Mossberg sells a line throwing adapter for their 500/590 series shotguns. Remington doesn't list any on the website but they do sell shotties specifically for marine environments so a call to the service dept may yeild results. I know you were wanting to improvise but I'm leery of sticking anything down the bore of a gun that I'm about to shoot (a ball down a muzzle loader being an obvious exception). Any online instructions or Paladin Press type books should be taken with a liberal dose of salt.

A cheaper and more compact alternative that could be easily duplicated at home can be found here www.ezhang.com

Ed

Very interesting feedback.
Thanks much for the insight.

An interesting alternative. However, at $695.00 a copy, it is way over priced.

www.reveresupply.com/mcmurdo/linethrower.html

Hmm... An interesting image comes to mind, a kayak with a gun rack. <img src="images/graemlins/wink.gif" alt="" />

Depending where you're kayaking, a slingshot and paracord with a rock or similar weight tied to one end might be easier and safer. PlLus those tools have the advantage of multiple uses under different emergency scenarios.

Planning for vs (X) improvising
Hmmmmmmm

Our team uses the Lyle (Bridger) line gun. A brief history of the Lyle (Bridger) line gun can be seen here: http://www.cannon-mania.com/lyleguns.htm
The model we have can be seen at these two web sites:
http://www.lhrservices.com/search_and_rescue/line_gun_kit.htm and
http://www.rocknrescue.com/acatalog/Line_Throwing.html

We did have to get some type of exemption/license from BTF, since the barrel is shortened.

We are also in the process of buying the Sherril Big Shot also shown on the second web page. Pete

The broom handles I have don't fit down the cylinder bore barrell of my Remington 870, so my testing has not happened. the only thing I had thin enough was some copper pipe, and that's really not a great idea - a hollow pipe.

yeah, but the line thrower attachment from Mossburg costs 645 and that doesn't include the shotgun.....

Interesting reading.
I would be interested in learning about the training you go through with these.

Perhaps a piece of PVC. If it is the right diameter, it might be a bit more convenient. Obviously will need an end cap, most likely on the end outside the barrel.
Still sounds a bit dangerous, but might work. Don't think that I would want to make a habit out of using one, could work as a last resort.