400 with 1.76 transmission prop choices

[SONIC]

I guess people were still looking for a bit more from the 16x15 so they dropped it to the 16x13.9 (agreed odd number there, they are usually in increments of .25)

I'd go that route personally, when I need a spare I'll probably grab one.

[dakota4ce]

I guess people were still looking for a bit more from the 16x15 so they dropped it to the 16x13.9 (agreed odd number there, they are usually in increments of .25)

I'd go that route personally, when I need a spare I'll probably grab one.

Except is has enough more cup to act like the 15” in a basic sense. It must offer an advantage for hooking up better.


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[dakota4ce]

I ran my 16x15 heavy as a MF in my SL and it was plenty of grunt. 5100# of water plus 300 lead on wakeboard plane like a rocket.


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[larry_arizona]

16x13.9 with heavy cup may be more efficient than a 16x15


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[SONIC]

It's my understanding that more cup has more holding power in the water so it should hook up better with less slip out of the hole.
More cup also can increase top speed.
how the hell any of the physics work on a propeller Is over my head haha

I'm waiting on one of these to become available for the wake boat segment:
https://www.sharrowmarine.com/

[larry_arizona]

It's my understanding that more cup has more holding power in the water so it should hook up better with less slip out of the hole.
More cup also can increase top speed.
how the hell any of the physics work on a propeller Is over my head haha

I'm waiting on one of these to become available for the wake boat segment:
https://www.sharrowmarine.com/

Lol, for $5000 I will wait. Also would not run a Stainless steel prop on a V drive unless it had some form of engineered sheer pin.



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[SONIC]

Lol, for $5000 I will wait. Also would not run a Stainless steel prop on a V drive unless it had some form of engineered sheer pin.



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I agree it's probably still years out from being affordable but the tech is very cool and apparently it really works and reduces fuel usage and plane speed considerably which would be awesome on a wake boat. They also have videos showing it essentially eliminates cavitation at the prop edges.
if they can CNC it from stainless they can do the same from Nibral.

They started them for tankers where a 1% increase in fuel economy is millions of dollars

[mmmkay]

I was running the 3337 (16x15 with 0.075 cup) on my 2020 SL400. We run full ballast, 500 lbs of lead (all towards the back to get the nose up to about 9.5 degrees), and a crew of 6-8 adults. Had no problems surfing 11.4 mph at 3k feet of elevation (3750 RPM +/-150 at depending on load and pitch), but fully weighted on a hot day we could not plane out. We don't wakeboard so this is not usually a problem for us. But, we took the boat up to 5k feet of elevation and it could barely hold 10.0 mph fully weighted. We came prepared and pulled the boat out to put on a 3409 prop (16x13 with 0.150 cup) and it solved all of our problems! Shockingly surf RPM is exactly the same but we have more holeshot, it gets up to speed faster, is much more responsive, and if we hit a wave it can easily temporarily rev above 4k to maintain speed (something the 3337 could not do). We can even slowly plane out fully loaded at 5k feet now. I was not expecting that out of the 400 motor - thank you Supra Launch! Fuel efficiency for surfing is also slightly improved - went from averaging 7 gph to 6.5 gph. Even though it's running the same surf RPM, the motor sounds like it's not working as hard and is slightly quieter. Top speed dropped from 37 to 34 mph so fuel efficiency while cruising at 25 mph (3800 RPM vs. 4100 RPM) has gone down but it's a small price to pay for a WAY better set-up. I highly recommend the 3409 for anyone with the 400 motor and 1.76 transmisison. I was originally planning to only use this prop when we were boating at elevation but we're leaving it on all the time now. Even at 3k feet it's a noticeable difference and much better.

[SONIC]

Awesome feedback.

[larry_arizona]

I was running the 3337 (16x15 with 0.075 cup) on my 2020 SL400. We run full ballast, 500 lbs of lead (all towards the back to get the nose up to about 9.5 degrees), and a crew of 6-8 adults. Had no problems surfing 11.4 mph at 3k feet of elevation (3750 RPM +/-150 at depending on load and pitch), but fully weighted on a hot day we could not plane out. We don't wakeboard so this is not usually a problem for us. But, we took the boat up to 5k feet of elevation and it could barely hold 10.0 mph fully weighted. We came prepared and pulled the boat out to put on a 3409 prop (16x13 with 0.150 cup) and it solved all of our problems! Shockingly surf RPM is exactly the same but we have more holeshot, it gets up to speed faster, is much more responsive, and if we hit a wave it can easily temporarily rev above 4k to maintain speed (something the 3337 could not do). We can even slowly plane out fully loaded at 5k feet now. I was not expecting that out of the 400 motor - thank you Supra Launch! Fuel efficiency for surfing is also slightly improved - went from averaging 7 gph to 6.5 gph. Even though it's running the same surf RPM, the motor sounds like it's not working as hard and is slightly quieter. Top speed dropped from 37 to 34 mph so fuel efficiency while cruising at 25 mph (3800 RPM vs. 4100 RPM) has gone down but it's a small price to pay for a WAY better set-up. I highly recommend the 3409 for anyone with the 400 motor and 1.76 transmisison. I was originally planning to only use this prop when we were boating at elevation but we're leaving it on all the time now. Even at 3k feet it's a noticeable difference and much better.

This is awesome, sounds like the 16x13.9 .105 cup will be a good choice under 2000 feet


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