CONTINUOUSWAVE

Q1: can the acceleration onto plane of a 2012 170 DAUNTLESS with a 2012 Mercury 90 FourStroke be improved if the propeller is changed to a Mercury TROPHYplus four-bladed 17-pitch instead of a the present propeller, a Mercury LASER II three-bladed 19-pitch?

Q2: what other propeller change could improve acceleration onto plane when towing tubes or wakeboards?

BACKSTORY
I recently purchased a 2012 Dauntless 170 with the original Laser II 3 blade 19 pitch propeller and original 2012 Mercury four stroke. The engine already has a foil appendage extending the Anti-Ventilation plate aft. When pulling tubes or wakeboards the boat has trouble getting onto plane. The maximum rated horsepower is 90-HP.

I would like to try a four-blade Mercury TROPHYplus 17 pitch propeller to try to help the boat accelerate onto plane when pulling tubes or wakeboards.

I suspect you may never achieve the performance want from your 17 with a 90 HP four stroke engine. A 115 HP engine would be more appropriate for your boat. A four blade propeller of the right design should be very helpful. Removing the hydrofoil and ensuring the engine is mounted at the optimum height should also help performance. Proper engine trim will always provide better performance. The Trophy propeller you mention is a good candidate. If your local propeller dealer will allow you to try one out take advantage of the opportunity.

Reducing propeller pitch to 17 from 19 will improve the boat's performance accelerating onto plane when under greater loading. But working in the opposing direction, increasing to four-blades from three-blades will tend to increase the propeller load on the engine from the additional blade.

If you can obtain the TROPLYplus propeller on a trial-basis, it would be worth testing it, before you invest probably $500 or more in buying it.

Jefecinco- Copy all on the performance problems with a 90 on this boat. Unfortunately the max HP on the data sticker is 90HP. I never thought about the hydrofoil being a problem... Is the assumption that it is causing too much drag? I pulled the trigger on a used Trophy plus 4 blade 17P. I will report back what I find. Thank you.

Jimh- That is my concern as well with the added drag of the 4th blade. I guess I'll find out in a couple weeks when the prop arrives. Going out next weekend to get some baseline numbers on time to plane. Thank you for the insight.