R23 Yamaha prop size and WOT match.

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Whynot?

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Jan 21, 2020
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8
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Beverly Ma
Fluid Motion Model
R-23 (Outboard)
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Why Not?
Hi Guys
Just bought a 2018 R23 with a 200 Yamaha. Great boat. Q. At WOT the RPM are close to 5800. Yamaha. 200 WOT range is between 4500 - 5500. I’d like to put a four Blade prop to help with following seas and holding the boat on plan and lower RPM. What do you think? What do you suggest?

THANKS
Chris
Why not?
 
We have the same boat so I’ll be interested in the responses. FYI. I’m able to get on plane and cruise comfortably at 4600-4800 rpm at 25-27 mph. Three bladed prop.
Karl
 
I've got the stock 3-blade prop on my F200 as well. WOT is about 5700, but I rarely go there.

As Karl stated, my comfortable fast cruise is 4400 at about 26mph. It's got an adequate hole-shot, and I'll probably stay with the stock prop. I am, however, very curious about the Sharrow prop. I may bite the bullet and invest the $2K and see if it performs as advertised. It's a bit expensive, but if the numbers are as Sharrow says, with as much as we use the boat, it'll pay for itself within 2 years.

Still on the fence.
 
Whynot?":eqk8ttp0 said:
Hi Guys
Just bought a 2018 R23 with a 200 Yamaha. Great boat. Q. At WOT the RPM are close to 5800. Yamaha. 200 WOT range is between 4500 - 5500. I’d like to put a four Blade prop to help with following seas and holding the boat on plan and lower RPM. What do you think? What do you suggest?

THANKS
Chris
Why not?
Click to expand...

The recommended RPM for the F200 hp 2.8 L is 5000 to 6000 rpm making 200Hp at 5500. The rpm you are experiencing is spot on. Yamaha does make a good 4 blade prop that could help with stern lift. There are several other prop manufactures that make 4 blades that work well with boats used offshore to help maintain plane at lower rpm's. There is not a true science to this at least at our level (average boater) The best science that I have found is trial or talking to a good prop shop or service technician familiar with your boat or a boat with similar design. When I was working as a service technician and rigging a boat knowing the customers expectations and how they were going to use the boat determined what prop style I would install. If the customer was a first time boater and had general use expectations, the boat manufactures propeller recommendation was installed. My goal was to have the boat motor combination perform close to advertised with most emphasis on the WOT rpm of the engine. I always would shoot for the High end of the range to make sure the engine was never running in a over prop situation. I installed 4 blade props to achieve better hole shots, better stern lifting and reduced prop steering torque. I found that if the RPM range was good with the 3 blade I would drop 1" pitch with the 4 blade and the rpm would be very close to the same. Example 5800 with a 19P 3 blade = 5800 with a 18" 4 blade. That is not always true because prop design as to be taken into consideration too, Rake, cup and blade design and blade surface area. I will caution some boat designs are what they are and no matter what prop you throw at it the only thing that changes is rpm and speed for better or worse and the boats handling attitude doesn't change. If you want to try a 4 blade look into offshore design that advertises stern lifting and stay away from rake design props. Good luck !
 
SgtAlf":18kq7lny said:
Brian Brown,
What is an "over prop situation?"
Thanks,
Click to expand...

Over propped is when the engine is not capable of turning manufactures recommended WOT rpm range. When propping it is advisable to prop the engine so that it can turn in the upper end of the rpm range when equipped for normal use. When doing this if there is added weight from additional passengers, gear and supplies the engine will still maintain operation within Manufactures recommendation Example (1): normal load, full fuel, full water, normal passengers the wot rpm is 5700 rpm this is good, now add 2 more passengers an extra cooler sea conditions are marginal with 2' swells WOT rpm dropped to 5300. The engine is still operating in the manufactures range. Although it is close to the bottom end of the range Yamaha states it is acceptable. Same boat, loaded the same way as example (1) equipped with a prop with 2" addition pitch WOT 5400 rpm used in the same conditions would only turn 4900 rpm. This would be what I call an " over prop situation" The engine is loaded to the point it will not turn manufactures recommended WOT rpm of 5000 to 6000 rpm. Most people do not operate at WOT. The WOT recommendation is a way to confirm you are propped according to manufactures recommendation and the engine is loaded properly.
 
Hi Brian
Great explanations. Thank you. This weekend I was out in 5 ft following sea with a chop! Boat performed very well. Quite comfortable. She handled very well on the front side of the swell with a little trim tab adjustment.
But had to close the top hatches! Actually had a 27 Grady White following us in. Lol.

But I would stall out on the back side of the chop and had to add a fair amount of rpms to climb up over the swells. Current prop is a Yamaha reliance 14.5 x14. WOT average 5800 and 6000 when super flat.
My .goal is get on plane at 3600 to 4000 (16 to 18 kt) And give that added push with out having to go to full throttle to get up over those big one’s.
I’m looking at a Solas 4 blade 14.5 x 14. It should cap out at 5700 to 5800. Does anyone know if Solas is compatible with the Yamaha SDS system?

FYI Over propping to your motor is like driving around town with your parking brake on. Very bad to be on the lower end of that WOT scale.

Thanks again for your thoughts and advise

Chris
 
Chris, I'm not sure Solas makes a 14 pitch prop. Most of their props run 15P +. I recommend talking to them direct or to a Prop supplier for recommendations. Or go to a good prop shop have them recommend an alternative to what you are running. I'm going to guess the planning characteristics and the engines peak torque would probably align around 4300 rpm. You need a prop that has good stern lift qualities for midrange power to hold the boat on plane. Honestly that is a lot of boat for a 200 hp to keep on plane in big trough swells. You may be better off keeping what you are running now and using throttle adjustments when cruising in the New England sea conditions. I t takes a lot of power to hold a boat on a steady cruise in larger sea's.
 
Hi Brian
Thanks for the suggestions. I’ll keep the post updated if I make any changes.

Safe travels.
 
Hello

Yes we finally got it in on Nov 10. Made a very sizable difference. Whole shot was better. Now able to stay on plan at 17kt vs 21. Limited trim tab. Swells were not to big 2 ft. But had no trouble maintaining forward motion going up the back side of the swell. Overall I highly recommend the changeover. PT Propeller item #OFS412P. 15.25 X12 4 blade. engine WOT I maintain 6000 rpm. Top speed dropped from 36 mph to 32 mph.

I will still add trim tab drop fins in the Spring. Very easy. If you call Power tech Propeller as for Jeff

Good luck
 
Whynot?":spf7kc82 said:
Hello

Yes we finally got it in on Nov 10. Made a very sizable difference. Whole shot was better. Now able to stay on plan at 17kt vs 21. Limited trim tab. Swells were not to big 2 ft. But had no trouble maintaining forward motion going up the back side of the swell. Overall I highly recommend the changeover. PT Propeller item #OFS412P. 15.25 X12 4 blade. engine WOT I maintain 6000 rpm. Top speed dropped from 36 mph to 32 mph.

I will still add trim tab drop fins in the Spring. Very easy. If you call Power tech Propeller as for Jeff

Good luck
Click to expand...

Unfortunately reducing pitch reduces top end but who operates at top end. Prop the boat so it can maintain max rpm suggested by the engine manufacture and operate properly in the waters that you cruise in. A Tug owner that cruises in calm sea's will not need to compromise top end. A Ranger owner that cruises in the Cape Code Bay Area or ocean waters will get caught in those steep troughs and need that extra power when cruising in disturbed waters. Think of it as dropping a gear when climbing a steep hill. I would rather have the extra power and lift in the midrange then the top end. Boat manufactures give it all at the top end for marketing how fast the boat will go. I believe you made a good choice. The drop fins will add to the equation.
 
Hello,

Great thread!

I don't see info. on what prop you ended up with. Please post the details.

Thanks!
 
Whynot?":jweflz11 said:
PT Propeller item #OFS412P. 15.25 X12 4 blade.
Click to expand...

Power Tech OFS4-Blade Offshore Propeller has a constant 15.25 inch diameter regardless of pitch, available in every inch of pitch from 12-28. It has a polished finish, right or left hand rotation, moderately high rake, full tip cup for excellent lift, grip, comparable to Mercury Mirage/Yamaha Salt-Water series and available at No Extra Charge with the cushion lok hub design already installed to prevent hub failure. It is excellent for V-bottom Off-Shore style boats; single/twin/triple and stern drive applications.
 
Oops! There it is. My mask must have fogged up my glasses. :geek:
 
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