Did some fishing today and remembered to snag some photos of the Garmin while I was running.

I'm hoping for advice on a better prop for my setup.

Boat is a 2003 Sea Ranger 19' HardTop
2015 Honda BF115D (2.14 ratio)
Current Prop is a Honda Aluminum 15x13P 3-blade

Today's load:

• Me only
• ~30gal fuel
• 10gal fresh water up front
• 5-10lbs gear
• Bottom Painted
• Yamaha T9.9
• Radar as seen

Saltwater, calm day at slack tide, no real wind.

I was able to get to 5800RPM max at 28.1mph for a 15% slip.
Cruising is between 22-25 as you can see, consuming 5.5-6.0 gal/hr.

I feel like there is more efficiency and speed to be had out of this setup, but maybe I'm wrong.

I'd try a 14" x 12" Yamaha Talon Pontoon SDS and expect a top speed of ~30 MPH with comparable fuel economy improvement. But what you will really notice is much improved handling.

Quote from: Tom C on May 01, 2024, 07:08:59 PMI'd try a 14" x 12" Yamaha Talon Pontoon SDS and expect a top speed of ~30 MPH with comparable fuel economy improvement. But what you will really notice is much improved handling.

Is there any type of adapter needed going from the Yamaha to the Honda lower?

I'm pretty surprised that it didn't rev higher considering there's people with the super similar setups running 14x15P props and getting closer to 6k rpm.

Assuming the trim was adjusted accordingly
Thinking a 4 blade solas would be a good fit. Just a guess.

QuoteIs there any type of adapter needed going from the Yamaha to the Honda lower?

The splines are the same for Yamaha and Honda so I suspect you just use the existing thrust washer and prop nut, but I have never actually put this SDS prop on a Honda, so can't be 100% sure.

At any rate, it is an expensive prop, so best to experiment first. I have the 15" pitch version you could test with but I know that's too much pitch.

Do you have a pic of the back of your boat out of the water? Any fin on the motor? Any trim tabs? What hole is the motor mounted?

Quote from: Tom C on May 01, 2024, 09:21:52 PM

QuoteIs there any type of adapter needed going from the Yamaha to the Honda lower?

The splines are the same for Yamaha and Honda so I suspect you just use the existing thrust washer and prop nut, but I have never actually put this SDS prop on a Honda, so can't be 100% sure.

At any rate, it is an expensive prop, so best to experiment first. I have the 15" pitch version you could test with but I know that's too much pitch.

I'd love to try it out, I'll message you about it. Everyone will laugh at me for having a Yamaha prop on a Honda though! Haha!

Quote from: Fisherdv on May 01, 2024, 09:38:55 PMDo you have a pic of the back of your boat out of the water? Any fin on the motor? Any trim tabs? What hole is the motor mounted?

Sure do!

No fin, I took that off first day of ownership. Trim tabs yes, no zinc on the bottom of the tabs as Tom C said. Motor is all the way down currently.

If the motor is all the way down, it would certainly benefit form being raise a hole or two.

The transducer is problematic too, as it is mounted close to the motor (not much do do with that because of the trim tabs) and to starboard where it will have a much greater chance of entraining air onto the propeller's flow of water.

I would move the transducer to port.

Also be sure the trim tabs are anointed a little above the bottom edge on the transom so they do not interfere with the slipstream when fully retracted.

My first thought is motor maybe mounted too low, hard to tell without a picture of that area.

Also, check to see if your throttle cable is adjusted correctly to spec. You may not be able to get full throttle if not.

With a 13p prop, I would think you should be at higher max RPM than 5800, unless your boat is loaded really heavy, or bottom paint in bad shape.

Everybody alway suggests the throttle cable. It's never the throttle cable on modern motors.

Who has performance reports for a 19HT? Can be any HP.

Quote from: Tom C on May 02, 2024, 10:58:18 AMEverybody alway suggests the throttle cable. It's never the throttle cable on modern motors.

Who has performance reports for a 19HT? Can be any HP.

I like to check the easy things first. Boat is 2003, motor is 2015. Whoever mounted and setup the motor may not have set it correctly.

If throttle cable or motor mount height is incorrect, you will never get ANY prop to perform correctly. You would be just pulling your hair out.

Some extra info:

• Yesterday I did notice that the newly mounted transducer was way too low and caused some increased spray. It's now moved up and will hopefully help cut back the spray.
  
• It did cause the outboard to ventilate a little earlier than before the transducer was mounted, but nothing else
• If there's still an early ventilation issue tomorrow I'll move the mounting block and transducer to the port side
• The prop is actually a 15.5" diameter 13P
• The bottom paint is fresh and new as of 3 months ago. It's been in the water 5 times since it was redone

Some photos for fun:
 

Whoa! there been so many threads about props recently I'm getting them confused.

Ignore my recommendation of the Pontoon SDS. You have a large gearcase, and as we discussed in your other thread, the anodes on your trim tabs were the root cause of your low boat speed, but you still have those screw heads there. Am I seeing that right? pan head or Truss head would be much better The tranducer is a real problem..

Yes, your boat is racially slow. It should be good for high 30s. I found a performance report for a 21HT with a Honda BF115B that hit 35.4 at WOT

I highly doubt the transducer is the main problem. Almost all Arimas have their transducer mounted there, me included. No need to move it to the other side. Just adjust the height correctly. About half with the boat bottom.

So here's a story. A friend bought a nice used boat 22' in Montana, brough it home to Seattle. It had a relatively new Honda BF225, a very reliable solid motor. I knew from experience this boat should go 47-49 MPH with 225 HP. We test ran it in Puget Sound one early spring day, launching at Shilshole.

The boat ran great, started right up, sounded wonderful, climb up on plane and to top speed, no problem. But it topped out at only around 44 MPH. That was fine, but the RPM was a little low too, and I know it was propped appropriately for thermal higher top speed.

What was going on? (this is a challenge for you all)

Quote from: Tom C on May 02, 2024, 11:47:38 AMSo here's a story. A friend bought a nice used boat 22' in Montana, brough it home to Seattle. It had a relatively new Honda BF225, a very reliable solid motor. I knew from experience this boat should go 47-49 MPH with 225 HP. We test ran it in Puget Sound one early spring day, launching at Shilshole.

The boat ran great, started right up, sounded wonderful, climb up on plane and to top speed, no problem. But it topped out at only around 44 MPH. That was fine, but the RPM was a little low too, and I know it was propped appropriately for thermal higher top speed.

What was going on? (this is a challenge for you all)

Transducer mounted too low and bolt heads causing turbulent water under the trim tabs? 

If you have turbulent water back there causing ventilation, would you get a pretty high amount of slip?

Winner winner chicken dinner!

Quote from: Tom C on May 02, 2024, 11:38:14 AMWhoa! there been so many threads about props recently I'm getting them confused.

Ignore my recommendation of the Pontoon SDS. You have a large gearcase, and as we discussed in your other thread, the anodes on your trim tabs were the root cause of your low boat speed, but you still have those screw heads there. Am I seeing that right? pan head or Truss head would be much better The tranducer is a real problem..

Yes, your boat is racially slow. It should be good for high 30s. I found a performance report for a 21HT with a Honda BF115B that hit 35.4 at WOT

That wasn't my thread but I did read that. I have some pan head bolts for it I'll throw on there right now actually.

This prop has an absolutely insane amount of surface area to it, I almost wonder if the 15.5" of it is causing it to drag a bit. It does get on plane quite easily though.

Quote from: Nanserbe on May 02, 2024, 12:09:23 PM

Quote from: Tom C on May 02, 2024, 11:38:14 AMWhoa! there been so many threads about props recently I'm getting them confused.

Ignore my recommendation of the Pontoon SDS. You have a large gearcase, and as we discussed in your other thread, the anodes on your trim tabs were the root cause of your low boat speed, but you still have those screw heads there. Am I seeing that right? pan head or Truss head would be much better The tranducer is a real problem..

Yes, your boat is racially slow. It should be good for high 30s. I found a performance report for a 21HT with a Honda BF115B that hit 35.4 at WOT

That wasn't my thread but I did read that. I have some pan head bolts for it I'll throw on there right now actually.

This prop has an absolutely insane amount of surface area to it, I almost wonder if the 15.5" of it is causing it to drag a bit. It does get on plane quite easily though.

Could be right. Maybe a 13x15p, 4-blade or 13.5x15p  prop, in the same aluminum Honda prop.

Quote from: Nanserbe on May 02, 2024, 12:02:29 PM

Quote from: Tom C on May 02, 2024, 11:47:38 AMSo here's a story. A friend bought a nice used boat 22' in Montana, brough it home to Seattle. It had a relatively new Honda BF225, a very reliable solid motor. I knew from experience this boat should go 47-49 MPH with 225 HP. We test ran it in Puget Sound one early spring day, launching at Shilshole.

The boat ran great, started right up, sounded wonderful, climb up on plane and to top speed, no problem. But it topped out at only around 44 MPH. That was fine, but the RPM was a little low too, and I know it was propped appropriately for thermal higher top speed.

What was going on? (this is a challenge for you all)

Transducer mounted too low and bolt heads causing turbulent water under the trim tabs? 

If you have turbulent water back there causing ventilation, would you get a pretty high amount of slip?

Good guess, but no. That doesn't mean this is not the problem here though.

QuoteCould be right. Maybe a 13x15p, 4-blade or 13.5x15p  prop, in the same aluminum Honda prop.

So everybody understands what is going on here, Nanserbe has a Honda BF115B which uses a large size (4.75) gearcase, not the more common-on-Arimas intermediate size (4.254) gearcase, so it can't use such small propellers.

He currently is using an aluminum 15-1/2" x 13" Honda branded three blade propeller made by Solas (same as the Amita 3).

His top speed is ~28 MPH when it should be ~38 MPH, so something is seriously off, and apparently the anodes on the trim tabs aren't it.

I mentioned my friend's boat that was surprisingly slow, and it turned out one spark plug lead was loose. That was it. It was running (just fine) on five of its six cylinders, with a proportional low of HP and speed.

The test to see if the transducer has anything to do with this, or not, is simply to go run the boat with the transducer flipped up out of the way and secured.

All transom mount transducers have a flip up feature to prevent driftwood from taking them out. I use a little cord tied off to it to hold it up out of the water for testing. It just takes it out of the equation.

Quote from: Tom C on May 02, 2024, 12:46:55 PMThe test to see if the transducer has anything to do with this, or not, is simply to go run the boat with the transducer flipped up out of the way and secured.

All transom mount transducers have a flip up feature to prevent driftwood from taking them out. I use a little cord tied off to it to hold it up out of the water for testing. It just takes it out of the equation.

I'll give that a go tomorrow after coming back from fishing.

I don't think that's it since I was getting the same top speed before the transducer was installed.