I’ve just finished painting my propeller. It does seem a shame to cover up all that lovely bronze, but I think it may be getting some really hard use this year. The wind in Scoresby Sund can often be very light. If there is a lot of drifting ice around then it can be very hard to steer a clear path whilst under sail, so motoring will often be the way forward. Johnston and Loftus Boatbuilders had the propeller specially cast in nickel aluminium bronze by Clements. This is a very resilient material both strength wise and for resistance to corrosion. The blade profile is quite chunky which I am hoping will be helpful if it hits chunks of hard ice.
The last couple of years I have used anhydrous lanolin to guard against weed growth. It seems rather implausible, but it does actually work. If fact, this year I really struggled to get the lanolin off. I tried very hot water and washing up liquid with a scouring pad all to no avail. You could feel the slight stickiness after all my hard work, if anything I had just worked it in and improved its covering power. It eventually succumbed to acetone then aggressive sanding with 80 grit sandpaper.
The lanolin had protected the prop against nearly all the weed growth but this year I want it to be spotless. I normally use a collar anode but the wrong one arrived and the replacement one was delivered a day after launching – typical! I could have dived to fit it, but I find collar anodes need a dab of Sikaflex over the bolts or the zinc erodes around the fixings and the whole shebang comes loose. I eventually decided to go without an anode for the 2021 season. It did result in a few minor surface spots of pink showing some dezincification, but all minor stuff.
This year the prop has had a coat of Seajet Propellor Primer and two coats of Emperor Antifouling. I will fit the anode before the launch.
The great thing about long keeled yachts is that they very rarely get their props wrapped up with ropes. You could happily sail or motor over a line and it would just pop up behind you, there is nothing at all to snag it.
Being a small yacht is handy because I can actually change the prop under water. I had to do that in Guadeloupe in 1997 when the key in the keyway failed after reversing hard to get off a sandbank. Don’t ask why I was trying to get off a sandbank, but if they want to move the point when they change the direction of buoyage it would be handy to note it on the latest chart!
Talking about keyways, it is best to first fit your prop without the keyway. Ensure everything is spotlessly clean and whack the prop up the shaft and mark the furthermost point with some crisp masking tape. When you refit with the key in the slot make sure the prop reaches the tape mark exactly otherwise it could be “keybound”.
The preferred prop size according to Johnson and Loftus calculations was 14” x 7” but it wasn’t possible to get one made in Nickel Aluminium Bronze which was my preferred material, so we eventually went for 14” diameter with an 8” Pitch. It seems to work well – the little boat feels like a tug!
It was made by Clements
The shaft is 25 mm
The engine is a Beta 16 hp