I was very lucky to have found a used but solid Necky Alsek poly-hulled, sea-kayak for a really good price at this time of year (April).
It's my 1st sea-kayak although I've had a Sevylor inflatable for a year and used it on some fairly long-distance lake trips here in southern BC.
The Alsek's front hatch is clearly a very solid design that I think would remain sealed even if the hull was submerged, but the rear-hatch, neoprene gasket is missing. The boat came with just the plastic top part of the rear hatch and if submerged, it would take on water.
My question is this: How safe is it without the rear hatch seal? The front compartment, although not that large, would keep the boat above water if push came to shove, but if the rear hatch and cockpit are likely to flood on the water, I'll wait till I get a rear-gasket and skirt.
I have to wait till the end of the month before I can get a skirt and seal though, and would like to take it out now.
Also, how much freeboard is there likely to be --- I'm 210 pounds.

Oh yeah, I forgot to ask --- the hull pretty scratched and I was wondering if there was some way to restore the smoothness of a poly hull?

You can very carefully scrape the little plastic boogers off with a razor, or very sharp knife. Then, what I do is scrub the hull with hot soapy water to remove any wax, or vinyl protectant and coat the bottom with water based polyurethane. Varithane makes an outdoor version and I use the crystal clear gloss. It brings back the luster to the finish and I even believe it reduces friction.

As to paddling with no seal on your rear compartment I'd say wait. A kayak that has both a flooded cockpit and after compartment is really difficult (if not impossible) to self rescue as they float vertically in the water.

That said, if you decide you have to take the chance at least completely fill your rear compartment with flotation: Float bags, closed cell foam, extra lifejackets, loosely filled dry bags, poly bottles, empty bladders from boxed wine etc. The hatch cover will keep them in place and at least you'll float horzontally in the water at a rescueable freeboard.

I took it out for a maiden voyage off Blackie Spit --- it performed admirably.

It's so much faster than the inflatable, it's mind boggling.

I got a $30 can of water-based poly and applied it to the hull. It looks like it's working well -- the surface looks so much smoother now. I'll put more coats on.

So far, I'd have to say the water-based polyurethane is just the ticket.

Thanks, guys.

http://picasaweb.google.com/tomfromvan/Maiden_Voyage/

Is the link to where I've put pictures of today's outing.

I got a $30 can of water-based polyurethane deck varnish and have put several coats on the hull (after removing the boogers with an exacto knife).

And it looks fantastic --- as new again. Very smooth and glassy-surface.

I'm finding that I like polyurethane as a hull material because t's re-formable with heat, and takes an excellent finish. I bet it''l be a little easier to paddle now, too.
Woohoo!

I could be wrong, but I think the material your boat is made of is polyethylene.

You might want to invest in some different kind of carriers so you can transport the kayak on its edge, or at least on its bottom. Also, I hope you don't store it upside down out in the sun.

I've never heard of a Necky Alsek, but from the look of that hull, you don't have to worry much about it being tippy.

I would opt for storing and transporting the boat on its edge. The problem with transporting upside down is that you must cinch the boat down and straps,or rope might deform the hull, especially on hot sunny days. For most kayaks, the strongest, most ridgid cross section is on edge.

I ended up having to peel the water based poly coating off because it was not durable enough and was making thousands of little flakes. On it's first contact with sand/gravel it started to peel and flake off. I read about how harmfull flakes of plastic are to ocean critters like turtles, for instance, who die when they ingest plastic bags thinking they are jellyfish. The flakes are too small to kill large turtles, but I hate to think I'm the cause of a thousand small sea creatures having their digestive tracts jammed up by non-soluable flakes of that stuff so I spent a long afternoon scraping it off. Maybe it was the wrong type or smt, and please don't interperet this as some kind of grouch --- I know it was just a suggestion intended to be helpfull and hey, it was certainly worth a shot, but if anybody else is thinking about trying it, I would strongly advise against it. It's simply not durable enough.

Hello Guys:

Found this forum via google. I now this thread is about 2 years old, but I too have a similar problem. Bought a second hand Ocean Kayak Malibu Two Tandem SOT made out of "linear polythene". There are lots of scratches and even some minor gouges. I need some sort of simple coating solution for the hull. I'm from Trinidad and there are many of the more sophisticated technical solutions available down here. I need some advice.

The polyurethane that I coated my Loon with is still in place. Not one square centimeter has come off.

Maybe there is a difference in polyethylene surfaces, but I doubt it. I did not sand the surface, nor use anything other than soap and water and a scrub brush to clean the surface before I applied the urethane.

The difference might be that I never drag my boats on sand, rocks, or anything else. Some might think this is being fanatical. So be it. Someday I may not be able to pick my boats up anymore--then maybe I'll use a dolly, or get lighter boats.

I still believe that clear water-based outdoor polyurethane is a quick and easy way to refurbish the surface of polyethylene plastic. I would suggest that some judicious smoothing out of the surface with a very sharp knife, or razor blade might be good. The temperature should be above 60 degrees when the urethane is applied. It dries very fast, but it should probably be given a few hours before using the boat.

If you're worried about turtles, maybe there's some other procedure. If I thought that polyurethane would be harmfull to sea lions, I'd feed it directly to them. I hate them buggers.

Happy to help out here.
I'm the marketing director for necky.

feel free to ask any question you'd like and I'll make sure we get you a response asap.

It sounds like you have a plastic, not composite, kayak. flaking is almost unheard of but since this is an older model, I can't say for certain that this is not due to poor molding at the time.

Scratches have little to no perceivable impact on the boats kayaking ability. It is primarily a cosmetic concern. If you have 'danglers' or bits of plastic near or around the scratches - they can be removed with a knife.

Hope this helps. But please let me know if there is more i can answer for you.

Sincerely,
Chris Heffernan

Okay Chris, here's the question: Is there a method by which a polyethylene surface can be smoothed with the use of lighter fluid and flame? I realize this could be a touchy kind of repair, but I was told by a fellow one time who claimed to work in a plant that builds plastic kayaks that they use that method to fix minor flaws in boats that get slightly damaged in handling. He said they pour a small amount of lighter fluid onto the damaged area and light it. Apparently the plastic would smooth out as it melts and the flame could be quicly blown out.

I'm not likely to try anything like that, but I have wondered if the guy was telling the truth, or if he was just full of crap.

Chris,
Thanks for checking in on this subject. It's always nice to have the manufacturers support. Hopefully the group takes advantage of your offer to share your knowledge.

I have a Necky Santa Cruze (w/ skeg) bought new as a blem primarily for river use. Fabulous boat, hard chines, lots of rocker, nothing else like it. It has had close encounters with rocks and gravel. I took a palm sander to the bottom, as well as to the blem aspects of the top, worked like a charm. I then used 303 Protectant, which destroys friction, has super UV protection, and takes longer for me to type about than to put on. That stuff is magic. Chris, if you're listening, I have 3 friends who would buy a Santa Cruze if they could...