks (after epoxying them etc.) on 2" wide by 1" high stringers. What should these be made of? I would like to bolt the stringers to the keel bed and then 5200 the tanks to them, so that rules starboard/kingboard.

Click here for a good article on installing fuel tanks.


rj said...

For the stringers, this is what the tanks will rest on, right? A couple ideas come to mind:

1- Coosa board (light, strong, wont absorb water, especially if you epoxy seal it). 5200 will stick.
2- Solid teak or white oak. Resists rot, not sure if 5200 will stick well.
3 - Fiberglass U-channel 3-inch wide, turned upside down. The 1/4" stuff is really strong.

I can send you some Coosa free. I got tons of 1 1/2" thick scraps and would rather give some away instead of throwing it in the bin.

Consider it a standing offer.

The Incredible Hull said...


Done deal. e-mail me at whitby42 "at" and we can set it up. I will, of course, pay the shipping.

Thanks again


Jerr Dunlap said...

I'm not familiar with Coosa Board. Teak, contrary to popular opinion, glues wonderfully and while 5200 will grab it like crazy, 5200 is not a sealer. The best way is to:
1) Completely paint correctly-sized hardwood with barrier coat epoxy or barrier coat epoxy paint system (Must use prep and primer!).
2) Drill rough screw holes (Push hard & fast and pull out with as little rotation as possible.), 1/16" oversized from max. screw thread diameter.
3) Fill holes carefully down a side, making sure to leave air escape hole, with a structural epoxy paste. While chopped fiber is strongest, it will trap air and so is not recommended here. WestSystem 406, with 422 for barrier coat is ideal. I use a straw and blow to deposit it at the bottom, then tamp it.
4) Screw carefully by hand with screw coated in grease, wipe off excess and leave screw in place until epoxy sets.
You've got a waterproof, amazingly strong screw hole, custom-threaded! When you seat the screw permanently, use a lock washer: You've turned your screw into a bolt.

The important bit to remember here is not any oil property of wood but the hardness and strength. Almost any hard wood is just fine and many are much cheaper than teak. No matter what wood or other material is used, it must be truly waterproofed. Many materials appear impermeable and aren't, over time. Screw holes are the most obvious places for rot but any surfaces that rub are also suspect, so make sure everything's fastened properly and watch out for later mountings: I prefer to stick, rather than screw workman's loops, mounting plates, etc.

The simplest is glassing a U-channel, as RJ suggested, with access holes for wrenches and bolt to it. There's a lot to be said for circulation under tanks. By the way, my favorite technique is taping one side of a box wrench, so the nut doesn't fall out.

Hope this helps! By the way, your quality is great - Vastly better than the average highschool dropout work found on boats (Doesn't that make you feel smart, now?). I'm getting a kick out of following you!
- Jerr

The Incredible Hull said...

RJ and Jerr

Way too much pressure with you two watching me. Keep in mind that, on the internet, nobody knows you are a dog (or building one).

Thanks for all the info and help.


Jerr Dunlap said...

Argh, me matey, beware what you ask for! Bwaaaah-haaaahhh-haaaahhh-haaaahhh!

Here's another consideration: Cut tank horizontally or vertically to get it to fit? If you're getting baffles, I'd go vertically: The lower tank won't ever get condensation; there won't be a horizontal shift in ballast as one tank empties and the top tank can be guaranteed to empty completely - Easy to mothball if you're not going to use it for a while. On the other hand, long tanks may just not fit around a corner. Ain't I a stinker?
- Jerr