With Peter on watch, at 0130 he decided to start the engine to maintain our pace as the wind dropped away. He had forgotten that we sail with the engine in gear astern to feather the propeller and when he started the engine in gear there was a loud banging noise which propelled me out of bed like lightning. Starting the engine in gear should not be a problem, it is just better practice to start in neutral but, somehow this had caused a serious issue. The engine started and ran smoothly in neutral but banged loudly in astern and slightly less loudly in forward gear. What could be wrong? Everything was OK when the engine was switched off some time ago, so the propeller, bearings and gearbox should still be OK. We had checked the oil level in the gearbox the day before, had we done something? A look in the engine bay offered no explanation so we had to think logically about what could possibly be going on.
At this stage, contingencies run through oneās mind. What if we canāt use the engine again, where should we head with calms expected tomorrow, should I don the wet suit and have a look underneath ā would I be able to do anything about whatever I might discover?
We had been experiencing a clicking which we had attributed to the rope cutter but with the spacing shims checked in Antigua and found to be within tolerance, we had assumed it was something to do with the fixed blade spring. Raising Barry to join the discussion, we tried to turn the prop shaft manually. It would turn about 15 degrees before coming up against a stop and this would accord with the distance between the fixed and rotating blades of the Ambassador rope cutter if they were in conflict. When I bought the yacht, the fixed blade was missing so there had clearly been an issue in the past and Peter had experienced a problem only last year with the Ambassador on his Vancouver. Barry brings an enormous amount of experience to the picture and he has also witnessed problems with this type of installation. We concluded that the blades of the rope cutter had become misaligned and in conflict which is probably what had happened before. In that the fixed blade had clearly āpingedā off before, we should be able to break it again and we all agreed that we should try to deliberately break the blade by nudging the engine in and out of gear, forwards and astern until the blade broke. Barry manned the gear lever while I watched the shaft through the access panel over the stuffing box. After only a few cycles which slightly deflected the shaft, the blade must have broken as the shaft started rotating silently and, thankfully, concentrically. Phew, what a result!
The adrenaline levels made immediate sleep unlikely for Barry and Peter it being, by now, time for my watch so we chewed the fat for a while and Barry commented that he didnāt like the Ambassador rope cutter and that fishing boats all use a blade type which doesnāt have āspursā that can foul so that is another job on the list ā change to a maintenance free blade type when lifted in the winter.
We will have logged over 10,000 miles since leaving the UK just over a year ago and this is more than some yachts do in a lifetime and it must just have been too much for the popular but clearly flawed Ambassador.
In the meantime, I hope we donāt encounter any discarded rope to foul the prop!
Hello Hejira!
This is S135 Istana calling!
Unless I am mistaken Hejira, like Istana has a Max-prop. This being the case it is not necessary to keep the engine in reverse gear when sailing. To feather the prop all that is needed is to give the engine a ‘little touch’ of reverse and then back into neutral before pressing the stop button and the prop will feather. (Hence no danger of not starting in neutral!) If in doubt check the max-prop manual.
Another point: if you are still getting a knocking noise from the engine, check that your engine mounts are secure. In my experience engines need lifting every 10 – 12 years and the engine mounts replaced.
Love and best wishes from your elder sister
John, just picked this up with the terrestrial mobile signal picked up off the NW tip of France. I used to have a Vari-Prop and changed it a couple of years ago for the Brunton’s Autoprop which is excellent when you get used to it and is very much more efficient when motor sailing. The full explanation is in the following blog but suffice it to say that the problem is overcome and I will be changing the rope cutter for a blade type when next lifted. Now keepiing an extra vigilant look out for pots!