One of the over winter projects was tackling the vibration we’d noticed from the propellor last summer. It had got bad enough that we’d had a diver check that it wasn’t fouled.
We have a Max Prop. It’s a clever feathering prop design, where the pitch can be adjusted – and even be different ahead and astern. It can also be easily adjusted between left and right handed rotation. When under sail the prop will automatically feather to a very low drag configuration, and the pitch is wound back on when the engine is put in gear.
Once we got Trouper out of the water it was obvious that the Max Prop was badly worn, The prop was original and dated from 1989, and had been serviced twice before, once by me. That had cost about £600 some ten years ago so I wasn’t looking forward to the bill. Worse still the advice at the time had been that it could be done a third time but that was likely to be a shorter lived repair.
Armed with this knowledge I got in touch with Max Prop, who’d been very helpful with new settings for the prop when we replaced the engine, a couple of years ago. They were really helpful and offered a part exchange replacement for their new model, that features simpler adjustment, for ‘only’ €1300 plus UK import duties. A new one retails for several times this.
So just before Christmas I got the old one off – which proved to be quite a job after I rounded a hex socket on one of the bolts and had to drill it out. It took both a bearing puller and a blow lamp to get the core of the prop that has a taper and keyway in it to match the taper and key on the shaft off. It was duly packaged off and couriered to Max Prop in Italy before we went to Canada for five weeks. It never got there, and it appears that it was lost in Italian customs. At this point I was a bit worried that without the old one I was in for the price of a new one – and of course the carrier insurance proved to be worthless as you had to show the purchase invoice for the lost item, not it’s replacement.
Max Prop however rose to the occasion and agreed to honour the deal – despite not receiving the 14kg of scrap bronze in exchange. They shipped a new prop with a taper and thread to the specification of the original drawings. Beyond a little adjustment of the key it fitted properly and was on in time for the boat to be launched.
Once afloat I recommissioned the engine (after sorting out some other stuff) and discovered on putting it in gear on the berth that we went astern when ahead was engaged and astern when ahead was engaged, We have a conventional right handed rotation, but I suspected that we’d been shipped a prop set for left handed rotation. A quick google established that on the max prop easy that we now had it was a simple adjustment to change from one to another. I got in touch with Max Prop and they agreed that this was the likely cause, so I booked a lift for the following Friday where the boat would be held out of the water whilst I adjusted the prop.
The video above shows what we found, and the general operation of the max prop, together with the evidence that I really need to try harder at antifouling the prop.
Unfortunately what this also shows all too clearly is that the prop is set for right handed rotation. The dot on the inner ring is clearly aligned with the R stamped into the outer ring. It was at this point that I realised that the Italian’s take their May day bank holiday on the Friday, not the Monday as we do. I coulnd’t get hold of them at all. So we put the boat into the yard ashore and I took the prop off and home, giving up on any idea of going out on the boat for the Bank holiday.
On the Monday Max Prop got in touch and we were reluctantly getting ready to ship it back to them in Italy – all very conscious of the lost prop last time and the likely 2 week delay at best. As a last measure we all got on a whatsApp video call and they examined the prop whilst asking me to move the blade positions. They spotted a problem – the inner sleeve appeared to be out by one notch. After a trip to screwfix for me to buy some circlip pliers (mine were all at the boat yard, I don’t commonly need them in London) it was a fairly quick and easy job fix it with them showing me what to do using another prop on their bench in Italy.
Then it was just the matter of another Friday off work, and another crane lift to put her back in the water and test that all was working as it should. Max prop had been so good around the lost parts at the start of the year that I decided that I’d not try to recover the cost of the lifts – it seemed as though one good deed deserved another.
Thankfully I could drive her back onto her berth without a problem: it was fixed, and will hopefully now last another 35 years or more.
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