I can't say for sure that you won't find anything on bar shot (aka double-headed shot) but to get a good idea of the effect you would need to have as a target the masts and rigging of a sailing ship, and that gets very expensive. Double-headed shot was made to catch the rigging and sails if not masts, and rip and cut them attempting to disable the enemy ship's mobility, after which the battle would conclude fairly quickly.
Also, I really haven't seen anyone reproduce bar shot intended to be fired, although with wide availability of steel in all shapes and sizes it should not be too terribly hard these days.
If you find someone with about $10K minimum to set up a test, I'll provide the artillery, crews, and range if it can be concluded before Labor Day when I get very busy again.
Here's our little demonstration of canister ammo fired from an antique swivel gun, which you may take to be a small-scale demo of grapeshot fired from a larger gun. We did another video a couple of years back where we fired bolts, chains, etc. from a 3" gun to see what it would do to some pallets. That's on YT also, but I'd have to search for the right one out of our 283 videos there.
Can't seem to get the li'l TV screen to show up but here's the link to the canister one:
http://www.youtube.com/watch?v=xsVaT694wI8