How waterproof are the round hatches like on the Oasis?

I was taking on a lot of water when carrying heavy loads in my Oasis. I spent an entire day making a vacuum adapter and pressure testing with soapy water and so on, but found no obvious leak. Then I realized that the weight in the rear might slightly/occasionally immerse the rear hatch by water coming up through the scuppers. That would add more weight which would lower the stern more and cause the water to leak in faster and faster. And that is what seemed to be happening if I monitored the bilge while looking through the middle hatch. Leakage started out slow, but increased to pretty rapid after the first couple of hours on the water.

I taped the scuppers shut and filled the rear deck with water. Now all of that water is inside of the hull. It took a couple of hours. Coincidence?

So I wonder if my test was reasonable. Should these hatches actually keep out all water, or would they be expected to leak slowly. If they should actually be watertight (note: there was no pressure, just a couple of inches of water sitting there) then can I just replace the rubber grommet or do I need to replace the whole hatch? I ask because the rubber grommet looks OK to me.

Thanks.

--Brian

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Brian Godfrey
kayakingforthebirds.org

My ones leaked when they had a lot of sand around the seal.

I took the seals off, cleaned them, cleaned where the seals meet the other bits. Didn't stop water ingress entirely but has reduced it 90%.

One thing I did NOT do was use a gel to help the seal. Reason being that gel would be a sand magnet.

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2014 Hobie Outback set up for rod and longline fishing

Yeah, I thought about using silicone O-ring grease, but what a dirt and sand attracter that would be.

Mine still leaks after making the ring as clean and perfect as I could. Maybe it's just time to replace it.

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Brian Godfrey
kayakingforthebirds.org

On the Oasis water will come in around that rear hatch. Clean everything up real good around the hatch, lid, and rubber seal. You can remove the rubber seal for cleaning but be careful not to stretch the seal out. I don't use any liquid or gel on the seal. While you close and latch the lid push down on it. Once the lid is closed and latched, push down on it again firmly in the center and it will likely close another sixteenth of an inch forming a good seal. The latch itself does not seem to draw the hatch fully closed.

If you search the forums there are lots of discussion on the rubber seals, their somewhat triangular cross section, and how they tend to roll on closing. Given how the roll, it is not worth bothering to try to align the seal properly since it will just roll when you close the lid.

The newer kayaks, including recent Oasis, have a different hatch design that may not have a rubber seal. I do not know how well they work and if they can be retrofitted.

One other thing to check for is any cracks in the hull right at the rudder bracket.

Peter

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2016 Hobie Oasis with Evolve v2 rudder mount, Sidekick ama kit, Mirage sail kit, Garmin echoMAP CHIRP 42dv, bilge pump
2007 Hobie Outfitter x 2 with Mirage sail kits, large rudder blades

I've been over the hull very thoroughly, but I will double check around the rudder brackets. However, my tests did show the water ingressing through the closed hatch. I usually do push the hatches down to seat them fully. Maybe they just leak no matter what. I need to figure out if I can replace them with that newer design that doesn't leak. Maybe it's time to talk to the dealer.

Thanks,

--Brian

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Brian Godfrey
kayakingforthebirds.org

The older hatch design (which is on my Oasis) has a T handle while the newer design has a ring handle. There is a retrofit kit (Hobie #71702001) but make sure you get the one with the ring handle. It seems they changed the hatch design but kept the same kit part number. Post back if you do this swap as it is on my todo list.

Peter

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2016 Hobie Oasis with Evolve v2 rudder mount, Sidekick ama kit, Mirage sail kit, Garmin echoMAP CHIRP 42dv, bilge pump
2007 Hobie Outfitter x 2 with Mirage sail kits, large rudder blades

I searched for that part number and found one on Amazon which shows the T handle. I looked at the reviews and one of the two bad reviews reads as follows:

That leads me to wonder: is the circle hatch actually better or is it worse than the T handle one; or does it fit so tight that you have to push it down even when new in order to make it seal? The latter would be good if it were true, but how do I know what is really true in this chaotic world? More research, I guess.

Oh, and here's another comment:
Mine has the 8 hole ones.

I think I'm going to try just replacing the seal first. If those are available separately.

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Brian Godfrey
kayakingforthebirds.org

The 8" O-ring is #71702021. Clean out all grit and debris before installing.

Peter

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2016 Hobie Oasis with Evolve v2 rudder mount, Sidekick ama kit, Mirage sail kit, Garmin echoMAP CHIRP 42dv, bilge pump
2007 Hobie Outfitter x 2 with Mirage sail kits, large rudder blades