Picked up a 89 311
 

So I ended up buying a 89 311 from a dealer that took ownership of it cause of overdue bills. Boat is in good shape..been sitting in rack storage untouched since 07. Ran compression numbers they are good. Boat only has 330 horse motors in it. Which will be changed sometime. I don't think it will even run 60 with them. Few questions....

Anyone have a cover they want to sell?

Anyone have pictures of the silent thunder mods to make it sound better...ways to quiet for me.

It has 23 mirage on it now...thinking I'm going to try some hydromotive 22 4 blades for more stern lift.

I need a trailer...anyone have or know of one laying around?

http://www.offshoreonly.com/forums/f...-platform.html

Here is a thread on my exhaust that I just did

How about some pics of the boat .

60/62 with 330's

anyone have pics of the silent thunder drilled out?

Do you mean the baffles at the tips of the platform ? If so just take a sawzall with a long blade and shove it in the hole and cut it out takes 10 min . Sounds louder if that's what you want and can still hear the radio !

Some guys drill holes in the bottom to allow water to drian out..

I had a 292 sr1 and I removed the baffles located within the silent thunder and removed the rubber flappers on the rectangular exhaust tips. On my 357 sr1, I did the same and also cut 6"/8" diameter holes under each exhaust port and then installed a plastic screw in inspection port. That way I could change the sound of the exhaust depending on where I was boating. IMHO, removing the baffles and cutting the holes in the bottom of the silent thunder did not jeopardize the structural integrity of the swim platform.

I opened up the swim platforms on 2 different Formulas, made no difference in performance just made the boats louder. The 3rd Formula I left alone. The best performing all around prop for my 311 was a Bravo 1 4 blade. It was only 1 mile an hour slower than a 3 blade mirage and the handling was much better.

What motors were in your boat? What pitch bravos??

I had stock 454 mags with full roller rockers and Gil Magnum Sport exhaust manifolds. The boat would run 64 mph @5000 pm with 24 pitch Bravo 1 props, and 66 mph @4600 rpm with 26 pitch bravo 1 props. So I used the 26's, and it would cruise 42mph @3000 rpm on my GPS.

I have a 1989 Trail-rite triple axle trailer for sale. It is a 15,000 pound steel trailer in Very Good Condition. It will carry 12, 882 pounds. Trailer has never been dipped into salt water. Drum surge brakes on two axles. Six new Duro tires with approximately 3,000 miles on them. The trailer has leaf spring suspension with straight axles. Rims are 14.5x6 with 6 lug pattern. The length from the bow roller to rear of trailer is 27’ and the winch post can be moved forward another couple of feet. 2-5/16” ball, 7 pin electrical connector. All lights works as they should. One keel roller needs to be replaced and the drop leg for the tongue jack is missing. The trailer was used to transport a Formula 292 SR1 from Arizona to Florida. $2500.

Already bought a trailer..

38 fountain. Do you have any pics of where you cut the holes ? Was it in the swim platform ? Or under the exhaust that comes out. Also matjluk so your saying just stick a long blade in the square exhaust tips as far as it will go & cut ??

I don't have any pics as it was a few boats ago, but I would first locate the baffle plate that is glued inside the exhaust chamber under each exhaust outlet and measure to a point outside of the platform. Then I would cut a circular hole in the bottom of the swim platform just bow of the baffle. I would cut a hole and install the largest removable inspection plate that you can. This way, you can tune your exhaust to the desired loudness you want and you don't have to cut the baffle plate. I also cut the baffle plate and removed the rubber flappers on the exhaust tips before I ended up cutting the holes. I used a paddle bit and drilled a series of holes around the perimeter of the baffle from the exhaust port, until I could punch it out with a hammer. It was pretty ugly, but got the job done and no one looks inside. I like the long blade method better though, cleaner cut. If you are going to remove the baffle and cut holes in the bottom, I would locate them as far away from the stern of the boat as possible, to decrease as much back pressure as possible. My buddy had a 311 with innovation marine engines (520+HP) and removing the platform altogether gained him 3-4 mph, if I recall. I don't think the silent thunder adversely impacts hp on sub 500 hp engines. Good luck.

Ok. Thanks for all the info. Very helpful. !