Opinions and advice

[betroncm]

Ok you guys are probably sick of answering prop questions but after reading a hundred post I'm still not sure if if I have the right setup. I am very new to boating so I just want to make sure I have the right gear. I have a 86 Bayliner 19.5 ft. with a 350 V8 and a volvo 275 outdrive. I have no idea what the gear ratio is or where to find it. I took the boat out yesterday and felt the boat had plenty of power and accelaration. Unfortunately I was hesitant to push it to it's limit and also being on a lake that has 45mph speed limit. The boat prop is stamped with 14 19 R. By reading all the post here I assume I have a 14" diameter and 19" pitch. Yesterday I was able to get 5300 RPM without hitting WOT and I saw the RPM go higher a few times so probably means some slipping during accelaration. No problem at all going 45 with 4 adults and full tank of gas and I'm sure it will go much faster. I plan on doing some tubing and maybe some skiing this summer. I do not have any trim tabs but I tried the whale tail and didnt notice any difference as far as getting on plane faster on lower speed. So do I need to do anything with my prop size? Trim tabs would be nice too since I find myself looking over the windshield to get a better view until it planes out.

Clif

 

[steelespike]

Re: Opinions and advice

It will help you get us better info if you read the stickys at the top of the prop forum.
You should be able to find the gear ratio stamped or on tag on the outdrive.
My info indicate 1.43.Your prop is indeed a 14d X 19p.
Volvo nomenclature can be very confusing and there are a couple of guys here that
understand Volvo speak. Speaking generically trim down for hole shot.
You are over revving at 5300,
I believe the max is 5000.
45 mph indicates about 4000 rpm using 1.43 ratio and 10% slip.

 

[betroncm]

Re: Opinions and advice

Thank you Steelespike for the info. I did read the sticky but if it helps I will post my info according to the sticky which I copied below.

1) Performance issue you are trying to correct. Trying to find out if achieving over 5300 RPM(not WOT) means I need to change my prop size.
2) Current prop manufacturer, model, aluminum or stainless as a minimum. I do not know the manufacturer or model. Only know it's aluminum.
3) Current prop diameter and pitch (required). 14 diameter, 19 pitch and R for rotation
4) Wide open throttle RPM and speed with an average load (very helpful) As mentioned above..newbie so did not want to push boat yet but was able to hit 5300 and I'm sure that was not WOT. 4000RPM@40MPH cruising and this is with 4 adults, full tank of gas and some gear.
5) Engine/drive make, model, year, and HP. Chevy 350 V8(not original engine and dont know the HP) with Volvo Penta 275 outdrive(no stamp or tag anywhere but only name and the 275 on cover)
6) Boat make model, year, length and weight 86 Bayliner 19. Capri Bowrider weighing approximately 2000+lbs

 

[Maclin]

Re: Opinions and advice

Single prop Volvos are specifed the same as any other props, diameter and pitch. You are definitely over-revving so you need to prop up some. I would say minimum 21p and maybe a 23p. 4500 rpm with a 23 is about 54mph with 15% slip, assuming he 1.5 ratio is accurate.

 

[betroncm]

Re: Opinions and advice

Thank you very much Maclin. I will start with the 21 and see how that goes. I also ordered a set of trim tabs to help plane out faster.

 

[steelespike]

Re: Opinions and advice

If your doing smart tabs use the least amount of pressure to get the job done.
Too much pressure and the boat will run too flat wasting fuel and speed.

 

[betroncm]

Re: Opinions and advice

If your doing smart tabs use the least amount of pressure to get the job done.
Too much pressure and the boat will run too flat wasting fuel and speed.

Steelespike, yes I am. Thank you I will set it for low pressure first and adjust until I get the right setting.