4 Blade SS props for 06 Gulfstream w/ twin 150s - Recommendations

[julesar]

Apologies if this thread has been duplicated elsewhere - but, I could’t find the answer I was looking for when searching this forum.

I am looking to see if anyone has replaced the 3 blade SS props on their twin Yamaha 150s on a 06 or greater Gulfstream to 4 bladed SS props, and if so, which ones (diameter and pitch) and how well do they work? I don’t care about top end, mostly about having better hole-shot and mid-range performance.

Thanks in advance and Happy Holidays to you all…..

 

[Mustang65fbk]

Grady White has some performance data on their website with a 232 Gulfstream and twin F150's on it, though the test does appear to have been done with 3 bladed props vs 4 blade. Click on the link, scroll halfway down, click on "performance", then select twin F150's for the motors and compare your stats with theirs. The propeller that they used was a "14 1/4 X 18 Reliance SDS" prop, which appears to be a 3 blade prop per the Yamaha website. In which case, you might compare it to the props you've currently got, as yours might not be the correct size/pitch for your particular application.

Grady-White | Gulfstream 232 Walkaround Cabin

Grady-White 23-foot walkaround Gulfstream 232 is a solid, safe, feature rich sportfisher that more than holds its own versus much bigger boats.

www.gradywhite.com

 

[Hookup1]

I have the exact setup you are asking about. Twin Yamaha F150's. 3-blade switch to 4-blade (2006). Different hull.

Below is a re-post of my experience switching props. I couldn't be happier. Game changing performance with no downside for me. It's more important to let the engine breath and not bog down thru the range you use your boat. Tuning your boat for top end speed that you almost never use is a testosterone thing. You may find out that you don't loose any top end speed.

I have been running a 268 Islander with twin Yamaha f-150's with 17 x 14 1/4 3-blade Yamaha Reliance stainless.

Generally the boat is a 10 knot or 20 knot boat with no in-between. I want to improve my low end performance so I can plane at lower speed. I have plenty of top end and can only use it on the best of days.

I spoke to Ken at propgods.com and he recommended swap for 15 x 14 4-blade. Thinks my low speed performance would significantly improve and maybe even my top end speed.

Propgods.com recommended these…

https://propgods.com/shop/ols/products/ptz4 (on order)
or these
https://propgods.com/shop/ols/products/ptz3 (similar to Yamaha Reliance)

So I've had my chance to test these props in the Florida Keys this winter. For my 1997 268 Islander w/twin F150's they are absolutely perfect. Dropped 2" of pitch, 1/4" of diameter and changed to a different style prop (vs Yamaha Reliance). Significant - unbelievable improvement in low and mid range performance. Boat will plow and plane at lower speeds that could not be done before. Top end unaffected. In rough seas motors don't bog down and "grip" better to keep boat from falling off. Highly recommend.

A lot of boaters think dropping pitch will slow the boat down. Not always true. If over propped and "slipping" its too much load on the engines. Prop correctly and increase efficiency.

I have been planning to write them down but its been so windy and rough. I'll do it this week. For me though it's more about how the boat feels in different sea conditions.

For example running in with a following sea was always a problem. You push the throttles up to a speed to match the waves behind you. Run along for a short while and the boat gets some air under it and runs away at 20 knots. It then crashes into a wave in front of the boat, boggs down the engines and you are back at 10 knots. Much different now. You can pick a speed either plowing or planning and the engines will hold RPM's. It's a easier ride instead of getting slammed around.

Also I ran offshore in a head sea. Easier to dial in a speed and the level of abuse you want to take. Holds RPM's much better.

I have run the motors up a few times when conditions permitted. The cruise and top end are still there. I'll get numbers up this week.

So here are the raw numbers from a Florida Bay run by Channel 5 East to West and reversed. Blowing 20 knots ESE. 150 gallons of fuel and 2 people on board. 15 gallon bait well with water on transom step. Lots of gear on boat.

Higher end performance is right in there with the old props. Low end performance much better. You could not plane at 3,400 RPM's. 3,900 RPM's was problematic.

 

[Peter A]

Ken @ prop gods gave me good recommendations for my hardtop F200 208. If you call or email Ken, the more information you have about how YOUR boat is performing such as min. planing speed and rpm, best cruise/rpm/fuel consumption, max speed/rpm/mpg with light and heavy load, motor height, any handling quirks, condition of bottom paint, intended use…he can make a better recommendation. I went with his suggestion of Powertech SCE4 14x14 which seemed to me not enough prop on paper but I am very pleased with the results. I don’t have the original reliance SDS 14.25x17p to compare but the performance all around much better versus a Solas HR4 14.5x15. I may still raise the engine one hole but probably not worth the effort for a couple of MPH top end.

 

[Sardinia306Bimini]

I had several kinds of 4 blades and some worked and some made it worse.
As suggested ask Ken from Propgod, he is usually spot on.
I had the PowerTech he suggested and they did not work at all on my Venture 34, but it was a pain to fnd the right propellers and i had to trie about 6 different kinds. However, a lot of boaters use the PowerTech's sucessfully and are happy with them.
I had a Solas Titan 4 blade on my dive rib and it worked well and one of the Powertechs on ymy dive panga and there it worked better than any 3 blade i tested on both boats.
The third and widely used one is the Mercury Revolution 4 what seems to give good results too.

To make the 4 blades turning still manufacturer recommened rpm's at wot there are two ways:
a) same pitch but considerable less prop diameter
b) similar diameter but generally spoken 2" less pitch
What of both is the better solution depend on boat, hull shape and engine torque

However, in most cases and coming from a correct working prop with low slip at WOT boat will use a few mph's top end speed but gain considerable mid range economy, lower planning speed and manoevreability. 4 blades can also rise trolling speed / lowering rpm's necessary what is at 6-8 knots not really a big gain but for high speed trolling it can be a big fuel economy gain as boat will troll 10/12 knots at lesser rpm's and 10-15 knots is a very uneconomic boat speed.

As i am absolutely not interested in top speed, but in fuel economy, grip and lower planning speed i prefer 4 blades over 3 blades.

Chris