quote:
I have a fixed 2 blade prop which motors forward with my Yanmar 2GM20 very well but reverses quite poorly. I am thinking of fitting a Brunton Varifold prop to reduce drag when sailing but am worried that my poor reverse will be even worse with a folder. Does anyone have experience of folding props on a 275?
John
If it helps here is my experience with both folding and feathering props.
I fitted a folding prop on my 275 and lived to regret it. On one occasion, having just tied up alongside a boat on the River Dart (in a very strong flood tide), I was asked to let him slip out. The problem was that I was stern on to the tide and facing a dead end (this was on the pontoons where the ferry leaves from). I attached mooring ropes around his boat, ready to pull in as he slipped out; with my engine running fairly hard in reverse. Unfortunately, as he left and let go the ropes to my boat, I had to go very hard in reverse - only to find that there was insufficient grip from my folding prop (incidentally I had a 19HP 2GM20 engine). I was slowly 'drifting' back into the dead end. It was only due to my own and other crews that I was lucky enough to be pulled towards the pontoon. I vowed never again to have a folding prop.
Now my experience with feathering props. 3 years ago I purchased Calypso a Parker 325, and fitted a CJR feathering prop at great expense (should have spoken to Bill first as this was another mistake). The problem with the CJR is that due to its design it comes with a very large boss (this was not apparent on the model I saw at the boat show). The consequence was that :
a) It meant the blades were shorter than optimum
b) The flow of water from the skeg onto the boss caused terrible cavitation.
After one season. I could no longer stand the noise (which was significant) and spoke to Bill. We discussed alternatives, including the KIWI, but he recommended the Max-Prop from Darglow Engineering
http://www.darglow.co.uk/html/products.htm Bill has fitted both 2 and 3 bladed Maxi-Props to a number of his boats.
Though more expensive than the Kiwi, it has something in the order of 50% more blade area (hence its name) and I was unsure how the plastic KIWI would take to being driven into hard sand when taking the ground (say at the Bembridge Rally)
I have not regretted fitting the Max-Prop.
PS - I have a
cheap CJR feathering prop in the garage if anyone wants it.
Regards
Don Harvey
Web Master
Parker 325 'Calypso'