Volvo folding props.

[potentillaCO32]

Looking for a bit of propeller advice.

I've got a 2.5 ish ton mgc27 with a 9 hp volvo 2001 from 1988 with an original volvo folding prop. The engine runs like a sewing machine and was reconditioned a few years ago.

The boat is underpowered under engine just about touching 5 knots when clean but struggling against wind or tide.

Ideally, i would replace the volvo with a larger Beta but cant justify the cost. It would be easier to trade up boats than spend 5-7k on an engine.

However, i cant help but think that the lack of umph is down to the folding prop. It is a flat rectangular two bladed one and if you look at the latest volvo folding props and other feathering designs they look a lot more hydrodynamic (if that is a word).

So I have two questions for the wise and kind. 1) is a more modern folding/feathering prop likely to make any noticeable difference to the thrust compared to the 1980s volvo folding one and 2) looking at the fyb website the nicely shaped blades of the latest volvo folding prop look to fit into an identical hub with the same cog and pin arrangement as mine. So could i just buy the latest blades as a cheaper way of progessing?

 

[Tranona]

Simple answer is yes, the later props are likely to be better, but not sure the new blades will fit the old hub. Maybe ask FYB. You should be able to get around 5.7knots at maximum revs with the right size prop which is probably a 13*7. Do you know how much a pair of blades cost? Thy will be les than a new Volvo prop, but you may find that changing to a better prop overall is a better bet. The FlexoFold is probably the best performing 2 blade folder and is cheaper than a Volvo, but unlikely to be as cheap as new blades.

The reality is though that you need more power to achieve hull speed (which is over 6 knots) so any improvement with better prop/blades is likely to be marginal. A 3 blade fixed prop will get the most out of the meagre power but guess the loss in performance under sail would rule this out, and a 3 blade folder or featherer would be a very expensive alternative.