87 Bayliner Prop question

[BAMORY]

Hey everyone, love this forum, so much info, I thought I would give it a try and see If anyone could help me out.

I have a 1987 Bayliner Trophy 21 foot hard top with 3.0 OMC Motor and outdrive, model # for out drive is 983841 (seriously underpowered I know, but its all mine) I recently hit an obstruction in 7 foot of water in Lake Erie Bay, toasted my prop and about an inch of skeg, limped it back to dock, all is repairable by me but here is my question.

The prop that was destroyed was a 13 3/4 x 15......and my extra prob that was in the boat is a 14 x 13, what is the right one. Yes i can put the same prop on that was destroyed, but I am curious whether either of these props were right for the boat anyhow.

Little more info

Redline is around 6000 rpm, but rarely operate above 4800 when tach is working. Boat is heavy of course, with a deep -V-.

Any suggestions on the most efficient prop choice will be appreciated...

Bruce

 

[steelespike]

Re: 87 Bayliner Prop question

You need to know what the max rpm and speed ran with your 15 ;seeing that is what you have been running.You need to know your motors max rpm rating probably about 4,800 sometimes on a label on the motor.You absolutely need a working accurate tach before making any prop changes.Also is very helpful to have an accurate speed,gps is ideal.How was the overall performance with the 15.Thats a lot of boat for a 3.0.
hwsiii has a program for prop selection. If you read some of his posts you will see the list of info he needs.Can be very helpful.

 

[BAMORY]

Re: 87 Bayliner Prop question

Max listed RPM is 4200-4600, performance was ok, max speed was about 27- 30 on smooth bay, I added a hydrofoil which really helped this boat get up on plane, lets just say that the boat would pull a wakeboarder with no problems, but no huge wake, but good for playing. I am just curious If going to a 13.75 x 17 will make that big of a difference. Thanks for the heads up and anyone else feel free to chime in

Bruce

 

[BAMORY]

Re: 87 Bayliner Prop question

I just talked with 2 different Bayliner dealers, believe it or not, the stock prop according to them that came with the boat and is Bayliner recommended is the 14 x 13, and both recommended that I try using each one of these to find out which one I like the best.

The 14 x 13 will increase my RPM by about 400, better out of the hole and on plane, but sacrifice some top end, the 13 3/4 x 15 will give less out of hole but increase top end a little according to both dealers I spoke with. Does this sound right? Really can make your head spin thinking about it.

Bruce

 

[BAMORY]

Re: 87 Bayliner Prop question

Ok prop update, put the 14x13 prop on and tooled around the lake, this is after I added an aftermarket tach that I knew worked, I was running 4400-4500 rpm's WOT, and speed was good. My WOT range is 4200-4600, so the 14x13 prop was the best bet for this boat. I will replace the 13.5 x 15 as a spare but very happy with the 14x13, it was just me on the boat so this could change with 3 other people

 

[hwsiii]

Re: 87 Bayliner Prop question

You didn't mention a speed to go with that and if it is GPS speed.


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