18' with Merc 115 (1988 Both of them) Best Prop?

[gman1001]

Looking to re-prop as the current one is mangled. Thinking a 13/19. I will occasionally teach the kiddoes water skiing but they are small and light. Top speed is not an issue for me but its nice sometimes to go really fast. Moreover looking for good all around performance.

Aluminum is the only way to go for me as there are too many rocks in Long Island Sound CT.

Tx!

[Fr. Frank]

What is your current max rpm with your current prop (before it was mangled) What model is your current prop, Mercury/Quicksilver Black Max?

I need more data, then I can help.

[gman1001]

Hi there, I just bought the boat so I can't speak to the RPM's. I'll take the old prop off this wknd to see the brand etc...

[mnwnvc]

I have an Opti. and am running a Michigan Apollo 13.125 X 19 Stainless from Len's Prop Shop- I think. I like this prop very much WOT 41 mph Good hole shot. 2 Aluminum= 1 Stainless. Stop hitting rocks you will love the improved performance.

M

[gman1001]

Tx for the info... Thats the direction I'm leaning....

Took the boat out today for maiden voyage. (with mangled prop) Boat rides so nice, can't wait for a new prop. Can't report back on RPM as my RPM gauge is stuck at 1k with motor off. GRRRR.

[gman1001]

Whats everyone think of Michigan Wheel Corporation Props? Cabelas is running a great sale on these... Worth it?

[Bushwacker]

I've had 3 Michigan props; they make good stuff. The plastic hub of the new 2-piece hub system is significantly more robust than the plastic piece of the Merc system. The aluminum versions typically have more ductile alloy than the factory props, which means they'll bend rather than break if you hit something, so they're easier to repair. I had an MWC aluminum 13 3/4 x 15P 3B for a spare when I had a 115 on my boat and it was perfect for heavy loads. Your boat is probably lighter than my Seafari, so you could probably run a 14 1/4 x 17P on your boat. I'd stay with the aluminum version till your sure how much load you'll typically have, as a good prop shop can rework it + - 2" in pitch to get it dialed in so you're turning max rpm with the heaviest load you plan to run. If you're stern heavy and can't plane down to about 12 mph, consider a 4 blade prop and maybe even a Doelfin, both of which will give you more stern lift. If you run in rough water a lot, it's nice to be able to plane at low speed!

I now have 2 MWC props, a 4B 14 x 20 Vortex (aluminum) and a SS 4B 14.125 x 20 Apollo as spares/light load props. Had the Vortex repitched to 18", so it's a good heavy load prop. The Apollo is the most efficient light load prop I've run; I also tried a 3B SS 15 1/4 x 17P Mirage 3+ that everyone raves about, but the Apollo turned the same rpm, was about 3 mph faster, would plane about 5 mph slower and was about .5 mpg better in fuel consumption! Have tried 4B SS 15x17P and 15x15P PowerTech props; currently running the 15x15 for heavy loads, but the Apollo gives me the best mpg of all of them, measured with the I-Command system which uses a gps spedo and fuel flow from engine computer.

[McGillicuddy]

I have no problem with them. I took one an alum Vortex I think off my I-6 merc 115 because it was way too much pitch for my Seafari. I went to a 17 p black max and it was still too much pitch. A 13.75x15 black max is perfect for my rig. I get 36mph @ 5500 rpm and 2.1 mpg while cruise gets 2.4mpg at 4000 rpm for 24mph.

I would, however, suggest you try a Merc Black Max or Quicksilver Black Diamond in a 13.25 dia. x 17p. you might even get away with a 19p. My prop guy loaned me 3 props (2 of them stainless) and said bring me back some good notes - didn't even ask for a credit card. I would see if you can borrow a black max/diamond (everybody has a few of these in their shop).

BTW I got 2 new black maxes on ebay for $50 each so look around. Both had flo-torq II hubs included, also...

[gofastsandman]

; I also tried a 3B SS 15 1/4 x 17P Mirage 3+ that everyone raves about, but the Apollo turned the same rpm, was about 3 mph faster, would plane about 5 mph slower and was about .5 mpg better in fuel consumption!

That left a mark. Chagrin, chagrin chagrin. How did he do that. Top end too? More stern lift= less wetted surface = more mph.
GFS
Going out this weekend D. ?
Any good stories from O.F.F. ?

[Bushwacker]

[/QUOTE]. . . How did he do that. Top end too? More stern lift= less wetted surface = more mph.
GFS
Going out this weekend D. ?
Any good stories from O.F.F. ?

[/QUOTE]

Hey Sandy,

I can't really explain it other than maybe it's just a more modern, more efficient prop; maybe less slip with 4 blades. More stern lift SHOULD produce MORE wetted surface and more drag. However I could trim the motor higher with the Apollo before it started to porpoise than with either the Mirage or PowerTech props, so that might explain the higher speed.

Will not get out this weekend; but did fire up the motor a few days ago. Wife had emergency surgery on her stomach 3 wks ago, so still playing nursemaid! May get out sometime next week.

There was some great movie footage of old races; I had asked Skip if he was gonna bring the 21, but he said no, it's not ready yet. Well, there was an old Bertram Moppie there in early restoration (teardown!) phase with the drives and engines removed, but nothing more had been done on it, so I think he may reconsider for next year!
Denny