Evinrude E-TEC 60HP prop size....need help!!

[kingy1978]

Hey guys I have a Makocraft 440 Estuary Tracker Tournament with a 60hp Evinrude E-TEC currently it has a 17 pitch stainless viper prop which tops out at about 60km/ph. My mates hornet trophy with a 40hp Yammie 2 banger is about 3-4 kilometers slower which got me thinking (and pissed me off) maybe I should change my prop?

I know hole shot won't be as good but if I went to a 19 pitch or 21 pitch prop how much more top end will I get out of the boat? Which one of these would you guys recommend? Also just how much will this affect my hole shot? Personally I don't mind it being a bit of a slug out of the hole if it flies when I'm hookin' it up river...

Any advice or opiions would be greatly appreciated, Thanks guys!!

[Justin Boyle]

I would suggest ur prop is too big. Not sure of the gear ratio though. What rpm are u doing flat out?

[kingy1978]

Boat tops out at about 5500rpm

[Brad Y]

If your right on the max reccomended RPM then dont change your prop. The best way to go faster is re power. But you can do a few things to get better performance. Make sure your cavitation plate is clear of the water is the big one. Once you do know that then you can play with props etc. You could by the sounds of it go to a 15p 4 blade, but you wont gain any speed, just your holeshot etc might improve.

[kingy1978]

60hp is max power for my boat. What is the cavitation plate? how do i check if its free of water? I thought a prop was like a gearing system on bike where a higher pitch equals higher top end buts less punch down low, am I wrong about this?

[Justin Boyle]

This can be a handy tool.

http://www.rbbi.com/folders/prop/propcalc.htm

Your gear ratio is 2.67:1 The prop Brad suggested would be ideal if the motor was 2:1

According to that prop calc your motor with a 17p would be doing about 30mph at 5500. Thats shy of your 60kmh somewhat so I suspect that the top speed reading you got is a little out unless of course you got that reading with a GPS.

Your motor at WOT should be running in the optimum rev range. Evinrude states that for you that is 5500-6000rpm. If you got a prop 1 pitch higher your revs would drop from 5500 to 5300. I think you need to get a smaller prop and hopefully the extra revs you get will get you a little more speed but most importantly give you better acceleration and allow you to carry more people/equipment.

P.S. I suspect your makocraft is a little heavier than your mates quinnie. The quinnie would have the millenium hull too I think which is probably a little slipperier in the water.