Sharrow Props

[Submariner]

Martin, thank you for this second 'user perspective' video, the partner to your first 'data intesive' video. This second one helped me get a good sense for what living with one of these modified 4 or 5 blade props is like vs. my 250's 3-blade 'factory prop'. One observation you made in video #1 was the difficulty you had in getting accurate fuel burn (mpg) numbers off the Yamaha engine display. That's sure true for my 250. 1.2, 1.4 and 1.6 are the only numbers I've ever seen when at planing speeds; nothing in-between them. For those of us with the basic electronics package, do you have any suggestions for getting better real time fuel burn data? Thanks again for the time you have put into this project.

Thanks for watching! I'm glad you found the second video helpful. Plus, I think it's great when LaZina gets in front of the camera.

The Garmin Chartplotter USED to show mpg. In April 2021, a software release "broke" it. I dunno why or what. I've spoken with Garmin about this, as it worked for the first year we owned the boat. mph / gph = mpg, those numbers are available on the chartplotter. Today, you can get mpg on the chartplotter only if you do NOT have the Yamaha to N2k gateway installed. All the new boats (2023 and newer) come with a J1939 cable for the chartplotter and no longer come with a Yamaha N2k gateway. The J1939 cable plugs engine data directly from the J1939 network into the chartplotter and mpg can easily be shown on the chartplotter. For those of us running the Lenco Autglide (auto-pilot for the trim tabs), it requires engine data to operate (engine RPM, specifically), it requires that data via Nema2k, which is only possible with a Yamaha to N2k gateway installed. If you ran a J1939 cable and a Yamaha N2k gateway to get both to work, the Chartplotter would see two engines.

My setup is Yamaha N2k gateway, which means I get MPH ad GPH on the chartplotter, but no mpg. Which leaves the Yamaha display for their 1.2, 1.4, or 1.6... I've also seen .9 (bad bad number... Lol).

This has been somewhat frustrating for me, but something I've just learned to live with. That's why I illustrated that in the video. I look for 30mph / 20gph which I know is 1.5mpg. If the numbers are too far apart, I'll just do the math on my phone. MPH / GPH and get my mpg number while driving.

 

[jack_patricia]

Of course, quite a simple workaround I can now see. Thank you, Martin.

 

[Submariner]

Do you have a 250 or 300 Yamaha? What size PowerTech did you put on?
I have a 2023 C248 w/ 250 and I need a new prop.

Call PowerTech and talk with them directly. They've got a lot of great data from me that should help them tune other boats built by Fluid Motion.

The F250 and F300 are the same 4.2l v6 from Yamaha. It's the same Yamaha service manual. The tune is different such that the F250 was designed for 87 octane gas and the F300 was designed for 89. However, in Puget Sound, most fuel docks only offer 87 octane. There's a company called NizPro that can flash the ECU on a F250 and get it over 300hp. However, once flashed, it'll require 89 octane fuel. That's why I haven't sent my ECU off my F300 to them. They claim to get about 330HP out of an F300. NizPro claimed they could get me the Prince Rupert to Shearwater numbers (MPG) I needed without changing the prop. But since I can't reliably get 89 octane, I focused on prop sizing instead.

That exhaust tube extension modification PowerTech has really makes a big difference in the midrange when compared to a conventional prop.

 

[Turbo]

RT25 stock prop info. the weakness if found was mid range compared to the other props. for me getting over 2 mpg was a goal. slow and fast was no problem. I have found a sweet spot at 15 mph with trim tabs all down getting 2 mpg. enjoying a trip to st Augustine fl with another rt 25. these boats are a plenty!

 

[Submariner]

I received my exhaust extension tube for my Prototype SCE5 prop on my R27-OB today. I'll get it installed this weekend, and will do a short video on how to put it together, what loctite to use, etc... They're anodized black and look sharp! Pictures can be found on the website below.

I've also updated our website with all the information and links to the videos about the prop testing and such.

LetsGoChannelSurfing

www.letsgochannelsurfing.com