228 Prop help needed

[Joe]

I've a got an '06 228 with a 3.3L F250. Boat has a hardtop, pulpit, two fuel tanks (main and aux), and no bottom paint. Engine runs great; Doesn't seem to be lacking power at all.

That said, it has a Yamaha SWS II 15 1/4" x 17" prop on it. At WOT throttle, with a full load (4 people 1.5 tanks of fuel), I am getting about 43 MPH, between 5900-6000 RPM. At WOT with just me and 1.5 tanks of fuel, I get about 43-44 MPH and its bumping off the rev limiter at 6K-6.1K rpm.

The Yamaha/Grady performance bulletin with the same boat and the 4.2L Yamaha F250 with the SDS version of the same prop is reported to go 48 MPH at 5800 RPM.

Should I move to a 18" or 19" of the SDS prop to get the same WOT speed? I was under the impression that the SWS II non SDS and non SWS II SDS props are the same except for the SDS dampener mechanism. Is there a difference in pitch or blade design between SDS and non SDS props that are stated to be the same diameter and pitch?

 

[Doc Stressor]

Your getting 18% propeller slip running 44 mph at 6K rpm. That's not right. I'd bet your engine is mounted too high.

My 226 goes 44 mph at 5700 rpm with the same engine and prop. That's without a bracket and a pretty heavy load.

 

[Parthery]

My prop slip calculator shows 9% at 6K RPM and 44 MPH. The 3.3 F250 has a 2:1 ratio gearcase...the others are 1.86:1

9% is actually pretty good. You might try a Mirage Plus to get a bit more lift and pick up a mile or two on the top end. Otherwise, I think you are dialed in pretty good.

For what it's worth, no 226/228 with a 3.3 F250 has ever gone 48 MPH except when it's on the trailer going down the highway. 43-44 is dead on.

 

[Grady_Crazy]

2005 228G F250 3.3L 4 Stroke with just me and 3/8 tank of fuel. Water tank empty. Speed per GPS.
4200 RPM 29 mph Cruise
6000 RPM 43 mph WOT

 

[Joe]

I really like the SDS props; I've used one before and love the quietness of it. I can't help but think using an 18" or 19" SWSII SDS prop may get me a few more MPH at WOT out of it without hurting "out of the hole" performance.

 

[lgusto]

Search this forum for my posts on "prop god". Those guys are the best resource for prop upgrades.

 

[Doc Stressor]

My prop slip calculator shows 9% at 6K RPM and 44 MPH.

You're right of course. As the consequence of my old age and senility, I misread that he was using a 19" prop. :sorry

 

[SmokyMtnGrady]

parthery is right. There is no way the 228 will do 48 on the water, unless maybe you are in the bay of fundy on an outgoing tide with a 20 knot wind to your back, then maybe it would.

I switched to a 4 blade prop and I turn 15.5 inch x 17 pitch wheel. I dont know jack about how to calculate the slip rate so I will leave that to Doc.

Here is what I do know by going to a 4 blade prop I have better hole shot which is critical in bass fishing tournements ( the 228 is the rave on the BASS pro fishing circuit) and water sports.

I can get on a plane at about 21 MPH which is a little slower speed.

I can turn better at speed which is good for evading the po-po or when towing a tube for water sports.

My cruise speed fuel economy improved by .10 to .20 mpg.

In following seas when returning to port I noticed better handeling in larger swells.

Since the 228 is a bracketed boat and folks say how difficult it is handle around the dock, I noticed better reverse performance too there.

I lost about 1 MPH at the top end. The boat all around handles better in my opinion with a 4 blade prop on her. I have the OEM SSII prop as a spare with complete prop kit on board in case something happens. I bought the prop online through the prop gods people as I recall. My only complaint is when we were in the Bahamas the water there turned the highly polished silver to a dull gray. When I returned to the states and ran it in freshwater it was silver again. I am not sure the grade of stainless they use, but other than that, I am glad I switched.

 

[Joe]

Odd that everyone says the boats won't do what the reports say. By the reports:

The 228 w 4.2l f225 = 44 MPH WOT
The 228 w 4.2l f250 = 48 MPH WOT
The 228 w 4.2l f300 = 50 MPH WOT

I know the 3.3L F250 and the 4.2L F250 are two different engines..but the 4.2L actually has a lower gear ratio, meaning it would have to turn MORE RPM's to get the same speed out of the same prop than mine. It actually turns less..and goes almost 5 mph faster doing it.

 

[Doc Stressor]

but the 4.2L actually has a lower gear ratio, meaning it would have to turn MORE RPM's to get the same speed out of the same prop than mine.

The 1.75:1 gear ratio of the 4.2 L engine means that it would turn LESS rpm to get the same speed with the same amount of slip relative to the 3.3 L with a 2:1 ration. The extra torque of the larger engine lets it swing a higher pitched prop.

 

[Joe]

You are correct; I stated the rpm backwards.

But...according to the Yamaha perf sheet on the boat the 4.2L is swinging the same size prop (15 1/2 x 17" SWS II SDS) and getting WOT of 5800 rpm at 48 MPH.

That engine must be a torque monster.

 

[SmokyMtnGrady]

It seems perhaps with the new motors top speed would increase. However, YOUR motor which is the same displacement as MY motor will not push your boat to 48. In a way it is meaningless to discuss a new motor on the same boat when one does not own the new bigger motor is it not? I would love to hang that 300 on my boat. That would be awesome. I am saying though you should seriously consider turning a 4 blade prop.

 

[Joe]

A four blade doesn't really do what I'm looking for though. I'd like to get a few more MPH top end. My "out of the hole" and loaded performance is fine for what I do.

 

[Doc Stressor]

Just out of curiosity, why are you interested in squeezing a few more mph out of the top end? A 228 is not a go fast boat. The hull really doesn't do very well in any kind of seas at speeds over ~30 mph. Do you keep your boat on a lake?

 

[Joe]

We do a lot of going to boat only accessible islands--most of those islands are accessed on smooth water ICW. Its anywhere from 15 to 20 miles via the ICW to get to and back from them.

 

[Joe]

Bringing this to the top...

Just bought a 14.25x 18" Salt Water Series II SDS prop for my 228. From the very small amount of testing I have done (literally less than 3 miles) I gained about 2-3 MPH on top end, still saw about 5900-6K RPM at WOT (by myself, 1/2 of both tanks of fuel) and lost nothing out of the hole. Also got rid of some prop chatter shifting into gear and when riding with a strong current.

I'll give a better review when I get some more time on it, but it looks like this prop was exactly what i was looking for.

 

[SmokyMtnGrady]

I am just getting back from my kids 8th grade trip to the Charleston area. We went to Isle of Palms and took a boat tour to the north there. Nice area. Did you get your prop issue resolved?

 

[Joe]

SmokyMtnGrady-

Thanks for the follow up. Lots of visitors to CHS for the next few months! Definitely a great place to be this time of year.

Not sure if you saw my post above--looks like the Yamaha SWS II SDS 15 1/4 x 18 is the trick, at least for me and my setup. Haven't got to test it any more since initial install, but unless its different than what I see--I'm saying this is a win.

 

[Joe]

Last update on the prop:

Tested last week with 4 adults and 3/4 tank (main tank) of gas. Aux tank was only showing two bars. 45-46 MPH WOT according to the GPS with hardtop curtains on (front window zipped down in the middle) bouncing between 5900 and 6000 rpm. Water temp 75 degrees, light wind (5 mph or so) against me. 2.1-2.3 MPG at ~21 GPH from Command Link gauges. Might be a little slower out of the hole, but it never was a speed demon.Tabs make it plain faster.

VERY happy with this prop!