1999 OUTRAGE 17 Propeller Suggestions

[eriedeary]

Q1: will a stainless prop Turbo 1K make a difference in performance on my boat as described in the narrative below?

Q2: what other propeller is recommended?

I realize [that rigging a particular propeller will have some] give-and-take [outcomes].

I am generally happy [with the] overall performance [of the boat], but I would like more "gun-and-run" torque to get over "it" in sloppy conditions. With a light load the current time to plane from a stop is five seconds.


BACK STORY
In 2018 I re-powered [a 1990 OUTRAGE 17 with a] 2012 Yamaha F115, replacing a Mercury 135-HP OptiMax.

The positive effects were:

• weight on the transom was reduced about 40-lbs, resulting in the deck drains being above the static waterline (which is important to me because I need the boat to be self-draining as it is kept at a dock that is one-hour distant;
• the Yamaha engine improved the [fuel] efficiency [compared to the Optimax];
• the Yamaha engine reduced engine noise [compared to the OptiMax];
• the Yamaha engine reduced the need to clean the spark plugs [as often as was needed on the OptiMax]; and,
• the Yamaha produced a "great" trolling speed.

The boat performance with the Yamaha F115 with a Yamaha [aluminum three-bladed] K-series 13.25-inch x 17-pitch propeller [of unspecified number of blades and unspecified material and later clarified to be an aluminum propeller with three blades], with 28-gallons of fuel, just me aboard and light gear (260-lbs), and in a river with flat sea state is as follows:

• idle engine of 700-RPM produces 2.5-MPH boat speed;
• at full throttle engine speed is 5,400 to 5,500-RPM and boat speed is 33 to 34-MPH;
• [estimated] total boat weight is 1,750-lbs, engine weight is 410-lbs;
• fuel tank held 28-gallons.

[When trim-out is kept limited] the engine speed peaks at 5,800-RPM.The propeller [ventilates] when the trim-out is increased, and engine speed increases to 6,000-RPM or higher from 5,800-RPM.

In the past. on open water, with a heavier load (related to more fuel, more people, more gear), ]the engine] would never "rev out " [perhaps means the engine speed would not hit the rev-limiter], likely because I would never go that fast [that is, I would advance the throttle to full].

Typically [speaking still about in the past still) I would [advance the throttle to get an] engine speed of about 4,000-RPM which resulted in a boat speed of "low twenties' [perhaps means somewhere in a range of 23 to 25-MPH].

However, when there is chop on the open lake, I would like better "hole" [perhaps means faster acceleration from a stop to on-plane boat speed] in order to get over "it" [perhaps the boat's own bow wave with attendant bow rise] with [perhaps means a heavier] load. But [when running] in chop [on an] open lake [I] would like better hole [again perhaps means faster time to reach plane from a standing start] to get over it [again, perhaps "it" mean bow rise] with [perhaps means a heavier] load.

I feel like I have some [engine speed] to give up at the [full throttle setting] because the propeller is spinning-out in optimal conditions when alone; and I never use [the upper engine speed range] in open water unless the sea state is flat.

[jimh]

If your goal is to improve the time-to-plane from a standing-start to be lower than five seconds, please give your expectations for how much faster you need the time to be. Also, please indicate how much you are willing to spend on a new propeller to achieve the desired reduction in time-to-plane.

Also, your other goal of reducing engine speed at full-throttle is going to tend to INCREASE the time to plane. Please clarify which of these two goals in import, because at the moment the two objective are unlikely to simultaneously be met by a change in propeller.

[eriedeary]

My goal is to [have] better performance with [a greater] load in "slop" [sea states].

I am shopping [for] value.

I understand give-and-take

[jimh]

Changing to a four-bladed steel propeller of 1-inch less pitch may improve the time to plane somewhat.

Generally a pitch reduction would tend to increase engine speed at full-throttle, but the change to a four-bladed propeller may tend to reduce engine speed at full throttle, and the two effects may cancel each other, resulting in no change in engine speed at full throttle or just a small change.

I cannot recommend a specific propeller because I have no idea what the gear case diameter on your engine might be. Often engines in the 115-HP range use a smaller diameter gear case, and the choice of propellers is somewhat limited compared to the choices available for engines of greater horsepower that use a larger diameter gear case.

The cost of a new stainless-steel polished propeller will be about $600. If want the best possible performance, you can specify that the propeller be further enhanced by balancing and matching, often a service provided by a specialist who works mostly with boat owners who are engaged in racing and want to get the most possible performance. You seem to be in that same realm, as you think changing the propeller will be able to produce the desired goal of faster time to reach plane.

You have not commented on how much improvement in the time to plane from the current five seconds you are seeking, but you may find that to get significant improvement--if at all possible to achieve--may mean you need a an expensive, carefully crafted propeller.

You now have three goals in mind for the new propeller to produce: faster time to plane, reduced full-throttle engine speed, and ability to do something better (and unspecified) with a certain load in certain sea states.

Generally the best way to improve time to plane is to have an engine with more horsepower and particularly more torque in the low-engine speed range. The engine you took off your boat, the Mercury six-cylinder two-stroke-power-cycle direct-injected OptiMax 135-HP engine which was essentially a de-rated 150-HP model, probably had all those characteristics compared to the replacement engine, a 115-HP four-cylinder four-stroke-power-cycle engine with natural air induction that was the highest rated horsepower in its family of engines with the same four-cylinders and displacement. Also, a larger displacement, six-cylinder, two-stroke-poewr-cycle engine would typically have excellent low-engine speed range torque.

I am not certain that you can get all the performance enhancements you want from the newer, lower horsepower, smaller displacement, fewer cylinder engine just by changing propellers.