The RYA's former Yachtmaster chief examiner, James Stevens answers your questions of seamanship. This month, without getting into the water could you clear a line wrapped around the propeller?
Eric and Joyce are on their way back from their annual cruise on board Layline, their 32ft (9.7m) Westerly Fulmar.
The Fulmar is fin keeled with a hanging rudder.
The wind has dropped so they are motoring along the coast about a mile offshore.
The tidal stream is currently foul, about 0.5 knots, but in an hour or so it will change in their favour.
It’s a lovely sunny day, Joyce is in the cockpit doing the crossword, back against the bulkhead facing aft. Eric is on watch but has engaged the autopilot.
Eric has a glance around, it all looks clear, and goes down to the chart table to check the navigation.
While he is below there is a loud clunking and the engine grinds to a halt. Eric’s heart sinks, it sounds as if there is a rope around the propeller.
Worse, when he comes on deck the yacht seems to be moored to the bottom by the prop.
Eric and Joyce, although experienced sailors, are in their 60s and are not particularly strong swimmers.
They do not have goggles and wetsuits on board.
They are both very reluctant to go over the side, particularly with a tidal stream running.
Do they call for help, or is there anything they can do to extract themselves from this predicament?
Their first problem is to try to detach themselves from the bottom.
Sometimes it is possible to unwind ropes by manually turning the shaft from inside the yacht, though in this situation, where there is probably a buoy on the end of the line jammed against the hull, it could be difficult.
If they can manage to cut the line and free the yacht they will take the strain off the shaft, reducing the possibility of damage to the boat and allowing them to anchor and wait for wind to take them home.
Sometimes it is possible to reach the prop from the aft boarding ladder with a serrated knife lashed to the boathook.
However, it’s certainly not easy because it’s pretty much all done by feel.
Their best chance is to go up to the bow, preferably at slack water with a weighted line and, each holding an end, pass it under the boat, under the keel and the rudder and hopefully pull a bight of the pot line up to the surface where they can cut it.
If there is no wind they will need the anchor ready to drop.
Holding the end of the pot line, it is worth trying again to unwind the line by rotating the shaft.
At least they are now free to move and can either sail if the breeze fills in or call for a tow.
There are occasions when this problem could put the yacht in grave danger when close to the shore off a dangerous headland.
A mayday call would then be justified, but in most situations, once the yacht is free from the bottom, sailing or organising a tow gets you to within range of a marina or a boatyard with a launch.