Backup Prop

[ralphy670]

Looking for advice on a backup prop for my boat. Currently have a Yamaha reliance sds in an 18 pitch on a F150 mounted to a smoker craft 182 explorer.

wot is 5700 with normal load and speed is 48 mph.

with just me I can hit 6000 at 49

I would like a 4 blade aluminum as the backup but don't know what pitch I should get. I am looking at turning point currently but open to opinions and suggestions.

thanks

 

[QBhoy]

Generally but not always, a 4 blade will have a bigger diameter than the standard 3 blade, so will generally drop the rpm a little compared to the same pitch 3 blade. They also usually will drop top end speed compared to the same pitch 3 blade...but perhaps gain hole shot and grip in a tight turn.
You would maybe want to try before you buy.

Only thing i would say is that you should maybe do a few test runs again with your current set up before hand. If you can gain 300rpm but only 1mph you are fair losing some efficiency at the top end.

You are seeing some good numbers though. If you aren’t struggling with getting out the hole and generally happy, I’d be tempted to get a good well known performance 3 blade stainless prop and keep the one you have for a spare ?

 

[Scott06]

Drop and inch or so of pitch for a 4 blade so go with a 16" or 17". Had good luck with a Michigan vortex 4 blade, relatively inexpensive.

 

[Sea Rider]

Need to know what's the min-max wot rpm range factory stated for that outboard. Is 6 K wot revs the max stated ? What are you tring to better, hole shot or top end speed. Both scenarios will vay accordingly to how loaded you like going boating with.

Happy Boating

 

[ralphy670]

6000 rpm is max. Iam not a speed demon and would rather better fuel economy.

 

[WesNewell]

You'll get the best fuel economy with the least amount of drag. For that you need proper engine height and trim.

 

[Sea Rider]

6000 rpm is max. Iam not a speed demon and would rather better fuel economy.

The current prop is an excellent performer, personally would stay there specially if runs to max 6 K while solo boating and 5700 as usually loaded, both scenarios achieves nice hole shot and speed.

Ideal is to achieve the least lower leg drag with top prop thrust for spot on boating, but as there's too much forum tech controversy going on about which is the perfect OB/transom height and trim, will leave it there...

The best fuel economy with current prop will be to plane the combo fast, once on plane reduce throttle to a position that maintains excellent plane while the OB runs smooth to the ear.

Happy Boating.

 

[ralphy670]

Thank you all. I appreciate it