4 Blade Propeller

4 Blade Propeller

Postby Miker » Mon Aug 28, 2017 10:43 am

After sailing my Top Hat for just over 8 years, I've finally got around to working out a better alternative to the standard 3 blade prop on the 8HP 4 Stroke. It hangs off the back and is a standard leg, so a bit short, but it works quite well. The only issue really was that there was very little thrust in reverse, so docking and maneuvering in close quarters was tricky.

I bought a 4 blade Solas 8.5 x 7 at the boat show, at least I think it's the 7 inch, not the 5. All I know is the guy said "this is the one for your Top Hat, because it's not "that" heavy to need the 5.

Yesterday, I installed the prop and went for a spin. First impressions were that it actually accelerated quite quickly. The boat got to speed well and the engine could actually reach top end revs. With the standard 3 blade, it always felt like it was labouring at full throttle.

So now, I get 5 knots easily at less revs than before, and can almost get 6.5 at full throttle. At least that's what the GPS told me.

After the test run we were coming in to our mooring in Careel Bay, when we noticed Wind Dancer, a Citation 34 was sitting very close to a jetty but with no lines out. So we went in fairly close in to check and see if they were OK, as they'd just bought the boat. It was a really, really low tide and we hit bottom! As I suspected, they'd run aground. We'd both come to a dead stop, even though we were on a similar path to the one we always take in easterly winds to the mooring. The 3 blade prop would never have managed enough thrust to reverse off, but the 4 blade did it without so much as a wimper, a few changes in direction backwards and we were off in a flash. Wind Dancer was a little more stuck than us, and we may have been able to tow him off, but I wasn't prepared to risk both of us being stuck until 9pm when the tide would have been high enough to float off. He was happy to sit and wait, because there was no real way of kedging in such close quarters.

I can't recommend the Solas 4 blade enough, so if you've an outboard that wasn't designed for your boat, change the prop. You won't regret it.
"Dulcamara" - MKIII
Careel Bay, Pittwater
"Order of the Tipping Dinghy" 2017
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Re: 4 Blade Propeller

Postby Shaun » Mon Aug 28, 2017 4:24 pm

Nice one. I have been quite happy with the 4 blade 5 inch prop on the Tohatsu 9.8hp 2 st. The engine seems to rev a little higher than the 6.5inch 3 blade prop, but I believe the higher revs are better for the 2 strokes. Also a sutle but noticeable difference in thrust both fwd & reverse.
"Blue Moon" MkIII Junkette rig,
Camden Haven River,
Mid Nth Coast, NSW

Order of the Albatross - 2011
Order of the Tipping Dinghy

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