Aluminum to Stainless - Size - Mercury 175

[jkering66]

Hello,<br /><br />I have a 175hp Mercury outboard on a 21 foot Grady Wihte, Overnighter. The existing aluminum prop I have works good on the boat, but I would like to move to a stainless.<br /><br />The existing prop is: 48 78115 15P<br /><br />PROP NO. 48-78116-15<br /> RPT NO. 15R11<br /> PITCH 15<br /> RAKE 11 DEG<br /><br />What would be a comprable stainless prop that could replace the exixting aluminum. <br /><br />Thanks, I could not find to much information on the web.<br /><br />-Jack-

 

[Tail_Gunner]

Re: Aluminum to Stainless - Size - Mercury 175

The guru's in this forum will need a bit more concise info than what you have provided to suggest any type of size of prop.<br /><br />Wide<br />Open <br />Throttle<br /><br />That Wot is a bench mark that is use to determine your current engine, hull, and prop preformance. So if you can post your speed @ wot and your rpm @ wot you will get first a response and secondly very sound advice...... .......Oh what type of preformance or gain you are looking for aka top speed hole shot (sking or multipassenger cruising preformance) type of boat or hull. They take this serious and do a great job..

 

[jkering66]

Re: Aluminum to Stainless - Size - Mercury 175

Thanks Tail_Gunner,<br /><br />WOT Speed: 38 <br />WOT RPM: 5300/5400<br /><br />Looking to increase top end speed without increasing RPM.<br /><br />Thanks.

 

[Dhadley]

Re: Aluminum to Stainless - Size - Mercury 175

Looking to increase top end speed without increasing RPM.<br />

Aren't we all?? Well, at least I am.<br /><br />Anyway, are you sure that's all the rpm you want to spin the motor? What year is it?

 

[WillyBWright]

Re: Aluminum to Stainless - Size - Mercury 175

Merc V-6s like 6000 RPMs, but you didn't hear that from me. <br /><br />I'd stay with the same pitch. The thinner stainless blades should get your R's up, and R's mean Hp means speed. You might consider raising the motor on the transom unless you boat in rough waters and need the deep bite. Merc makes a wide variety of stainless props. If your boat is a$$-heavy, you might consider a Mirage for stern lift. A Laser will give you good bow lift. There are QSS economy stainless props that perform just fine. 3-blade props like to run fully submerged. 4- and 5-blade props can pierce the surface and that allows a higher motor height which means less drag which equals speed. Ventilated props help with holeshot. I'm not sure if all this helps make the decision easier or more difficult. <br /><br />For the closest stainless to your current aluminum I'd suggest the QSS.

 

[jkering66]

Re: Aluminum to Stainless - Size - Mercury 175

Thanks for the replys.<br /><br />The Mercury 175 is a 1988 and runs great, the RPM is probably closer to 5500 currrently, not looking to increase RPM. I have never owned a Mercury, but for the past 3 years, this thing has been great.<br /><br />If I put this prop on my boat, what type of functionality would I get, less rpm, less speed, better hole shot? If a mirage will increase stern lift, that would be a plus for me.<br /><br />Mirage<br />48-13700 A 45 19P<br /><br /><br />Thanks again.