Steelspike Update On Prop Selection/Question

[treeguyus]

If you recall:

Prop Suggestion for 1999-2000 Yamaha 4 Stroke Outboard
Would like to get better hole shot (faster on plane). The 100 hp is on a 2025 Lund, slightly under powered. With one person gets up on plane quickly. Slow to get on plane with two people and live well full of water. Currently it has a 17 pitch prop. Should I drop pitch to a 16 or 15? Would stainless be a good option? Any other suggestions RPM range 5000 to 6000. Prop reccomendations appreciated


Update: I put on a 15 pitch four blade solas, hole shot much improved, top end 31 mph gps and stays within the 5000 to 6000 RPM range and I can back off throttle and cruise on plane 25 mph to 29 mph.

My question what would a 13 pitch 4 blade do or would I be at a point of diminishing return. The performance is much improved thinking a repower might not be necessary. With this in mind would stainless be noticeably better. The plus side of a lighter weight engine on the back for tiller is balance when back trolling. Also thinking of moving the rear starting battery from the back to a the third tray on the bow with the other two for my 24 volt system. What would shifting the weight of a battery forward do? A lot of ideas but may not make a difference thanks for your time

 

[steelespike]

Need to know your lightly loaded actual wot rpm and speed.Using the numbers you gave me I'm mo guessing 5700 rpm.
My info indicates the 100 has an odd ratio of 2.31.
Assuming 5700 is correct a 13" could put you at about 6000 speed would be about 28. further improved hole shot and ability to stay on plane.
Would struggle less as you add weight.It will require more rpm to go the same speed as the 15" Not necessarily more throttle as it will be easier to reach rpm.
Moving the battery forward obviously has a double affect of getting the stern up better and fights bow rise on hole shot.
It may slow top end but be slightly easier to keep on plane.
Maybe you can test with some jumper cables just to run the motor.
Somebody on here noted that as he move 3 ft toward the stern he gained almost 1 mph.
You might consider lightening the load in a bow locker.
Also eliminating stray weight could help.
As far as ss props if you boat where hard contact is likely ss costs more to repair.
If you boat where soft contact(mud,sand) is likely the ss will resist damage better,but of course cost more to repair when necessary.
A ss could improve overall performance but is it worth up to 3 times the cost of aluminum.

 

[treeguyus]

Your right, will run the boat today with just me aboard and let you know. Your guess at 5700 might be a bit high, thinking it was 5500. Did notice while back trolling my GPS speed in reverse was slower but my RPM was a bit higher, from 900 to 1000 rpm with the new prop. Sorry what is wot. Will post todays results later. thanks

 

[steelespike]

Guessing rpm surely isn't very accurate but it did tell us your in the ball park.
WOT is "wide open throttle)
Reverse rpm would be different; prop isn't designed to run in reverse.If I understand back trolling the
stern surely has more drag than going forward.Perhaps that is why you "back troll"?

 

[treeguyus]

Thanks on the WOT now I know. For back trolling it slows the speed as a motor in reverse goes slower with the transom in reverse, gives very good control too. So if the 13 pitch would slow the speed in reverse it would be a plus for sure.Less shifting I and out of gear to achieve a slower speed, if you follow what I mean and sure you do

 

[steelespike]

Seems like a trolling plate would make more sense than back trolling. Easier to control
no shifting required.Seems like having to shift to control speed would prematurely wear the shift dogs.

 

[Sea Rider]

When with no wind, what about smoke entering deck when reversing, is it a very noticeable unconfortable situation ?

Happy Boating