Bertram 28 prop pitch

[cmccool]

Hi guys

I repowered my B28 last year with new 5.7l Mercruisers rated at 5000rpm WOT running 1.5 gears. Unfortunately, one of my engines was 300rpm off the other at WOT so this winter I got a replacement under warranty. The down side is that my propeller testing was a waste of time because one of the engines was roughly 60hp underpowered and I have to start all over again.

Last year, with 17x15 props, I was pulling 4600/4300 rpm at WOT so I think I will still be a bit overpropped with the repaired engine.

I have a set of Acme 4 blade 14.5x14.25 that I am going to try out as they are just taking up space in my garage.

So the question is: what prop/pitch are you guys using on your engines that turn up to 5000rpm and what speed are you seeing at WOT and cruise.

Thanks
Cliff

[Skipper Dick]

Cliff,

I have a 1983 B28 with 300 HP Horizons with 1 1/4 shafts. The props are 17x16 with WOT at 4400-4800. I cruise 20+ kts at 2950 rpm and at WOT I've got her up to 32kts. I get 1.1-1.25 knots per gallon depending on conditions.

Dick

[Preston Burrows]

Cliff:

Have a read of the discussion we had a while back at the B28 site about propping.............unfortunately I never got an answer to the same question from a real life B28 owner/operator when I was considering 5,000 rpm motors in my repower options.

I repowered with 260hp 4200-4400 w.o.t. motors ,1 1/8" shafts,1.5 :1 transmissions,17x16 3 blade props and my performance numbers are the usual stock B28 FBC numbers.

http://ebiz.netopia.com/bertram28/discu ... &UID=10110

[cmccool]

Thanks guys

I don't think I am too far off with the 17x15 but unfortunately, with the one engine underperforming by 300rpm, I don't really know where I am and to add insult to injury, I dinged one of my props when I pulled the boat.

Having to send a prop in to get redone when I know it is the wrong pitch just doesn't sit right. I don't mind spending money, but I sure hate wasting money.

I am going to give the 4 blade a shot next month when I splash and see how it goes.

thanks
Cliff