Stainless Prop 3 or 4 Blade ??

Blue Seaduction · 02-09-2009, 02:40 PM

I'm looking to up grade from the black Stainless on my 21' 06 Seahawk with the Yamaha 150.

Has anyone tried a four blade stainless ??

Starfish · 02-09-2009, 06:02 PM

I've run both 3-blade and 4-blade stainless props. IMHO it really depends on the specific prop and on what kind of application you're using it for. For my purposes the 3-blade gave a little better performance. In my current ase both were merc props (Tempest Plus and Trophy) but in general 4-blade props sometimes give a little better hole shot and rough water handling capability, while 3-blade props often give a little better top speed. In my case the Tempest gave better performance all the way through the range, likely because of better bow lift capability and huge blade surface area. My favorite prop was a Tempest that I sent back to a shop in Wisconsin and had them add additional cupping and sharpening... that was an awesome performer but my wife ran it aground while pulling me on a waterski and I haven't sent the new one back there yet.

In general those Yamaha stainless props like the one you already have are pretty darn good ones. I ran a polished 3-blade for years and loved it.

Before making any upgrades be sure to make a good list of exactly what characteristic you're looking to improve, as well as what your current performance statistics are. WOT RPMs and top speed empty and fully loaded, hole shot performance, porpoising, minimum planing cruise speed and RPMs, and cornering are all variables from prop to prop and even among different models of 3-blade props. Any shop you're working with will need to know at least the WOT RPMs and any specific goals before they can help you. Also take note of what hole your motor is mounted in and where your cavitation plate is relative to the bottom of the hull. In my experience most boat manufacturers mount engines lower on the hull than optimum, so you may be able to improve performance a bit just by raising the engine a hole or two.

You can temper all this advice with the knowledge that I'm not a mechanic, not a dealer, and just like to tinker with my boats...strictly an amateur. Find a reputable shop and they'll be able to give you a lot more specific advice. Don't be afraid to talk to some shops in the midwest or east coast... folks back there seem to put a bit more effort into getting the most performance out of their rigs than we do in the northwest.

Have fun!

tomictime · 02-09-2009, 06:16 PM

I have both a SS satwater series II 3 blade and a merc tempest 4 blade. for MPG and speed the 3 blade wins hands down - some 10% better on MPG, which at $6 a gal for marine gas where I boat - is a BIG deal.
The 4 blade is awesome at staying connected in rough water and if gas keeps droppoing will be my prop this season.

Starfish · 02-09-2009, 07:16 PM

Quote:

Originally Posted by tomictime

I have both a SS satwater series II 3 blade and a merc tempest 4 blade. for MPG and speed the 3 blade wins hands down - some 10% better on MPG, which at $6 a gal for marine gas where I boat - is a BIG deal.
The 4 blade is awesome at staying connected in rough water and if gas keeps droppoing will be my prop this season.

Tempest is a 3-blade, Trophy is a 4-blade. I've never seen a 4-blade Tempest. There's a 4-blade that is very similar in blade design to the Tempest that is called a Revolution 4, which I've always wanted to try. And then there's a 5-blade, High Five, which looks really cool and would probably be really fun in rough water.

Mooch · 02-09-2009, 07:27 PM

Quote:

Originally Posted by Starfish

Tempest is a 3-blade, Trophy is a 4-blade. I've never seen a 4-blade Tempest. There's a 4-blade that is very similar in blade design to the Tempest that is called a Revolution 4, which I've always wanted to try. And then there's a 5-blade, High Five, which looks really cool and would probably be really fun in rough water.

I run 3 bladed props. Like was mentioned the 3 bladed props are more fuel efficient in my application.

My father in law bought a High 5 for his Merc. He is convinced its faster than a 3 blade. I've tried to explain the extra drag associated with 2 extra blades,but he doesn't buy it. I want to say his prop was about $500. That might explain his reluctance to believe its actually a slower prop.

lurking_out_loud · 02-10-2009, 07:17 AM

I just tried a Yamaha SWSII on my boat and found several things that made me switch back to the older 21M and black stainless 21T prop.

1) I lost 1000rpm at WOT with the SWSII prop. It was also a 21T pitch but the increased cupping knocked me out of the correct rpm range.

2) Porposing came back. My boat was working flawlessly with zero porposing issues with the other props. My guess is that the increased cupping lead to less slipping which picked the bow up which caused the porposing. Switching back to the black stainless, no issues.

3) 3.85mph at idle. The slowest boat speed I could get without bumping in an out of gear was faster than the harbor allowed. Not good.

4) Fuel consumption was increased by half.

I'd suggest trying several different props to get it right with the boat. I figured that there wouldn't be much difference in the same manufacturers wheels with the same pitch. What I didn't realize was the impact different cupping would make on the boat. In my case, it was huge. Good luck.

-lol

Mooch · 02-10-2009, 03:55 PM

Quote:

Originally Posted by lurking_out_loud

I just tried a Yamaha SWSII on my boat and found several things that made me switch back to the older 21M and black stainless 21T prop.

1) I lost 1000rpm at WOT with the SWSII prop. It was also a 21T pitch but the increased cupping knocked me out of the correct rpm range.

2) Porposing came back. My boat was working flawlessly with zero porposing issues with the other props. My guess is that the increased cupping lead to less slipping which picked the bow up which caused the porposing. Switching back to the black stainless, no issues.

3) 3.85mph at idle. The slowest boat speed I could get without bumping in an out of gear was faster than the harbor allowed. Not good.

4) Fuel consumption was increased by half.

I'd suggest trying several different props to get it right with the boat. I figured that there wouldn't be much difference in the same manufacturers wheels with the same pitch. What I didn't realize was the impact different cupping would make on the boat. In my case, it was huge. Good luck.

-lol

The SWS II props are huge.

I tried a 17" pitched one on my F150 and couldn't hit more than about 5200 RPM. With a Black SS Yamaha pitched the same I run up about 5900.

The SWS was given to me. It didn't work so I sold it for $300.

micropeterous · 02-10-2009, 04:53 PM

Quote:

Originally Posted by Blue Seaduction

I'm looking to up grade from the black Stainless on my 21' 06 Seahawk with the Yamaha 150.

Has anyone tried a four blade stainless ??

You might try contacting Propcopropellers.com in Monroe, Georgia. Several years ago I gave them the pitch and diameter of a prop I wanted for a bass boat. The prop I got from them was very fast and I couldn't drive the boat through the chine walk I was getting. I called Propco and told them what the boat and engine combination were. The man on the phone laughed and said: "running a little fast for you is it?". I told him it was and he told me to send the prop back and they would bend it into something a little slower. I sent it back. They did what they said they would do and the prop worked out great. There was no charge on re-pitching the prop. I don't know if they are still a good company but they sure were when I dealt with them. My guess is that this company would be able to give you some pretty good advice.

Just-in-Time · 02-10-2009, 05:16 PM

www.propgods.com is the best in the east

tomictime · 02-10-2009, 07:29 PM

You are..right..sort of...i went and looked and my 4 blade is a Typhoon

Quote:

Originally Posted by Starfish

Tempest is a 3-blade, Trophy is a 4-blade. I've never seen a 4-blade Tempest. There's a 4-blade that is very similar in blade design to the Tempest that is called a Revolution 4, which I've always wanted to try. And then there's a 5-blade, High Five, which looks really cool and would probably be really fun in rough water.

Starfish · 02-10-2009, 08:07 PM

Quote:

Originally Posted by Mooch

My father in law bought a High 5 for his Merc. He is convinced its faster than a 3 blade. I've tried to explain the extra drag associated with 2 extra blades,but he doesn't buy it. I want to say his prop was about $500. That might explain his reluctance to believe its actually a slower prop.

Your F.I.L. might actually be right depending on his setup... I've heard some good things about the top end on High Fives, sometimes rivalling three-blades. For one thing you can raise the engine a bit higher on the transom which gives less drag. The one big drawback is that they have very poor reverse thrust, which can be a surprise the first time you come coasting in to the dock and try to put on the brakes.

Quote:

Originally Posted by lurking_out_loud

1) I lost 1000rpm at WOT with the SWSII prop. It was also a 21T pitch but the increased cupping knocked me out of the correct rpm range.

2) Porposing came back. My boat was working flawlessly with zero porposing issues with the other props. My guess is that the increased cupping lead to less slipping which picked the bow up which caused the porposing. Switching back to the black stainless, no issues.
-lol

The decreased RPM was likely from bigger surface area... I doubt if cupping alone would cause it. Cupping generally increases the "grip" of the prop, keeping it from blowing out and ventilating. That can let you raise the engine higher on the transom and again decrease drag and increase RPMs and speed.

Most porpoising problems are caused by props with less bow lift, not more bow lift. I seem to recall hearing that rake, not cup, causes increased bow lift. Rake can be different between different props of the same pitch and diameter depending on the make/model of the prop.

Blue Seaduction · 02-10-2009, 08:08 PM

Thanks for the input, I'm checking all options before I dish out the funds.

Mooch · 02-11-2009, 06:38 AM

Quote:

Originally Posted by Starfish

Your F.I.L. might actually be right depending on his setup... I've heard some good things about the top end on High Fives, sometimes rivalling three-blades. For one thing you can raise the engine a bit higher on the transom which gives less drag. The one big drawback is that they have very poor reverse thrust, which can be a surprise the first time you come coasting in to the dock and try to put on the brakes.

I don't see a high five ever being faster than a quality 3 bladed prop. Maybe, on a light go fast rig like a bass boat,but not on a heavy deep vee boat like he runs. Mercury doesn't even recommended them for speed. They recommend them for waterpsorts where you need hole shot.

Jsteel · 02-11-2009, 09:03 AM

I've been very happy with my four blade on my 20 foot aluminum boat with a 90 hp motor -- but the biggest reason I've liked it has been mentioned above -- it really grabs and holds in rougher water. I really notice the difference on bouy 10, ocean salmon, and ocean tuna trips. I may be sacrificing some fuel economy, but I'm not planning on switching back anytime soon.