Does anyone have experience of these composition blade, variable pitch props in use on 40 -70 Hp outboards? I have recently suffered damage to my standard prop and wondered if these are a practical alternative for medium size motors. We have a wide range of weight conditions on our small RIB so the ability to quickly change the pitch of the baldes appears quite attractive. When used as a support boat we are often at risk from shallow water, rocks, etc. and the ability to quickly change a damaged blade could save a whole day's coaching session ( coaches are too expensive to have standing around idle)
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Mark
** Kids in Toppers? ... Like herding Cats!.. But HARDER!!** :-))
Tried a piranah composite prop on my suzuki 85. Lost power although the rev speed ratio was the same, it was like putting an extra diver on board. I ended up going back to the aluminium one. I can only assume the blades were flexing.
I used a propulse prop for a 1300 mile trip down the mississippi. They are great as long as you don't care too much about top end speed.The pitch is variable by 200 rpm adjustments. If you hit something the blades just sheer off. Usually you lose only two, enough to get you to shore and install new blades. Here in the states the blades are only about 20 dollars. You need to take the prop off and unscrew 4 allen wrench bolts to replace and adjust the pitch of the prop. Its possible out on the water but I wouldn't recommend it. For your purposes I think it would be perfect.
Used a propulse on my 40hp for a while. Was reasonably satisfied until it came to replacing all 4 blades at once. Ended up OEM alu props at a cheaper cost.
+ points Blades seemed to sharpen over time and didn't suffer the dinks that appear on alu props.
Saved weight and space in the boat by carrying 2 spare blades rather than a full spare prop.
2 blades proved sufficient to get back ashore when required (and gave a top speed 3kts higher than with 4 blades) - although this doesn't work in choppy conditions due to cavitation and you are stuck at low displacement speed.
Changed pitch to suit needs as required
- points
Cost of 4 replacement blades seemed excessive.
Normal failure was to lose all 4 blades
Losing all 4 blades leaves you unable to limp to a place of immediate safety ( a bent alu prop still works if you are in the middle of a deep water channel)
Lost blades when hitting rope (would expect an alu prop to survive this)
Last time I damaged the propulse prop, I never got round to replacing the blades and now use differing size alu props.
Pls PM if anyone wants to make an offer on the hub.
