Keep Same Prop or change???

[Fischer18SeaRay]

I am currently running a 13 dia. and 17 pitch on a 18 ft. Sea Ray with 115 Inline 6 merc...One of the blades the tip is all chewed up and needs replacement..My question is that should I just get another prop with the same specifications or does anyone know what kind of impact changing the dia or the pitch would have on the performance of the boat...Could I get better performance if I stayed with the 13 in. dia. but went to a 19 pitch?? And what prop company do you guys prefer

 

[walleyehed]

Re: Keep Same Prop or change???

The first question at hand would be what is your wide open throttle with the prop you have now,or as it was in good shape, and what is the primary use of your boat?

 

[Fischer18SeaRay]

Re: Keep Same Prop or change???

WOT is about 5700-5900.....The Primary use of the boat is fishing and tubing/waterskiing...I had just fix the transducer this morning so I dont know the exact mph...Usually though wop is 40-45mph

 

[walleyehed]

Re: Keep Same Prop or change???

OK, your RPM looks real good...that engine runs great at 5800-up.<br />Diameter is not a big issue unless with the increase, it includes a much larger blade area, which I don't think we want in this case.<br />13 to 13-1/2X17 should be good and keep the blade area near the same.<br />Check the iboats prop finder and you will see many props available right here. There are some good deals on some better design aluminum props that you might want to look at as well...check the prop finder....

 

[Fischer18SeaRay]

Re: Keep Same Prop or change???

Thanks for your time...Do you know what kind of change I would get if I changed the pitch to a 19 instead of a 17????

 

[walleyehed]

Re: Keep Same Prop or change???

You'll lose "roughly" 350-400RPM, and your hole-shot would not be as good, and most importantly, it will drop your RPM down lower than where it should be for best life, efficiency, economy, etc...

 

[Fischer18SeaRay]

Re: Keep Same Prop or change???

This past weekend I replaced the damaged Propco prop 13.25 dia 17 pitch with a Michagan exact replacement..... same specifications 13.25 dia 17 pitch..The boat has lost its hole shot and the boat creates alot more wake now then it ever did..The michigan also seems to have given the the back of the boat a rooster look...The prop propels the water up and it looks like the head of a rooster....Any ideas why would this prop make the boat create more wake and that rooster tail if I replaced it with the same dia. and pitch prop?? Do I need to trim the motor??

 

[walleyehed]

Re: Keep Same Prop or change???

The Michigan and the propco are 2 totally different manufacturers, and obviously, one has more lift in other areas than the first.<br />"Michigan Match" means an exact OEM replacement...a Merc prop...the propco is a whole 'nother ball of string.<br />Do you have power trim or just manual with the tilt pin?<br />The Michigan shouldn't be a problem..in-fact it's got thinner blades than the propco-should be better.<br />Do we have an RPM figure to compare between the 2 props??? speed???

 

[Fischer18SeaRay]

Re: Keep Same Prop or change???

It has the manual tilt pin...Propco Wot was 5600 at 40 mph....Michigan is 5800 rpm at 32 mph...