New prop on the boat (FINALLY!!)
After visiting the SYdney Boat Show and talking the guy at Solas into selling me an $850 prop for $700, I've now fitted it to the boat and done the testing. Here's the story (click "read more").After purchasing "Panic" about 18 months ago I was happy with it's performance but not thrilled. The previous owner's skiing habits were a little different to ours and the boat wasn't quite "right" for us. The previous owner would load the boat up with fuel, people and gear, then ski from the boat (doing deep-water starts) all day. We, on the other hand, load the boat up, cruise around to find a vacant beach, unload all the gear and people then ski with minimal people in the boat. This meant the boat was seriously "under propped" for our purposes and revved it's head off!
So I got a plan - buy a prop with more "bite", sacrifice some acceleration and gain some top-end speed etc. We didn't need to drag big fat blokes out on slalom skis as we mostly do beach starts.
A Solas TorqueMaster with 21" pitch was selected and purchased a few weeks ago and was fitted last weekend. Here's the table of results (all speeds are km/h):
| RPM | Old Prop 17" 3-blade | NEW Prop 21" 4-blade |
| 2000 | 14 | 19 |
| 2500 | 21 | 35 |
| 3000 | 31 | 44 |
| 3400 [1] | 38 | 51 |
| 3500 | 40 | 53 |
| 4000 | 46 | 60 |
| 4500 | 56 | 71 |
| 5000 | 59 | 76 |
| 5400 [2] | 63 | 86 |
| 5500 | 64 | - |
| 6000 | 75 | - |
- 3400RPM is a comfortable speed for the motor. We've worked out that this is about the most economical RPM for tooling around, looking for beaches :)
- 5400RPM is as hard as the motor will rev with the new prop. This is about smack-on where Mercury claim maximum horsepower.
Now what all this means is that I've dropped the RPM across the board by about 1000RPM. In other words, the motor revs lower to achieve the same speeds, even though it doesn't rev out as hard (this is a good thing). By lowering the RPM across the board, the engine will be more efficient at each speed by between 10-20%. We save fuel, get to our favorite beaches faster and more economically AND the boat is easier to drive (not to mention faster and smoother). All up I'm VERY satisfied with the results :) Here's some photo's of the new prop.
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