[Maddog]

Ok first post and first boat go easy on me. I have a 1994 Mariah 212 z shabah, Alpha One Drive with 350 Magnum with work done to the motor. I now have a Aluminum 14.?X23 pitch prop. Previous owner states boat will do 60+ mph. Have not WOT (to nervous ok scared) have not been in smooth water yet. I don’t know my gear drive ratio. Boat weighs 2600, I will be pulling Big 2 man tube, skiers heavy 160 to 250 lbs and wakeboards I want to have 4 to 5 people in the boat so I’m adding another 1600 lbs for all passengers and gear. Total of 4200 lbs
The 23 pitch just won’t get on plane very quickly somewhere around 7 to 10 sec (maybe longer) with 3 in boat 2 on tube. Moved two people to front (helped). I expected the boat to “jump out of the water” It doesn’t.

Not worried about top speed yet, @ 35mph it felt like 100mph lol maybe somewhere around 50-55
I want the boat perform then I might try Smart Tabs.
Low elevation San Diego to 4000’
Trim all-down
Would like to save on gas if possible

With the boats paper work I have a dyno sheet (will attach if I figure it out how to)
The dyno sheet:
Max Hp is achieved @ 5859RPM - 369.5 Ft-lbs torq – 412.2 CHP
Max Tourque is achieved @ 4900RPM – 412.4 Ft-lbs torq – 384.8 CHP

Questions:
What is my recommended rpm range
Gear Ratio
Propeller Slip
Suggested prop size

PS what is "Post a Poll" and "Separate tags" on posting?

Ok, Thanks in advance for this long winded question.

[mikeyt]

350 Mag with the Alpha 1 is 4600-5000 rpms at WOT. I'm not gonna get into all the extra work you've done to the motor but.....we kinda really need to know what speed is your top speed & what rpm's you are at when you're going at top speed. Wait for some smooth water...

I suspect what you may need to do is drop to a 4blade (or even a 5 blade prop) for some extra bite. I also suspect you might just have a little room in your WOT rpms with the 23" pitch to do this w/out going well over the 5000 mark but lets wait & see what your numbers are.

Another option would be to install power tabs such as Bennett's or Lenco's etc. Given the size/weight of your boat you may just be beyond the use of Smart tabs.

[al levy]

that prop will probably work for top end with not a lot people and definitely no skiers. unless you have a lot of work done to motor look for the maximum rpms on the motor label. if you want to get out of the hole with a lot of people you might try a 22pitch 4 blade but if your really loaded a 20 pitch 4 blade will really work just dont over rev.

[Maddog]

Damaged prop at Lake Mohave had to go to the marina at Katherines Landing to purchase a new prop. They guys at the marina were trying to talk me in to a 23 pitch 3 blade(Been there done that..)
(also, I was educated from Mariah Owners Club site). I decided to go with a 19 pitch 3blade WoW !!! Never had great acceleration with the 23 cruising at 40 mph I now hit the throttle with 5 people in the boat and tada acceleration I’m amazedat the 19 pitch. With the 23 pitch we left the marina with 5 people ice chest chairs food tools etc.. we were “Loaded” Tried to plane What seemed like 5 min was more like 1 ½ maybe longer it wasn’t good, no acceleration what so ever. Broke the 23 pitch ,purchased the 19 pitch for $130 and was happy to do so. Re-launched the boat went to plane, it took seconds to plane it was the first time I felt the bow being pushed down. Tube and cruised around for the next three days and Im loving the new prop. Thanks to all who took there time to respond to Mariah Owners Club.

[93Shabamag]

Hey Maddog.
Running 21 pitch Merc, Lazer 3-blade in 93 Shaba 212 W/ 350 Mag. Naked boat, good water, min. fuel and just driver 62 MPH. Reality boating people,fuel, coolers, skis, tube, chairs,2 batteries,etc. 55 MPH . I know I don't have enough motor for a 23 pitch. Boat cruises at 3600 at 42 MPH great river speed. Check it out and good luck.

[darkcalling]

Yeah sounded like you were way over propped. Not that I should talk I am running 26 pitch dual with a 502 stock so far planing is so so imo. But with 5 people and 2 100lb. plus dogs and 3/4 of a tank of fuel and gear and stuff we hit 64mph. Thats when the little woman gave me the arm slap to back off so I know theres more still lol. But for pulling and playing I found on my old 20' 19 to 20 pitch props 3 or 4 blade worked best.

[Mariah350]

Originally Posted by Maddog

Ok first post and first boat go easy on me. I have a 1994 Mariah 212 z shabah, Alpha One Drive with 350 Magnum with work done to the motor. I now have a Aluminum 14.?X23 pitch prop. Previous owner states boat will do 60+ mph. Have not WOT (to nervous ok scared) have not been in smooth water yet. I don’t know my gear drive ratio. Boat weighs 2600, I will be pulling Big 2 man tube, skiers heavy 160 to 250 lbs and wakeboards I want to have 4 to 5 people in the boat so I’m adding another 1600 lbs for all passengers and gear. Total of 4200 lbs
The 23 pitch just won’t get on plane very quickly somewhere around 7 to 10 sec (maybe longer) with 3 in boat 2 on tube. Moved two people to front (helped). I expected the boat to “jump out of the water” It doesn’t.

Not worried about top speed yet, @ 35mph it felt like 100mph lol maybe somewhere around 50-55
I want the boat perform then I might try Smart Tabs.
Low elevation San Diego to 4000’
Trim all-down
Would like to save on gas if possible

With the boats paper work I have a dyno sheet (will attach if I figure it out how to)

The dyno sheet:
Max Hp is achieved @ 5859RPM - 369.5 Ft-lbs torq – 412.2 CHP
Max Tourque is achieved @ 4900RPM – 412.4 Ft-lbs torq – 384.8 CHP

Questions:
What is my recommended rpm range
Gear Ratio
Propeller Slip
Suggested prop size

PS what is "Post a Poll" and "Separate tags" on posting?

Ok, Thanks in advance for this long winded question.

I think you are running the 250hp carb version and not the 300hp MPI version?

In my own testing when I was running the stock 350 Merc 250hp the Mercury Laser II 21' was the best top speed prop.
Stay away from Mirage props if you have a alpha one drive which will pull your rpm down to much. With the 21' Laser you will run around 53mph gps on good water (slight chop).

Note: I currently run the same 21' Laser II with my 355 Perf Motor but at a higher RPM past the stock rev limiter which is 5200rpm. The laser is a great prop for the 212 Shabah due to it's narrow beam and light bow. Stingray boats have similar narrow beams and if you visit there web site you will see that they to recommend the Laser II.

[Maddog]

When looking at the dyno sheet what is telling how much horse power I have? Dyno states “Max Hp is achieved @ 5859RPM - 369.5 Ft-lbs torq – 412.2 CHP “ is that 400hp and whats “chp” after the 412.2?. Yes, it’s a carburetor I believe Its been replaced

[Maddog]

Due to my inexperience in boating I want to stay with an aluminum prop. As I demonstrated at Lake Mohave when I broke the prop. I was told when you do hit something with aluminum prop its easer on the out drive the prop will give.. I would of liked to go with a 4 blade prop but it wasn’t an option at the time.

I may have gone to low with a 19 pitch but it is a 3 Blade. With what I’m doing so far the 19 3Blade seems to working great.

[darkcalling]

I can tell you from over 20 years of experience with small block gm which is what the merc is that revving that thing at near 6k for any amount of time in stock form it won't last a weekend without spinning a bearing or worse. Not sure where that sheet came from but a stock gm small block red lines at 5k in a crate over that your on your own. As for the alum being easier on the leg I can tell you that is a fact I had a mirage ss on my other boat hit soemthing and the prop was basically fine the shaft in the leg broke.