Hey all,

I need to replace my propeller for my 1997 Mercury 115. It is on 18'10" Fazer Smokercraft, typically it is only my wife and myself. I am looking to get a better ride at full speed. I seem to have to have the motor in tilted further than I would like, cutting down on performance(top end speed). I really don't want a stainless prop, I fish a couple of areas where there are a ton of reefs/rocks, if I were to hit one it would probably cause more damage and be expensive to replace. Any suggestions would be appreciated. I am also looking for a source in S.E. Michigan or from the internet.

BOB

Bob,
Have you thought of a composite prop as an alternative. Check out this site:

http://www.piranha.com/propellers.php

These units have been rated as very reliable, and the site is pretty easy to navigate. You have choices in the 3 or 4 blade props. If you're running in an area with lots of obstructions, this alternative could save you a pile of money. They will work with you to get the proper pitch, and if you want, you can even get a second set of blades for those days that you're really loaded, or maybe to pull skiers, or those days when you just want a 'go-faster'. If you seem to be trimmed in all the time, a 4 blade prop would give you better performance trimmed out. They grab better in rough water, and would give you good hole-shot. What prop are you currently running? Good luck! Mike R.

I have a composite prop that I use for a back up I didn't like how it performed when I had to use it. I think the one I have now is a 13 3/4 X 15 , aluminum prop from Michigan Wheel. There isn't much writing on the prop to determine the pitch I measured the prop and it is approxmately 13 3/4 or 14 inches in diameter. That size and pitch was found on a couple of websites that sell replacement props.

BOB

Bob,
You might have to pull the prop and check the hub to find out size and pitch, although 13.75x15 sounds pretty close. What hp is the boat rated for? It sure sounds like alot of boat for a 115 hp. That said, moving up in pitch to gain better top end might be a mistake in overall performance. (loss of holeshot, slow planing, possibly lugging the engine) Where are you at as far as rpm's at WOT? I think it's important to know what you've got on there now. By the way, what brand of composite prop do you have as a backup? What size and pitch is it? Mike R.

The prop is off, the area where the size and pitch were is pretty worn, about all you can read is Mich___, I know it is a Michigan Wheel Prop. The composite prop is a Comp-prop 4x12.8x17 I only used it for a week a few years back when I bent my main propeller, it wasn't very efficient at high speeds. I really am not trying to get more speed I try to get my motor in a better(more effecient) position a high speeds. My boat is also rated for 175 HP. I also have a T-8 kicker on the left side, I think the additional weight of the kicker might be causing the problem, but maybe not with the boat rated for 175 HP. I run at approximately 4500 RPM at best. Thanks again for your help.

BOB

I believe that you should be running about 5250 WOT. At 4500, you may actually be running BELOW the minimum rpm range for that motor at WOT. You're probably going to have to drop pitch to improve performance. The 115 is only about 65% of rated hp. Usually 80% is the cutoff. On the plus side, if your rig is 'lugging', you might be able to drop pitch, increase performance, AND increase top end. If stainless is out of the question for you, I'd just get a good quality aluminum. Consider dropping pitch, and/or raising motor on transom. I'd take the prop with you when you go shopping, they might be able to clarify the current prop. Just my .02 worth. Mike R.

Bob,
In spite of your concern about potential damage if you have a bottom strike with a stainless prop, I think you will really help yourself if you go to a stainless prop.

If for nothing else, durability.
In the days when I ran an aluminum prop, I generally had 1-3 props fixed every season due to low speed bottom strikes. By this I mean, catching bottom when working unfamilar territory at idle speeds, launching or loading and happen to catch a bit of the bottom etc. Even a 2-5 mph bottom strike was enough to cause enough blade damage to require a blade repair.

However, in the years since switching over to a stainless prop - I have to say that I have never been back to a prop shop for repairs.
I still work the same waters, and still get the intermittent low speed bottom hookup. But the stainless blades are tough enough to shrug off these low speed impacts.

In talking to many different prop shops and marine dealers most of them tell me the same thing. i.e. If you are going at a low speed, and have a bottom strike with a stainless prop - you are likely to have 0 damage.

However, if you have a high speed strike with a stainless prop, and catch only the blade, it will likely be twisted or sheared off just as if the prop were aluminum. Yes, the stainless is tougher, but all of todays props are mounted in rubber, so if you had a terrific strike, it is more likely that you would shear the prop hub, before doing any gear case damage.

Conversely, if you take a high speed strike on the front of the lower unit - it won't matter if your prop is aluminum or stainless, you are still in for some lower unit work. However, that is what insurance is for. The insurance will cover your repair costs if that is the case.

Having said that - I woud chose a stainless high rake prop in the appropriate diameter and pitch to push your boat. Generally speaking there are too many variables to select a single best prop for a particular boat/motor combination. If possible work with a neighborhood dealer or prop shop and get a half dozen props in approximate sizes and try them all. Find the best prop or props that give you the performance you want for youar particular needs and driving style.

If you are like most of us who enjoy your boat, you will likely end up with several different props, that you might have use for at different times.

For example, in my case - I have a very low pitch stainless 3 blade prop that I use if I want to pull the kids on a tube or skies to give incredible hole shots at the expense of top speed.

Then, I have a 4 blade mid range pitch to give me the best performance when I am carrying three or 4 in the boat and know that I am going to be running a lot of rough water in the days outings. The 4 blade prop gives the best hookup and overall perfromance in mid range speeds with a heavy load.

Then, I use a 3 blade higher pitch prop for those times that there are light loads in the boat and want to increase the top speed.

Finally, I use a 3 blade - very high pitch prop for those times if I am running light, and want to do some long range cruising at reasonable rpm. Yes, it takes me a very long time to get on plane, but once I am on plane, I can throttle back, save gas and move along at a much better speed, than if I were running a lower pitch prop.

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So, lots of options for lots of different potential uses of a boat.

Take care
REW

REW,

No offense but I really don't want to put $300-400 in a propeller, let alone $1200-1600 for four different types of propellers that isn't where I want or care to spend my money. I want a mid-level prop to give me good performance for the situation that I described in one of my original post. It is usually just my wife and myself and our equipment. I also have a 40 gallon fuel tank, which when I am on vacation gets gradually lighter as the week progresses. I am alos thinking of a new boat and motor the next couple of years so putting a ton of money in this one isn't a priority either. I appreicate everyones suggestions and ideas.

BOB