Three blade vs two blade, worth it?

[Wani II]

Have a wonderful little Newport 28 mkii with a rebuilt (only 60 hours to date) Universal 5416. I was wondering if the cost of a three blade prop is worth it. The double on the shaft now was new in 2000 or about 300 hours back. My reason is we will be heading up the Columbia River next season and fighting a bit of a current. Any ideas if I would see that much better performance and if so any opinions on types and brands? Other things to take into consideration.

[mglonnro]

In a completely different boat, a Hanse 388, we were doing sea trials and checking the motoring speeds with a 2-blade folding prop. We were getting about 4.5-5.5 knots with conservative RPMs. The dealer told me (if I remember correctly) that switching to a 3-blade folding prop would gain about one knot of speed.

It seemed like quite a big difference.

[NorthernMac]

If I swapped out a prop, it’ll be for a auto prop

[rbk]

Check out the Campbell Sailor prop below. More power, better balancing of a 3 blade with considerably less drag than a standard Michigan for around the same price.
http://www.westbynorth.com/campbell-sailer/

[Wani II]

Thanks everyone.

[a64pilot]

From a speed perspective a two blade will be faster, but not measurably so, unless of course you have such a small prop that you can cavitate it.

Reason is there is less skin drag on a two blade prop.
Now if you replace a two blade prop that didn’t have enough pitch to be correct with a three blade that does, then yes the three blade will be faster.

Now a three blade prop will have more “bite” very similar to larger tires on a car, so acceleration will be better and maybe driving into wind and waves will be better, but it will also have a lot more drag under sail.

[Wani II]

I was told that the prop I have is a bit larger than what was original, 12" rather than the 10.5" that is stated on the factory delivery sheet from 1985. Never thought about measuring it last time she was on the hard. I have a couple of quotes out (Thanks to rbk) to compare prices.

[rbk]

Originally Posted by Wani II

I was told that the prop I have is a bit larger than what was original, 12" rather than the 10.5" that is stated on the factory delivery sheet from 1985. Never thought about measuring it last time she was on the hard. I have a couple of quotes out (Thanks to rbk) to compare prices.

If you’re getting a quote for a Campbell remember it will most likely be in Canadian dollars. They’re also good about re-pitching a few times to tweak it, just ask before you buy so it’s on the receipt.