Northwater underdeck bag + poly boat

Has anyone attempted attaching the Northwater under deck bag to a poly boat?

I have an Avocet RM and would like to fit it with this bag but I’m told that the pads might not hold if I glue them - for all the known difficulties of bonding to polyethylene. The Northwater site suggests drilling holes in a poly boat and using bolts.


  1. Has anyone bonded this bag to a poly boat and is it holding?

  2. Has anyone drilled into their poly boats and attached this bag? If so - can you describe what you did and how watertight could you make it? I cringe at the thought of drilling into my new Avocet RM.

    Yesterday I saw a glass Avocet with this underdeck bag attached and the pump stored between the bag and the deck. It’s a thing of beauty.



I attatched one with Marine Goop
I attatched a Northwater underdeck bag, and two cockpit bags, in my wife’s poly boat. I tried maybe half a dozen diffent kind of adhesives, and the only one that worked was called Marine Goop. I used a lot, and I mean a lot, and rolled the boat with the cockpit facing down before starting to avoid putting any stress on the pads b/4 they dried. I also let it sit for a couple of days to make sure it was completley dried. The other adhesives bonded, but wouldn’t hold if anything was put inside of the underdeck bag, which is kind of the point. I got the Marine Goop at a Marine West.

How did you prep the area?
Exactly how did you prep the area for gluing? Also - can you actually pull on the bag and feel that it’s holding? I am trying to get a sense of how firmly it is holding with the goop? How long has the bag been in “field use” ?



A couple of years.
It’s been in for two years now, and can hold two liters of water and a first aid kit. At least that is all she has ever put into it, but the weight in it is considerable. I cleaned the area free of debris, but nothing special. The boat is a Prijion, so the plastic has a texture to it, which could have helped with the adhesion. If yours is slick, you may want to scuff it up a bit with sandpaper. I should reiterate that I used a lot of goop, maybe half a tube for all four pads, and then used a paint brush to seal around the edges so no water or debris can get in and compromise the bond. Let it dry for a couple of days before putting weight on it.

to prep for glue
wipe the area with a bit of acetone but don’t let the acetone sit pooling, just get it good and wet and wipe it down a couple of times. then scuff with some 120 grit (bit more or less) sandpaper to give the glue/goop/adhesive something to grab onto. I haven’t used the product you mentioned nor do I have the boat you’ve got but this is a good general method. On the other hand, I’ve drilled into poly hulls quite a bit and never caused any leaking. I’ve used nylon or rubber washers and silicone or marine goop on the bolts when attaching them. I usually try to make any hole do double duty… the bag on the inside, an eye bolt or rigging something on the outside, for example. If you use bolts, use locking nuts.

I’ve got one…
that has been installed in my poly boat for two seasons now. I was all hyped to install it but didn’t research long enough for the right adhesive. I drilled it baby!!! I mostly paddle fresh water and paid little attention to hardware. I put a dab of tub caulk on each screw and I’ve yet to feel a drop of moisture in the boat. I love that bag. I call it my glove compartment. It was a great place to hold my smokes and light along with a firstaid kid and a small snack or two. Alas, I gave up the evil tobacco and have more room in the bag. I too stow my pump on top of the bag. It is a great set up. I love having a more clear deck now.

Drill away
We have two boats that came from the factory with under-deck netting shelves located where you are attaching the under-deck bag (Prijon Yukon-Exp. and Riot Stealth). Both attach the netting to the bottom of the bolts for the above deck netting/bungees. I would also test the Marine Goop on your boat- the Prijon plastic seems to be different than other manufacturers. BTW: Marine Goop can be purchased at Home Depot and I have been told that the only difference between the Marine and not marine is a UV inhibitor. Regardless I think you should drill and bolt. I use stainless steel bolts in either ¾” or 1” depending on the fitting. 10/24 seems to match 3/16” bit and is the size that all the fittings use (and all the pop rivets I have drilled out and replaced). As was suggested I use stop nuts with nylon inserts and both stainless and rubber washers (although sometimes I skip the rubber on above deck fittings). I actually do so much that I bought all the stainless by the box instead of one at a time. I think the most important thing is to make sure the bolt is sized correctly and engages the nylon on the stop nut without protruding past the stop nut.

Drilling 3/16” holes is not scary- drilling 1” holes for drain plugs is scary- hard to those mistakes!

Since the bag hangs lower than the netting, will it interfere with your feet?

Never thought about netting! Makes sense. the bag in question is apparently not waterproof so not sure I see any real advantage over netting. You could make this thing as long as your arm could reach as long as it doesn’t interfere with your leg positions. I also thought about netting or some sort of bag arrangement on the sides of the kayak just in front of the seat pan for sponges and a lightweight rain poncho?

Look in the bike shop
I wanted something for our other boats, I found a small net made of thin bungee in the bike department of REI. It is designed to secure things to a bicycle rear carrier. I found a slightly larger netting at walmart near the bungee cords that would serve the same purpose on a motorcycle.

bungee netting!
even better! Out of the way when you don’t use it!

Bag is great
completely out of the way - takes up wasted space. I only noticed mine getting in the first couple times. Never think about or notice it entering/exiting now.

Netting would work - but not as well IMO. Would limit capacity and security I’d think. Bag rides between shins, between knees and feet, where there’s a lot of room for the bag to hang.

Sunday I had cell phone in dry bag, VHF, A couple snack bars, a big apple, and my mask in there and it wasn’t half full. I’ve had that, plus my lights (3) and 2 20oz sport bottles in it. I’ve put a 2 L hydration pack in it.

Net may hold stuff OK depending on what you want to hold - but a zippered bag makes sure it stays there. Pump fits in above the bag too - and doesn’t take up bag or net space.


good points.
did you get my e-mail about the pfd and skirt?

Underdeck tube

Take a look at this under deck tube from kajaksport.

I dont know if it can be glued on to a polyboat.

under deck
tube…has no commentary on the page…hard to tell what it would do, dimensions, etc. Is it waterproof? If so then it would be very interesting.

Maybe a large pvc pipe sealed on one end and screw top on the front side?


another view and some text

Still not much text.

I didn’t have much luck

– Last Updated: Aug-24-05 11:41 AM EST –

sticking the pads to my fiberglass boat either. So I gave up on them and threaded the buckles onto 1/8 x 1/2 inch aluminum bar stock (get at HD or Lowes) bent to conform to the underside of the hull. That is stuck on with 3M double-sided foam tape and then aluminum duct tape over that for good measure. It's very secure.


Mike - in the second picture, how did you secure the pump to the underside of the deck?



Short length of PVC plumbing pipe
I had downstairs, probably 2" size. I epoxied that up there soon after I got the boat and it seems to be holding fine, unlike my attempts making the underdeck bag pads stick later on.

The underdeck bag came much later and as noted above it would do a fine job holding up the pump all by itself, so I wouldn’t need the tube now. But, I’m not going to risk cracking the boat trying to detach it.