Post 42 Sportfish Hi Pitched turbo whistle

I found that the sound was emanating from the engine room access door and hatch, which made perfect sense. However, when I covered certain areas of the door seams with my hands it seemed to change.

It that air getting drawn into the E R? Sound go away when the hatch was opened?
It's been a while but I have been on air starved boats.

If the noise is coming out of the engine room, it is probably not starved for air as it would be sucking air in and noise wouldn't be coming out so much. But yes, try to open the engine room door at cruise rpm and see if there is any suction on it. If not, gasket the engine room door better. Yes, I have been on some SF where the turbo noise was unbearable at the helm....I ran a 32' cabo express from Fort Laud to Savannah and the mate and I had to wad up paper towels and put them in our ears and NO WAY to even hear each other yell at each other hardly.

My Ocean as the exact same motors. I have that whistle. I've gotten used to it but it is distinct. WOT for those motors is 2600 and cruise according to manual is 200 off, so.. 2400. I run my engines pretty easy at 2200 but I will say the whistle is less noticeable as you get closer to 2400 rpm. My engine room door could use better gasketing as well, just haven't gotten around to it.

I have no comment on the turbo noise but are you sure you were cruising at 31 MPH (27 knots)? That seems awfully fast for that boat from what I've read.

The sound and sounds that we can't hear (Our 4 legged friends can) are different.
If dawgs are a part of your usual cruises, then bring the bud along for a ride. Watch him and try to draw from his behavior if he's (she) is comfortable.
It's not a fun boat if all of the family is not having fun.

Josie and I luv da puppies (like grand kids,, they go home), we cruise with kats.
All are happy till the beam rolls.
Tiger still gets S Sick on the beam rolls.
Josie still won't let me get stabilizers,,, for da kat.

I have a 99 with the TAMD 73P's (A little less HP and torque than the 74's). You definitely know when the turbos are spooling (around 1600 RPM). My boat was stripped pained and has all new gaskets, and there is nothing that will mute the sound. You do however get used to it. I cruise around 2250 fully loaded bait ice fuel ect and run a consistent 25 knots in a 1-3 ft sea with equates to 28.75 MPH. So the boat is running to spec.

We almost bought one a few years ago, cruise speed was one of my concerns as I was told 20 knots.....guess I should have done some more research!

My bother has Volvo's in his boat, slightly different model than these, and he has loud turbo whine as well. Assuming it is normal for these motors? I guess all you can do is improve the sound insulation to tone it down.

Is there a turbo wrap and air in silencer for these rigs?
Remember the original air silencers for the Detroits? Size of a skinny trash can with a foam end covers.

Mine Tops out at 31 Knots at the governed 2600 RPM. I did however shed some useless weight, like gelcoat, washer dryer ect.

The Volvo's are pretty fuel efficient. 31 to 33 gph at 2250.

How did you shed weight from gelcoat? Stripped it?

Gel Coat was stripped down to glass (the whole boat) the boat was epoxy primed then Sprayed. This was done just before I purchased the boat.. 6 years later it has held up great...

Interesting. This must have been one of the boats with the gel coat problem. Did Post do the work?

Gelcoat Problem, Yes... The work was done in Maryland on the Chesapeake before I purchased the boat. Was not completed by post.