Can it be the prop?

[Walleye Gee]

I'm trying to get the best performacne out of my boat and I still don't think I'm there yet. I know for a fact (because I drove it) that the same 08 boat, 08 motor and prop was getting 51 MPH (GPS) @ 5700 RMP's. My boat is only getting 46 @ 5600. Can it be the prop? I don't have access to the faster boat anymore so I can't try swapping the props and I have talked to engine manufacture and they swear that the motors are within 1 or 2 horse power of each other. So the only thing I can think of is the prop. Am I missing something?

Oh another thing is that both boats have a jack plate but mine could be at a different height then the faster boat (never measure it) but I don't know if I could get much more speed with the RPM's so close.


Thanks for the help.

 

[QC]

Re: Can it be the prop?

Welcome aboard Walleye G! The answer is yes, but it is not the only thing it could be . . . Was the other boat a demo or actually had it been delivered to a user/friend? Weight is a huge factor, and my first thought was that they were loaded differently. Can you get the make, model, diameter and pitch of both propellers?

Engine make and HP would also be helpful, we could use that info to crank in some theoretical speeds etc. into a prop calculator . . .

 

[steelespike]

Re: Can it be the prop?

Your being pretty secretive.No boat info,motor info.no prop info.Are you positive the same brand,model and pitch prop? I think I would raise the motor to a point just before venting becomes a problem.Some run it on the ragged edge to get that little bit more speed.Just be sure it pumps water.As far as rpm tachs have been known to be off.Even though new you may want to check that the throttle is opening all the way.
At that speed having the windshield open, or the open bow covered or un covered could make a difference.

 

[Walleye Gee]

Re: Can it be the prop?

I didn't mean to be so secretive. Both were 08 rangers 620T with an 08 150 Evinrude and the props are a 19 tempest plus II (I think the dia is 14-3/8). The boat wasn't a demo boat it was it was my dads last boat. That why I know what the numbers I'm giving you are fact. Oh and they both were loaded about the same.

steelespike

What do you mean by check that the throttle is opening all the way?

I have move the motor around about 2" but I'm not sure if I have raised it as far as it could go. That's what I'm going to try this weekend but If that doesn't work what next?

 

[Dhadley]

Re: Can it be the prop?

I'm not sure the best (fastest) prop for a Ranger is a Tempest. However, let's assume we're comparing apples to apples. When were both boats run?

 

[slasmith1]

Re: Can it be the prop?

^^^^^
what he said different wind or current conditions could also cause the difference.

 

[Walleye Gee]

Re: Can it be the prop?

Both were not run at the same time. The numbers of my dad's old boat are from last year sometime in the spring. Even though my boat is an 08 I didn't have time to fine tune it until this year. I don't remember the conditions of the faster boat but my numbers are with very little wind 0-5 mph and both were running on mid size lakes.

 

[Walleye Gee]

Re: Can it be the prop?

One other thing getting back to QC comment about weight. My dad's old boat had a 36 volt trolling motor but I have a 24 (one less battery) All of the batteries are located in the back of the boat.

 

[Walleye Gee]

Re: Can it be the prop?

I ran my boat this weekend and found that if I move my motor up as far as the jack plate will go I don't get any more speed but the RPM's go up to 5800. I do have a big rooster tail.