You don't need a school. I train working dogs. It should be relatively easy.
1) Start by training your dogs to go on command. Every time they go use a command. We use "last pee" (yeah, covers poop too). Say it EVERY time they go. Then once they associate it, basically start reversing it. First you're just associating the command, then you're using it for cause and effect.
2) There are two fairly simple ways that I know of to get a dog to go in a specific spot.
a) Spread newspaper over your entire cockpit. Then as the dog learns to use the newspaper, start removing most of it until you've got a little square in the cockpit. Use the for a while, and then just remove that last little square. Usually they'll stick to that spot.
b) if they usually are dogs that go on grass, you might be able to just get a bit of turf and do roughly the same but without covering the whole deck. That's what I did/do with dogs for my boat.
Combine the two and I just say, "last pee" and my dogs go over to the spot and go....