Leaky yak

I bought an 11ft native manta ray used from alder creek about 2 years ago.  I love it, but its always leaked. Used to only leak about a cup full of water each use, no real big deal.  Earlier this year it all of a sudden got way worse.  Now my hull will completely fill with water in about 3 hours. The bottom is fairly scratched up, but none that go all the way through. Ive examined the entire yak very carefully and for the life of me, i cant find where the water could possibly be gettin in. When it completely full of water, you can drag it up on land and not a drop will leak back out.  I guess mabey when im sitting in it and its on the water that counter force could be opening up the seam??  My biggest question for this posting is, does anyone have a good suggestion on how i could find this leak and fix this yak?  I really cant even use it now, but its my favorite and would hate to retire it.  Thanks again

Seal up all your hatches with plastic and duct tape, and make a area to supply high volume, low pressure air (think vacuum in reverse). 
Flip that sucker over and spray liberal amounts of Windex over the entire hull looking for bubbles.
If that doesn't show a leak, try the sides and anywhere else that would touch water when you are sitting in it.

I second that! If the Windex does not work make up a spray bottle with joy dishsoap and water and spay make it heavy. We use to check our welds when i was a welder at Northwest Natural Gas that way.

Seal up all your hatches with plastic and duct tape, and make a area to supply high volume, low pressure air (think vacuum in reverse). 
Flip that sucker over and spray liberal amounts of Windex over the entire hull looking for bubbles.
If that doesn't show a leak, try the sides and anywhere else that would touch water when you are sitting in it.

Sealing it up and spraying windex or applying soap to it is probably the best option, but if  for some reason you can't do that, dry it out real well and get it so it is raised off the ground somehow.  Then fill it with some water and see if you can find where it is leaking out.  Another way that is probably the least involved method, but not quite as effective is to get it into a dark room and shine a flashlight through the hull, either on the outside and look into the kayak, or shine the light on the inside and look on the outside of the kayak.  You should be able to see light shining through a crack that is substantial enough to fill your kayak that quickly.  This might require assistance from someone else though.  Good luck codeman!

And check your scuppers well too.

Have you tried contacting the shop you purchased it from for their advice?

-Allen

  Another way that is probably the least involved method, but not quite as effective is to get it into a dark room and shine a flashlight through the hull, either on the outside and look into the kayak, or shine the light on the inside and look on the outside of the kayak.  You should be able to see light shining through a crack that is substantial enough to fill your kayak that quickly. 

Use a drop light if you have one.  Doesn't even need to be dark in the room to see flaws in the plastic.  Have someone hold the light inside the hull while you inspect the outside.

If you find a hole, patch it.  If you find a crack, drill a hole at each end and then patch it.  I prefer using a soldering iron for hull repairs.

Dang, I just gave away the plot of the Kayak Guys column in the Nov. issue of NWS.   

-Spot-

Sealing it up and spraying windex or applying soap to it is probably the best option, but if  for some reason you can't do that, dry it out real well and get it so it is raised off the ground somehow.  Then fill it with some water and see if you can find where it is leaking out.  Another way that is probably the least involved method, but not quite as effective is to get it into a dark room and shine a flashlight through the hull, either on the outside and look into the kayak, or shine the light on the inside and look on the outside of the kayak.  You should be able to see light shining through a crack that is substantial enough to fill your kayak that quickly.  This might require assistance from someone else though.  Good luck codeman!

troublesome, but I  like this idea.   It'll give your hull a nice wash after wards. 

but if  for some reason you can't do that, dry it out real well and get it so it is raised off the ground somehow.  Then fill it with some water and see if you can find where it is leaking out. 

Also check the native watercraft web site for a contact and their warranty.

Hey thanks for all the advice guys.  I was thinking about trying the light thing. If i drop a really brite spot light style flashlight in there and seal my hatch back up, maybe that would show me something.  My dad suggested the positive air pressure too, sounds like a lot of work though, maybe a good plan B.  its wierd, i can fill fully full of water while sitting on my truck rack, and not  a drop of water will leak out anywhere.  I was thinking maybe one of my scuppers had a crack in it, from something thrown in the hull, but they appear ok.  I will contact native to find out about warranties, but it was a rental for awhile and it is pretty scratched up. 

I'm going to again suggest that you seal up your hatches/openings and supply high volume low pressure air to the inside of kayak, and spray Windex liberally to the entire surface of the hull.

I have reservations on your success finding the crack with light, if the crack won't even allow water to leak. 
With the air pressure, you have an opportunity to add outward pressure to the hull and slightly open the leaky area.
Air molecules are less restricted by surface tension than water molecules and will flow freely.  Now if you have access to enough Helium you could find defects that even air can't get through.

It's possible that the crack only opens with pressure is applied to the hull from the outside.

Check the areas where your straps or saddles contact the hull and where you sit by having someone hold the light on the outside and looking from the inside in these areas.  Also, have the light holder apply some pressure around where the beam is hitting the yak.

-Spot-