Fixing a leak in a Genisis Portaboat Seam

In preperation for the epic trip to Pronghorn Lake in three weeks with a couple friends, I pulled out my portaboats. I have two models, the older model is symetrical and shaped like a drift boat and the other has a flat transom (the Genesis). Last time out, I noticed a really slow leak in the seal between the transom and the hull. After researh on the internet, I found this solution:

How To Fix A Possible Leak in a Porta-Bote Genesis Series

1- How To Test: With boat opened and raised on a rock or table, rear
seat plus transom inserted, pour a gallon of water into rear of boat
and tip the rear of hull downward so water is exposed to rear seams.

Watch where water comes out. If it really does leak, it will be the
end of the center seam at the bottom of the boat (keel tubing).

2- How To Fix: With boat open, rear seat inserted. Insert transom
(but, not all the way down to bottom of hull). Stand outside hull.
Insert 3M 5200 Adhesive (available at Home Depot, West Marine,
etc. into outside rear seam at the very end of the exposed center
hinge. This is where the black neoprene “Y” shaped gasket is
exposed and where any water can come in. Squeeze the tube
so that enough finds its way into the hinge.

Now, from the inside hull do the same at the very bottom rear
center where the seal is exposed. Lift up the black seal, clean
under it with alcohol and squeeze the sealant under the seal
on both sides of the hinge.

3- Important: Wait 5 full days for the 3M 5200 to cure before you
attempt to fold up the hull. After this time, rerun the same “leak test”.
This material expands up to 900% and will permanently seal the
Porta-Bote hull.


16 thoughts on “Fixing a leak in a Genisis Portaboat Seam

  1. New question.
    Any suggestions for smoothing out hull scratches caused from years of dragging over stones etc.\
    Can I use rubbing or polishing compounds.
    I’ve tried various grit sand paper but they just seem to dull the finish and not do much for the scratches and
    lite gouges.

  2. I have had 3 if these boats all lasted about 12 years before any leaks. The 3m product that used to fix the leaks is not made any longer so now I have my biggest leaks in bottom of transom. 2 years ago while in the water I applied Marine Hand Moldable White epoxy Putty Stick to the larger hole in the bottom center of transome on out and inside and fixed the leak over night while in the water. Last year before putting the boat in the water I cleaned the all around the bottom of the transom with rubbing alcohol and applied White Flex Glue all along bottom of transom, then taped the outside of the seams of the that area with the Black Flex tape, after this I had less water leaks than ever.
    This year after unfolding the Porta-boat getting ready for a trip It leaked when testing before putting into water so now I will clean off all the tape and glue and redo, if this works I will keep the boat together and not fold up again and see if it will last one more year. This boat is well over 12 years old.

  3. I have a twelve year old, 11 ft Genesis IV, Porta Bote with a small crack at the middle seam of the transom. Has anyone ever tried “Flex Glue” or Flex Tape” (as seen on TV) to repair this.

    • My friend and I have successfully repaired a 6″ in length 5-6 stitch separation of the keel on a 10 ft. Porta Bote located below the front Bow water line.( Damage caused from running into Garage header), 1: Do Not Assemble Bote & work on a stable platform. 2: Carefully remove poly pipe from keel. 3: clean leak area using cleaning solvent or Iso. Alcohol around Polypropylene joining material & stitching. Dry the area.
      4:observe the condition of the closed cell membrane (located and stitched between hull material of keel joining) leave it in-tact.t torn or broken.!
      5 Purchase from a Automotive upholstery shop a small piece of closed cell membrane (if needed), and automotive/marine high heat adhesive “used for seems in environment exposed materials ” (it seals and forms a flexible membrane). 6: If Hull is separated enough and needs ‘New’ membrane’? ‘Cut a strip to length’, ‘Thoroughly Heat hull keel area using hot air gun ‘Required to open Polypropylene cellular composites’. slip the strip of membrane into separation areas from the bottom of Bote’ 1st. make small slits in new membrane, (only deep enough to fit new membrane full length in-between stitching) 7: inject ample amount of the adhesive between Polypropylene hull and in-between all areas of Membrane. 8: Clamp the repaired area together with screw clamps or Large Vice-grips, may need two pieces 2 x 2 or 2 x 4, to cover the area as a strong back vice. leave it on and in place all day.
      9: If the Stitching is broken in keel damaged area?, and you don’t have a ‘Palm-a-Needle and Sail Thread’. Pilot drill 1/8″ in the factory stitched hole using “smallest bit possible” (DO NOT DRILL TOO LOW on the keel) . Purchase Stainless Steel rivets SS LF-46 Rivets, and backing washers these will have to be no larger than 3/8 x 1/8 shank with large ‘rivet head’ no larger than 1/8 backing washers. Rivet each stitch hole.
      Good Luck and “Fair Winds and Following Seas” (AWSW1 Ken Shelton ) Colorado.

  4. Today I thought about my good friend Jim who drowned a couple months ago fishing out of the ever popular aluminum pram. He was alone when he leaned over to land a fish and the pram flipped. He couldn’t swim, he wasn’t wearing a PFD, and the pram deployed the anchor when it flipped and he couldn’t hang on to it long enough to push it to shore.. I have always believed that the portaboat is so much better and safer than an aluminum pram. Its faster on the water with a motor, easy to cartop, you cant sink it and its big enough to stand in, and small enough to put on a pond. The only downside is it takes time to put together. Rest in peace Jim. You use to laugh at my portaboat.and called it overkill. That pram killed you.

  5. My split is at the transom, center crease at the bottom, about a 1 inch slit opening. I just tried 3M 5200 in and out and after 8 days of curing, it separated from the plastic. Plastic was roughed up. Not sure how to fix now. Plastic welding? Stich it up with fishing line? I already tried chewing gum – no luck. Any ideas? Tried all the off the shelf adhesives.

    • I contacted west marine in (California) they recommended 3m 4000 UV fast cure. Its made for all sorts of plastics, above/below water line, flexible, UV proof. Cures after 48 hrs ( i waited 5 days).

  6. The information on the 3m 5200 is good. I used it to do the same repair after I bought a used porta boat. Float testing it in my pool slowed the leak from about 1 gal over night to a coffee cup amount. So now I will do the each corner. Again thanks for the post and good information.

  7. First of all, right on the tube of 3M 5200 sealant it states to never use alcohol because it will affect cure. Use Acetone. With all of this said I did everything as the information on the 3m 5200 tube said and waited 7 days to close boat and reopen and test. It leaked again and the 3m just separated from the hull material. This time I will use the sealant, “ProFlex” I use on my rubber roof on my motorhome. Hopefully it will seal and adhere to the hull material.

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