posted 11-06-2000 08:02 PM ET (US)            

But I couldn't get it to work because my JAVA virtual machine complained:
"Applet PropSel can't start; error; java.lang.NoClassDefFoundError"

posted 11-06-2000 10:17 PM ET (US)            

I recently invested in a SS prop for my '74 Montauk with '94 90hp Merc. The boat came with 21" and 19" aluminum props. With the 21" I was getting about 40 mph on the Hummingbird at 5200 rpm at WOT. The engine is rated for 5000 rpm. The 19" had some damage so I had it repaired. The first time out I got about 37 mph at 5600 rpm at WOT. Until I dinged it up that same trip :-(

So I shopped around and ended up buying a Stiletto. Even though most people recommended I stick with a Mercury prop. But since they weren't buying...

I had two different recommendations, one for the 17 and one for the 19. I went with a 13.25x17 thinking that the increased rake, cup, and efficiency would make it run like the 19" aluminum. Sure enough the numbers are almost identical.

The SS is significantly heavier and the "clunk" is more noticable. I probably need to adjust my idle speed down a little.

Anyway, I found the best deal at Bart's http://www.bartswatersports.com . Got the prop for $219.88. Overtons was $274.99 for the same thing.

HTH,
Barry

posted 11-06-2000 11:36 PM ET (US)         

Twin Merc 60's 39 MPH
Twin Merc 75's 43 mph
Twin Merc 90's 49 mph
Twin Merc 115's 52 mph

posted 11-07-2000 08:47 AM ET (US)         

As to the SS v. Aluminum thread, I just tried out a SS prop from Midwest Propeller and learned something new. I have a 2000 Sport 13 w/ the 25 Merc 4-stroke. It originally came with an 11" pitch aluminum prop that let the engine run to 6,200-6,300 rpm trimmed up with a light load. I went with a 12" pitch aluminum prop, which dropped the max rpm to about 6,000. I then tried a 13" pitch SS prop from Midwest Propeller in the hopes of getting to 5,700-5,800 w.o.t. and was surprised when the engine dropped all the way to 5,400 at w.o.t.

I called Midwest and they thought that the dramatic drop was due to the fact that the SS prop had greater cupping. Stainless can be bent further than aluminum without breaking, so a SS prop typically has more cup than the comparably sized aluminum prop. The extra cup "grabs" the water better, which lowers the rpm at which the motor can run.

posted 11-07-2000 12:19 PM ET (US)            

Then I had to get MS-Explorer 5.0, because my old faithful Netscape uses its own JAVA and can't use the external version.

So, after installing all that, I finally got to see the Mercury Propeller Calculator! But...

I still seem to have some trouble with screen redraws, where the black background covers the JAVA window. Probably due to the smaller monitor size I am using.

Argg! Stuff like this is one reason I try to keep this website running as simply as possible. It works for most any kind of browser, OS, monitor size, etc.

That MercuryMarine.com website looks like they have poured plenty of effort into it. Maybe some day I'll be able to see more of the results!

posted 11-07-2000 01:50 PM ET (US)         

I didn't see much room for variety in diameter in OEM/OEM replacement props. (I don't want to get into highly raked Ballistic/Stiletto props). There only seems to be slight variation in the available diameters, with higher pitched props having marginally smaller diameters. If you look at the available diameters for my motor, they only range from a max of 10 and 7/8" (11" pitch) down to about 10 and 3/8" (13" & 14" pitch).

Are you aware of other diameters, given the limitations inherent in the low h.p/small gearcase? Thanks for your interest.

posted 11-16-2000 01:33 PM ET (US)         

Two years ago Mercury came out with an improvement, with four different size plugs being available to fill the larger, round, cast hole in the props. This allows the user to select the amount of "over blade" exhaust ventilation desired by the user, for maximizing the boat/prop combination. The options are full plug, or small, medium & large vent holes. All Mercury SS props now are cast with these holes, except for the "elephant ear" Vengeance Series.

As Clark indicated, the ventilation allows the engine to rev up higher on take off, allowing quicker acceleration. Generally, the larger the hole, the faster the boat will accelerate, but the greater the boat speed will be needed to keep the prop from slipping. At all vent hole sizes, once the boat is doing over 30mph, the exhaust is bypassing the vent and is no longer flowing over the blade. On most boats, a vented prop, such as a "Laser" or "Mirage" will walk away from a traditional prop in the acceleration category. Do not confuse these with the non-hubbed racing props, often used by the Cigarette style boats, which will literally sit and spin, with great amounts of exhaust noise, until they slowing get underway. Those are only top speed props.

I run counter rotating ventilated Laser II
props on my 25 Outrage, and when accelerating, the engines pop right up to 3000 rpm (where they can quickly generate more HP) and the boat planes off. You can feel the tremendous acceleration as the props continue to dig in, necessitating a quick backing off of the throttles. People trying out the helm on my boat, unfamiliar with this type of operation, often find the boat speed running away from them before realizing to back off the gas.

posted 11-17-2000 10:12 AM ET (US)         

Ditto, on the throttle, it is the same for most boats.

One of the mistakes new boaters make is to not shift into gear fast enough. they are trying to be to gentle. You want to put it into gear so that the shifting dogs aren't chattering, then give the throttles a good nudge. Lugging the engines at dispalcement speeds is bad for the motors (especially 2 strokes), wastes gas, blocks your view, and makes large wakes. So get the boat up
on plane thane back off, like you stated. Marine engines are designed for this.

posted 12-12-2000 07:06 AM ET (US)         

Sort of the way of life on the net and has been for a few years now ---

However, this little program makes us folks who are paranoid about privacy a little more secure --- www.webroot.com try it you'll like it!

posted 12-13-2000 01:04 PM ET (US)            

As for as the utility that Bigz mentions, if you have not downloaded it and installed it, you probably do not have it.

I am going to have to try that utility myself. I have never had a problem with “malicious” cookies, but am always interested in good utilities to make the web safer for all.

Hope this helps,

posted 03-16-2001 09:24 AM ET (US)            

Thanks for the input

posted 04-25-2001 02:47 PM ET (US)         

Blackdog - I assume your Dauntless will run about 40MPH with 115HP. You are just about at the break point where a performance SS vs a regular SS should be used. If you're looking for a little more bow lift, go with the performance lines such as a Rapture or Stiletto. Although Mercury now makes the interchangeable hub for their props (allowing them to be used on any brand engine), for mid sized 4 1/4" gearcases like yours, they don't offer the performance props until 20" pitch.
Here, once again, the experts are telling us something. In the Mercury line, you would use a non-vented Vengeance prop for your engine, either 16 or 18" pitch. Your gear ratios could make a difference here also.
Look into one of these for your OMC. The Vengeance is an excellent prop, and does give a little more bow lift than an aluminium.

posted 04-25-2001 11:11 PM ET (US)         

"The Flo-Torq II (name for their interchangeable hub design) is also designed to resist slippage, yet still flex during engine shifting to cushion and protect the drivetrain from impact".

I do not know if the Stiletto brand has a cushioned hub to protect the drivetrain. Not familiar with the Solis Titan at all. I have heard of the Turning Point props, especially their new "performance aluminium" for about $90/each, but that is another subject. I was about to buy a set of Stiletto props for my 18' Whaler, mainly because of price, but from what I have recently learned about the ease of re-selling high quality Mercury props, (internet now makes this much easier) I am thinking it's smarter in the long run to buy the top of the line, which they are. Nobody, including other engine mfg's, knows props, or makes better ones, than Mercury in my opinion, especially when you get into SS and the higher performance models. There is a lot of info on their props at mercurymarine.com, including a pitch calculator (your browser has to be set to accept cookies to get on). They have a huge selection of styles, and their new adjustable venting system seems like a great feature, exclusively by Mercury. If you've ever had a boat with a Merc on it walk away from you, the Merc prop is probably one of the main reasons!

I should also mention that Mercury is selling some of their older style props, through the catalog houses, as "Quicksilver" props. these are similar in design, but not as highly polished, and with fixed, rather than adjustable, venting. Price only seems to be about $20/prop less than the Mercury line bought right, so I'm thinking it's no great deal. Aluminium, Vengeance, Laser and Mirage lines only, are available under Quicksilver branding, but they use numbers instead of names to identify them.

posted 05-04-2001 07:15 PM ET (US)         

There are three possibilities, the safest being the 18" pitch Vengeance prop. These are good performers and will definitely improve overall performance, including hole shot, bow lift and speed. This is the highest pitch offered in the 4 1/4" gear case size. Prop part # is 48-16988A45, with hub kit #835266A1 (for an OMC engine).

Depending on the engine's gear ratio, which I don't know, it's also possible the engine will turn the more sophisticated, PVS vented, group of props, either the Laser II or High Five. These begin at 20" pitch, and it's possible your engine may turn one of these. The Laser is faster than the 5 blade, but if you need acceleration and exceptional smooth running, the 5 blade could really help. The venting (for acceleration) is adjustable, all the way from closed to a fairly large hole. Engine should probably be up 1 1/2" to achieve surface piercing and get the most out of one of these. Running them fully submerged effectively increases pitch by 2", and that would be too much for you.

A third solution would be to use a Stiletto 3 blade performance prop, since they make them in 19" pitch, which could also be just about right.

Clark, if you're following this, could you add anything here from your experiences, including the 5 blade?

posted 05-10-2001 10:23 PM ET (US)         

Generally Mercury recommends that if switching from their odd numbered pitch aluminum props, you go up 1" in the performance enhancing series. So that would mean 22's. But you also have to raise the engine at least 1 bolt hole for this situation, so that the prop begins to operate surface piercing. If you do not raise the engine at least one or 2 bolt holes, and run the prop fully submerged, you should go down 1", and use the 20" pitch, since these things take a big "bite". Your top speed will still be the same, but you will gain the other benefits. You will have to experiment with the various (or none) venting sizes. I think the medium size plastic vent plugs come standard.

posted 05-15-2001 12:38 PM ET (US)         

The Mercury tech recommendation sounds good also, as these newly designed 4 bladed Trophy Plus plops are supposed to be much better than the original Trophys. Dropping down to 19" pitch with one of these would be right also, as unless they are highly elevated, 3" or so, they take a big bite on the water, necessitating lower pitch. But they still have to be run at least 2 bolts up from the lowest position.

posted 05-15-2001 07:29 PM ET (US)         

For all of the large gearcase V-6 engines, most of the manufacturers use odd numbered pitches. As you know, I use 23's on the 25.

But the 115's are the mid size case (4 1/4" dia tube) and Merc sizes most of those performance props in the even numbers. I use 22" pitch Lasers on the 18.

posted 05-15-2001 07:58 PM ET (US)            

Now, if the light prop breaks a blade early
and the heavy prop doesn't, the tables are
turned.

posted 05-16-2001 03:17 AM ET (US)         

I am convinced that an SS prop is MUCH more likely to get you home if you DO hit something. They are 5 times tougher and will stand up to 5 times more abuse, and can often be bent back on the spot enough to continue on, until a proper repair can be made. We buy insurance for serius damage to an engine propshaft if it should happen anyway. Don't see any reason for running around with less than maximum performance so you can save an insurance co a few bucks.

posted 05-16-2001 03:20 AM ET (US)            

If a hard object were to be struck, such as a large rock or log, the most protective of the lower unit would be the comp prop first, aluminum second and after that stainless which would depend on the shear factor of the hub insert more than aluminum.

If a soft object were to be struck, such as a mud with pebbles, sand, small plants, the advantage would be in stainless where there would be no damage. While the aluminum would burr, blunt and or chip, gouge, unblancing the blades requiring replacement and the damaged prop to be refurbished (at around $50 min.). A few times at this and stainless becomes very cost effective.