What engine for fast quiet ride?
 

I have a smuggler 245 s with à penta 5.0 Gsi 250hp and penta DPS drive.
WOT give about 53 mph at 4800rpm.
The problem is that I want to Cruise at that speed but its too much noise.
Do you think a change of engine and drive to a penta dpx 500 with dpx drive would be more quiet in the same speed.
I think top speed with that engine (500 hp) Will be around 70 mph.
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If anyone have experiance from installing bb instead of sb I would really like to her if the boat got more quiet.
Sorry for my poor english, I am from Sweden

Both will be equally loud.

Even with lower rpm at same speed?

I disagree at lower rpm any engine will make less noise, is there any way to add soundproofing to the motor compartment? Obviously you will want to have thru prop exhaust with either option if you want it quiet. Don't forget you also have a substantial amount of wind noise at that speed. Where in Sweden are you? I have a few clients/ friends from Stockholm.

I think corsa or silent choice you can run up to 3500 rpm?

You can ask the same question on our more local Swedish forum, www.boatsite.se, and you will most likely get some answers there as well.

Tomas

I'm in Gävle 170km north of stockholm.
And yes I will put a lot of soundproofing materials in the motor compartment. A company called Karnag sells stuff for that purpose and they say that I can expect 10dB reduced sound. That sounds good to me.

I will try there to.
Thanks for your answers.

Had two friends with the same boat. One was small block powered the other had a big block. The big block boat was much louder. The owner of that boat ended up buying Silent Choice.

Hello
About time I update this thread.
I changed to a penta 8,1 GI 375 hp.
With F9 props, the old where F6.
Now Max speed is 65mph at 4600 rpm
And it is much more quiet at all speeds.
I did install karnag's soundabsorbing material.

Bigger motor will probably have too much backpressure running thru prop, especially at 500+ HP. Best bet is to go thru-hull and utilize a set of turn-downs to get the exhaust to exit below the water line. As mentioned, maybe add some additional insulation in the engine compartment to lessen mechanical noise. But make sure the engine can still get enough air.