NorthWest Kayak Anglers

Kayak Fishing => Drillin' & Cuttin' => Topic started by: demonick on May 26, 2014, 12:54:17 PM

Title: Hobie hatch O-ring replacements.
Post by: demonick on May 26, 2014, 12:54:17 PM

The stock Hobie hatch o-rings often become a problem.  In cross-section they are shaped like a square block with a stacked triangle. The square base fits into the groove on the hatch cover and the peak on the triangle is supposed to create the seal.  Because of their weird shape they eventually stretch and twist.

Over the winter I replaced my stock o-rings with these (BN70-445, 8" ID x 8-1/2" OD x 1/4" W):

http://www.oringsusa.com/catalog/product_info.php?products_id=104005546

They are only $0.91 a piece, but the $7.50 shipping will make you cringe.  Order 4 or 6 or 8 or 10 and share them with your friends to lower the unit cost as the shipping is constant.  If you only buy 2 the total cost with shipping is about half the cost of new Hobie o-rings without shipping.  At first I tried the 3/16" wide versions (bought 10) but they slipped into the hatch groove and never touched the hatch ring - too small.

Ideally these could be a little softer, but I couldn't find them in BN60 plastic (the lower the number the softer the "Buna N" plastic (co-polymer butadiene and acrylonitrile)).  Install them warm.  You may need to push them into the hatch lid groove.  Grease them up with a silicone grease and close the hatch.  They might be real tight at first, but they will take a set, and the warmer they are the softer.  I've been using them for a while and they have loosened up.  They seem to seal well.

Googling "o ring BN 60 -445" gets hits.

BN70s.  Not sure how the total price compares.

http://www.grainger.com/product/O-Ring-1KPL6?functionCode=P2IDP2PCP

http://www.metrogasket.com/o-rings/prices/o-ring_prices.htm

Title: Re: Hobie hatch O-ring replacements.
Post by: momo fish on February 22, 2015, 10:27:26 PM

Seems like a great solution to a common issue. Have they held the test of time ?

Title: Re: Hobie hatch O-ring replacements.
Post by: sherminator on February 23, 2015, 10:15:46 AM

I have found that using silicone spray on the hatch has greatly improved the life of the O-rings. Whenever the hatch seems a little harder to close, I spray the O-ring, and also the latch handle where it goes through the hatch. I keep a can of the spray in my truck. Also wipe away any sand or other debris when you see it.

Title: Re: Hobie hatch O-ring replacements.
Post by: demonick on February 23, 2015, 04:48:06 PM

They have held up. I still lube the round o-rings with a silicone spray, and keep them clean of sand and debris. The problem with the stock o-rings is Hobie got too cute. The asymmetrical cross-section makes them twist in the channel and the twist makes them leak.

Title: Re: Hobie hatch O-ring replacements.
Post by: Kyle M on February 23, 2015, 05:23:25 PM

You can also go to a Granger store to avoid shipping costs.  Check google maps.

Title: Re: Hobie hatch O-ring replacements.
Post by: Nangusdog on February 23, 2015, 05:34:28 PM

I bought a 10-pack of these to try but they're just a bit too big and stiff (I know what you're thinking)...my hatches won't close properly with them.. even with copious silicone lube. 
I ended up going back to my Hobie o-rings but keep them clean and well lubed with silicone.

Title: Re: Hobie hatch O-ring replacements.
Post by: polyangler on February 23, 2015, 08:33:09 PM

Quote from: Nangusdog on February 23, 2015, 05:34:28 PM

I bought a 10-pack of these to try but they're just a bit too big and stiff (I know what you're thinking)...my hatches won't close properly with them.. even with copious silicone lube. 
I ended up going back to my Hobie o-rings but keep them clean and well lubed with silicone.

Are we still talking seals, cause all this talk of stiffies and lube is quasi exciting

Title: Re: Hobie hatch O-ring replacements.
Post by: Skidplate on February 23, 2015, 08:55:02 PM

I bet the engineer that designed this still holds that his design is flawless and the fault lies in the buna being outside of stated spec. (If the seal did stay locked in that channel, it would theoretically work.)
BTW I'm more of a McMaster fanboy. Grainger seems to regularly send the wrong stuff, plus they usually cost more. This Oring appears to be no exception. Fastenal may also be worth checking out for these. Many times they'll buy them in bulk and just sell you the single.

Title: Re: Hobie hatch O-ring replacements.
Post by: craig on February 24, 2015, 10:05:45 AM

Quote from: polyangler on February 23, 2015, 08:33:09 PM

Quote from: Nangusdog on February 23, 2015, 05:34:28 PM

I bought a 10-pack of these to try but they're just a bit too big and stiff (I know what you're thinking)...my hatches won't close properly with them.. even with copious silicone lube. 
I ended up going back to my Hobie o-rings but keep them clean and well lubed with silicone.

Are we still talking seals, cause all this talk of stiffies and lube is quasi exciting

Did someone mention lube??Buy in bulk and save money. Gotta love Amazon.
http://www.amazon.com/Passion-Natural-Water-Based-Lubricant-Gallon/dp/B005MR3IVO
(http://ecx.images-amazon.com/images/I/41W0k6dUTUL.jpg)