I remember the post. I did not remember the 3-400 estimate. I would still approach the guy and offer to repair it at your cost (what the f*** does he care what your cost is?) to his satisfaction. You can have it done three times for the difference in price!
The problem with a certain type of people is, when it's somebody else's money and responsibility, the boat suddenly becomes a "yacht", as in Her Mafesty's Royal Yacht. If he insists on having his guy do the work, at an outrageous price, then he should be willing to sign a release stating that your payment of the estimated price releases you of any further obligation. If he will allow your guy to repair it, you might consider how you can involve a third party to be an impartial arbiter of the effectiveness of the repair. Or, you can just take a chance the guy is basically reasonable and tell him you will repair it to his satisfaction, have your guy do it, and hope the guy doesn't nit pick over the seagull droppings that occured while the repair was being done.
I hate having to deal with people spending other people's money. When it's their own money they get real reasonable in a hurry. Don't beat yourself up over this, it's a boat manoeuvering in close quarters. People in cars don't do any better, although you'd think they should. At the end of the day, docking is a controlled collision. I once went through a relatively normal tie-up only to have the Third Mate observe we'd punched a hole in the hull from a dockside shackle. This was on a 50,000 ton freighter. The hole was in a "wing" fuel oil tank. Imagine my relief when I discovered the tank was not pressed up, that is, slack, and no fuel leaked to the harbor! Still was a pain in the butt to pump it down, inert, and weld. But that beat a $10,000 fine and proceedings against license!
“Scientists are people who build the Brooklyn Bridge and then buy it.”
Wm. F. Buckley, Jr.