Yes. In our boat we'd have to tie off the shaft with the damaged prop, strut (or damaged shaft itself) because we can't let a shaft freewheel with its associated engine not running.
We've had to finish a run on one engine four times since buying the boat in 1998. None of them were as the result of external damage, however. Three times were due to cooling problems external to the engine, and the fourth time was my fault for letting an engine get a*slug of air during a fuel transfer. In all cases we tied off the shaft of the shut-down engine and finished the trip on the other engine.
Since you seem interested, as an illustration of what can happen up here, friends had their twin-engine, 40-something foot, steel hull-wood topsides*deFever named Sea Beaver up in Big Bay in the late 90s. Big Bay is a (now) former resort on an island about 230 miles north of Seattle. This area with its hundreds of islands, narrow channels, and large tidal ranges (12-17 feet or more) is notorious for its swirling currents, upwellings, and rapids.
As they were leaving Big Bay and negotiating a nearby rapids at the end of slack water, an upwelling barfed up a huge saw log and jammed it between one of the prop shafts and the hull in such a way that it also jammed the rudders. So Bob not only lost thrust on one side of the boat, he couldn't steer. The current was moving the Sea Beaver slowly toward the rocky shoreline on one side of the fairly narrow passage.** Bob, a very experienced boater and pilot who was the picture of calm in a crisis tried to free the log with*the*pike pole they carried on board but it was too wedged in. He and his wife then lowered their dinghy, a Boston Whaler suspended in davits off the transom (a good illustration of why keeping a dinghy stowed on a cabin top or boat deck is, in my opinion, a very*Bad Idea).
So they had the Whaler in the water in moments and got a line to it and Bob tried to pull the*Sea Beaver*out of danger. Even though the Whaler had a decent size motor on it all he could do was hold the*Sea Beaver*stationary--- he couldn't make any progress away from the shoreline. And the current was building. When it became apparent that the boat was going to go into the rocks no matter what, he told his wife to prepare to abandon the boat. As she was preparing to do so and as the Sea Beaver was carried slowly closer to the rocks, the log suddenly popped free on its own.
Bob quickly returned to the boat, found the rudders were free, and with the remaining engine powered the Sea Beaver into open water. It took only moments to determine that the running gear on the one side had been damaged enough to preclude using it. So they completed the run back to Seattle and Lake Washington on the other engine.* I don't remember how long it took them-- three or four days I think.
And that boys and*girls,*is boating in the Pacific Northwest.*
It's also one of the*reasons my wife and I prefer a twin engine boat over a single.* While one can speculate forever, the saw log came up into the Sea Beaver'srunning gear from below.* Had the boat been single engine, there is no guarantee that the log could not have launched up into the prop and rudder and taken them out of commission on the way by.
When it comes to stuff in the water, it's a crap shoot.* The only defense you have is a really good pair of eyes and the ability to keep your attention on the water in front of you.** And for deadheads and incidents like what happened to Bob, even that can be not enough.
-- Edited by Marin on Saturday 12th of February 2011 12:10:21 AM