Prop setup on G3 Bay 18 DLX

[KRC18D]

Gentlemen, I am running a bay 18 DLX with a Yamaha 115sho. It came from the factory with a 13 1/8 x 20 ss prop I’m seeing about 6000 rpm at 47mph. I am wondering if anyone else is getting about the same numbers. Because I have seen speeds up to 52 mph and as low a 44 under different conditions. Keep in mind this is still tournament loaded. Wondering if a different prop would allow me to see the higher speed all the time. Not sure what causes it to go faster sometimes. It feels like it just lifts really well at times and others not so much. Does anyone think this is a prop issue or something else?

[jarhead175]

New props out of the box are known to be inconsistent. Sometimes you get a good one next one might be a trainwreck. Call Mark at Mark's high performance Propellers he can tell you what you need.

[pmgoffjr]

First, weight is everything, so a light vs heavy load will change whatever it'll run a lot.
47 with a 115 is pretty good. You can't compare a tin center console with a fiberglass bass hull, complete different animals.

Most of the time, a bay boat owner wants a different result than a bass hull, top speed is secondary to quick holeshot, and rough water ability.
I think you can throw a lot of money at it, and see minimal results.

[KRC18D]

My load has not changed I always run with full tank with water in live well. Same amount of equipment, honestly it’s a lot less than others put in there boat. 5 3700 Plano boxes 1 small box of plastics 1 terminal box 6 rod combos. Probably weighs about 30 lbs max. I have very little storage so it’s hard to load much else. I just don’t get how my speed can change 6+ mph day to day.

[pmgoffjr]

Are you getting your speed from GPS or your boat speedometer? If it's your boats speedometer, they are always suspect. They work off water pressure through a tube to move a diaphragm in the instrument.

Heat makes a big difference, 50 degrees vs 90 degrees will easily make 5 mph.

Really and truly, if I'd rigged that boat with that motor, your results are certainly within expectations. You might find a few mph with some prop work, not exactly clear on what prop you have, if it's a pro series "M" wheel, it's probably pretty good, if it's just a vanilla prop, you might get some more with a change.
Do NOT equate your hull to a fiberglass bass hull. You can't run the same motor height on that aluminum as you can on glass.
Your boat is designed to run flat on the water, it won't lift on a pad. Not a negative, it's just different.

[KRC18D]

I’m getting all my numbers off gps. This boat has a pad hull much like express if your familiar with them. That’s why I said sometimes it lifts others it will not. When it does it gains about 10+mph. Just not sure what is causing it. Wondering if the prop is not proving enough lift.

[pmgoffjr]

Highly likely. If whoever rigged it just put a generic bladed prop, it's not going to do much. When it's NOT lifting, does it throw a big roostertail? Does the steering get stiff?

I really like powertech four blades on tin center consoles, rigged a bunch of them, and for all around performance, they've done a great job.

[KRC18D]

Yes to both. The prop is supposed to be a Yamaha according to my dealer. At times it will run very fast others it just won’t lift. It will blowout very easily if trimmed to high also. I am considering a 4 blade prop any suggestions? I talked with power tech today and they suggested 19 pitch 4 blade NRS4. Can anyone attest to this prop helping to lift their boat? Did you experience a drop in speed as well?

[pmgoffjr]

I would have picked the PTR4, the NRS4 is more of a nosebleed flats holeshot prop.
Before I bought anything, I'd drop the motor a little, your symptoms are absolutely saying you're a little high. If you can't get full trim, you're too high for your prop.

[KRC18D]

update. Well I’ve been working hard at testing different props from friends to try to find something that would help with my current situation. So far none of the props changed the boat handling and all were slower than current setup. A funny thing happened though yesterday when I took the boat out on the lake. I was idling through a shallow area when I ran up on a stump and got stuck. Had to give it some throttle to get it back off. Thinking nothing of it once I got out of the shallow area I hit the throttle and just about got thrown back over my leaning post from the force of acceleration. My Boat had never jumped out of the hole that fast. I then tested top end it was 51mph on a full tank. Just incredible! It appears the stump did something to the hull that fixed the problem I have been having for over a year. I have never heard of this happening to anyone else. Usually when you hit a stump it’s a bad thing but somehow it appears to have fixed my problems. Can’t believe it!

[pmgoffjr]

There's a thousand jokes I could make. I won't.
And the answer is absolutely no, I've never ever as in ever heard of whacking a stump improving anything, ever.

[jarhead175]

Only thing I can think of is you need to get a straight edge and check the hull right in front of the transom. Saw a guy post pictures of a tin boat on here that the transom looked low creating a lip on the bottom.