Prop size

Wayne brown

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I have a Bennington 25 QX with a mercury 400 verado I have tried 3 different props all stainless a 3 blade 15 pitch a 3 blade 17 pitch and a 4 blade 19 pitch but basically on difference in rpm or speed running 6000 rpm and 45 mph 3/4 tank of fuel and 1 person seems like Iit would be different with each prop I’m thinking it should go about 50 mph with that motor maybe not but that’s why I went with that motor any suggestions on what or if anything is wrong thanks
 

Dgj

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May be motor mounting issue if your rpms didn’t change going from the 15 to 17. Were the 3 blades same brand and diameter? What brand and model props were you trying? Big heavy boat that rides good. But I agree it should be close to 50
 

Wayne brown

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They put a revolution 4 blade 19 pitch prop on delivery of the new boat to get buy they ordered me a solas rubex e3x15 3/4 x15rx and a solas e3x15 1/2x17rx and hardly no change in rpm or speed maybe 50 rpms if you have any information it would be appreciated
 

goldnrod24

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You are missing a key piece of info here. What is the max RPM of your motor? You say you are hitting 6000, but what is it rated to spin?
 

Dgj

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Get a mercury enertia in 15p and start there. It will probably have you close to 50. Where are you located?
 

Dgj

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Little far for me to help in loaning a prop.
I’m sure Solas is a fine prop But I would think that some one at the dealership would know that enertia is typically the best choice for a tri toon. Especially with a mercury.
Tell them you are not happy with the performance and if they keep trying to push solas challenge them and have them provide you with an enertia. I would stay in the 15 16 or 17 pitch non eco model to start with. Shouldbe able to feel the boat lift more all so.
 

Wayne brown

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Thank you so much for the information you are the best help I’ve had with this problem I’m calling the dealership now and will let you know the outcome thanks again
 

DejaWiz

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Not sure if this'll help, but you can narrow down your choices based on these recommendations as well as which ones you have already tried:


Merc400props.png


Good luck, and please keep us posted on any future results!
 

Dgj

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Do you have the cladded arch? And what seating and windshield arrangement do you have?
Glad to help.
 

Potomacbassin’

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Not sure when the dealer ordered these props but MANY of the popular and better performing props are very backordered. Talked to Ken at Propgods and he said some of the foundries had to shutdown due to Covid - combine that with boat sales going through the roof and there is just a shortage of everything right now. I was lucky to get my Q3 / Enertia as he had connections and knew of a guy in Tampa that had 2 left.

My guess is the Solas props were what was available so that’s what you got. But the dealer owes you a correct prop so keep pushing - even if it takes a few months. Everyone is feeling the pinch.
 

Wayne brown

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Do you have the cladded arch? And what seating and windshield arrangement do you have?
Glad to help.
I do have a arch and a windshield it’s got the swing back the results I got was with one person and a half a tank of fuel and thank you so much for the help
 

Vikingstaff

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I would echo everything Dgi has said. Absolutely need to try the normal enertia prop. They preform GREAT in general, and shine when paired with the Mercury outboards. I think it will be the difference maker. Just a matter of being able to get your hands on them, and then dialing in which size/pitch is optimal in getting you up to 6800 RPM at WOT with the boat lightly loaded with weight and fuel. With your boat, I would not bother with any other prop.
 

Potomacbassin’

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Yeah that’s a heavy boat. Here is a performance bulletin by Yamaha with a 425 in it getting 50mph, so I would imagine the 400 should be able to get close. Although is the 400 the supercharged 6? Not sure of the TQ output versus a V8.

Prop in the test appears to have some serious diameter which I’m guessing is to handle the weight of the boat. If you do some slip calculations that may give you some clues about what direction to go. There are props made specifically for heavier boats so make sure you give those a try as well (Mirage Plus, ECO, etc) although the Enertia will probably be a top choice if top speed is a priority. You may want to reach out to Bennington direct for their prop recommendation and contact Ken at Propgods who has a ton of knowledge.

It’s a tough time to test props due to shortages but that’s the best way to get it dialed in. Once you do you’ll be happy with the results.

359CEC88-6AA8-4ED9-9D59-4E52781B9624.jpeg
 
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