Speed for Sea Nymph 1648 w/ new Suzuki df25

[Mattsmall1972]

I just hung a new Suzuki 25hp 4-stroke on my older 1648 Sea Nymph. I am seeing 23mph top end without trim. Does that seem right or slow?

 

[Weldorthemagnificent]

Depends on weight and distribution. How many batteries, are there decks, how big a fella are you, and how many of you?
For example, my 16' vee Hull with a Johnny 35 with a 13 pitch prop will do an easy 30 with me in it and a rock to hold the bow down. Add a trolling motor, a battery, fishing gear my porky fishing buddy and I'm down to 26 add a third dude our size and down to 23 if I'm lucky.

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[Mattsmall1972]

I had an old Evinrude 35 and it felt like thw boat could fly. I just redid the boat - new floors and foam but no trolling motor and just one battery.

Honestly it seems quick enough for what I need to do but I am doing comparisons with other stated speeds and 23 seems slightly low. I am not sure if I am chasing a ghost.

 

[Sinkingfast]

Ya need to find the wot rpm...otherwise its like a one equation with two unknowns.


The Suzsucki 25 will not be close against that 35...

 

[turbotodd]

28 is all we could ever muster out of the one we were "tuning". Basic war eagle 544 w/ new suzuki DF25 on a PT35. After propping changes of course. I loved the idle quality but it seemed like it was underpowered for a 25.

My hull is not quite as efficient, yet 4 mph faster, also with a 25 on a PT35 (but yamaha and not suzuki). I almost bought a suzuki before I got this yamaha. I'd have been fine with a few MPH slower, but the holeshot difference I wouldn't have been fine with. The suzuki just feels like it's held back or something? Weird.

 

[Weldorthemagnificent]

Like stated, a tach is important to know where you are in your rpm range. Motor height is something you can play with and will often net an mph or 2.

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[MrGiggles]

I think you're right in the ballpark. Might be able to squeeze a couple more MPH out of it by playing with props and motor height.

I had a 1448 Alumacraft with a 25 Johnson. It would do 28, needed a hydrofoil to keep the nose down.

 

[jasper60103]

I just hung a new Suzuki 25hp 4-stroke on my older 1648 Sea Nymph. I am seeing 23mph top end without trim. Does that seem right or slow?

I agree with others have said. There are other factors to consider. I have a df30 on a tracker grizzly 1648 tiller. And that thing is a tank. I just hung it on and went fishing. WOT feels scary fast in my opinion. That said, you’re probably in the ballpark.


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[Mattsmall1972]

I went up a hole on Sunday and got another 1mph out of it. I spoke to a prop expert who said I was slightly overpropped but it wasn’t anything to worry about.

My readings were 23.0@5375 and 24.0@5500 with the 9.75x10 stock prop and 2.09:1 gear ratio.

 

[Weldorthemagnificent]

You're right in the ballpark. On the Suzuki website it states the standard prop as being 9.25X10. might give you a couple more rpm closer to the 6000 top limit and a little better holeshot. Sometimes going down a pitch results in a small increase in top end but probably not worthwhile unless you plan to run most of the time with a heavier load than when you tested. Not sure what you have in your boat as far as weight, but where you distribute it can make a difference. For example, yesterday I was testing an old motor yesterday with my daughter and I picked up one mph just by having her move from the front bench to the middle. If the motor isn't bolted to the transom, try shimming it up 1/2" at a time until it cavitates and then back down to the next lower position. (I assume you saying you went up a hole was referring to trim position). That may net you a small gain as well. Honestly, 24 isn't bad for a fishing boat and the quiet ride, fuel economy and lack of smoke should overshadow too speed.

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