Triple Monty Power on a Scarab.

[kimswang]

I just dropped off my three motors at Monty Racing and the project is on its way. I also have my three gearboxes at Bob's Machine Shop for low water pickup cones to be mounted as well as a repair of a cracked driveshaft. I will do the midsections myself at home plus whatever else is needed for the boat. I will post pictures from the home computer as I go along. One of the questions right now is prop choice. Monty highly recommended Bravo Ones so I am naturally leaning in that direction. The next question is the size, I did a little math and came up with a 27" pitch for a speed of 88MPH turning 6500 RPM. Does this sound about right? Who sells these props for a descent price?

Wish me luck on the project, it's been long going and I'm very excited to see it all come together with the performance I'm hoping for.

Kim !

[Mr. Demeanor]

PropGods.com has a propeller testing service that might be your best bet. I know the owner and have used the service. Super good guy to work with.

[STV_Keith]

I'd suggest you start with some 24's, to get a baseline. With the 1.76:1 ratio in the OMC cases, this would put the boat at about 72mph at 6500...roughly what mine runs.

Call Kevin at R&R. He may have some used props you can start with and try. As long as you don't damage them, and need to move up, he'll give you full credit on different wheels. 702-564-7502. He can also CNC machine PVS holes into Bravo props, which you may need to ventilate them and get them out of the hole.

[baja200merk]

I'd suggest you start with some 24's, to get a baseline. With the 1.76:1 ratio in the OMC cases, this would put the boat at about 72mph at 6500...roughly what mine runs.

Call Kevin at R&R. He may have some used props you can start with and try. As long as you don't damage them, and need to move up, he'll give you full credit on different wheels. 702-564-7502. He can also CNC machine PVS holes into Bravo props, which you may need to ventilate them and get them out of the hole.

why start there if hes got 400 more hp than you? Is yours a 34 also?

[STV_Keith]

Nope, mine is a 30 and doesn't have all the goodies (weight) that he does. I wanna say he can carry 100 gals more fuel, has a kitchen sink in there, among other things.

[rchevelle71]

Sounds like a fun boat, but that fuel bill is gonna be insane.

[STV_Keith]

Mine cruises at 43-44mph, turning 4100rpm. Burns 19gals/hr per motor at that rate.

[kimswang]

Keith, Monty said no sweat making 80, the goal is still 88 and he thinks that might require proper tuning....... The hull weight of mine is 5100lbs. For the 88 to be achieved all extra weight will come off.

Rchevelle, maybe, but different from three new motors, I dont have the insane monthly payments for years......

And I will definitely call Kevin Keith.

[fastcat1]

Kim wish you lots of luck. I know it’s going to come out great. You have been thinking about this for a few years now.
Are you modifying the mids in any way? Are you keeping the exhaust below the water or opening them up? Three V8s with open exhaust must be a great thing to listen to. What kind of hp is Monty going to work the motors? Are you cowling stock? Man those things are heavy.

[kimswang]

Kim wish you lots of luck. I know it’s going to come out great. You have been thinking about this for a few years now.
Are you modifying the mids in any way? Are you keeping the exhaust below the water or opening them up? Three V8s with open exhaust must be a great thing to listen to. What kind of hp is Monty going to work the motors? Are you cowling stock? Man those things are heavy.

Thanks. The mids are staying stock just like the cowlings. They might be big but they're not that heavy. Monty is building the motors to be very similar to STVKeith's motors, just a todd more power. So hopefully we will see each one right north of 400HP. It should move my fishing dinghy pretty good, and for a long time. The lower units are all done by Bob's Machine shop and I'm in the market for some 29" Bravo One's. I need two LH and a RH. Right now I have a set of 22" Rakers and a set of 26" Rakers. It feels astronomical to finally getting all of it together.

[STV_Keith]

While odd-number pitch Bravos are technically available from Mercury, I've never seen one in the flesh. You'll have much better luck finding a 28p. If you really need 29p, Kevin can tweak them up for you.

[MercNuts]

Mine cruises at 43-44mph, turning 4100rpm. Burns 19gals/hr per motor at that rate.

About 40 gals per hour (assuming that is twins and not triples) to go 43 to 44 miles or 160 to 200 bucks depending on land or water fuel cost to go that 43 to 44 miles.
That's 4 to 5 bucks a mile in fuel cost alone at cruising speed if my math is right. I hate to think what a WOT blast of several miles would cost.

[baja200merk]

About 40 gals per hour (assuming that is twins and not triples) to go 43 to 44 miles or 160 to 200 bucks depending on land or water fuel cost to go that 43 to 44 miles.
That's 4 to 5 bucks a mile in fuel cost alone at cruising speed if my math is right. I hate to think what a WOT blast of several miles would cost.

If you can afford to buy 3, 400+hp powerheads............. well you get it

1mpg is not bad for a 30ft boat with 800hp, my 21ft only gets 2ish with a single 225!

[Mr. Demeanor]

If you can afford to buy 3, 400+hp powerheads............. well you get it

1mpg is not bad for a 30ft boat with 800hp, my 21ft only gets 2ish with a single 225!

Would love to someone do it with a faster hull. That magical 88mph maye have something to do with 87.XX being the official center console speed record set by a Fountain 38 with quad 300XS. Unofficially (by gps) Propbenders 38 Fountain on thehulltruth.com has already gone 88mph with quad Merc 350SCI.

88mph with a full blown CC (with a top?) is going to be very tough with "only" 1200hp. The 38 Fountain is probably the fastest platform and needs 1400hp to get there. Very cool project and keep us posted on your numbers.

My 26' Fountain gets 3mpg at 35mph with a single 225. Propbenders 38 gets around 2mpg at 50mph if I remember correctly. Pretty amazing.


Edit: He sold his quad 38 and is having a trip 300 Verado 39' Nortech CC built.

[baja200merk]

My 26' Fountain gets 3mpg at 35mph with a single 225. Propbenders 38 gets around 2mpg at 50mph if I remember correctly. Pretty amazing.


Edit: He sold his quad 38 and is having a trip 300 Verado 39' Nortech CC built.

I should have said "CARBURETOR MOTORS". Your fountain has an optimax on it, thats a different world....

My paramount got around 3.5mpg with a direct injected 975hr 200HO E-tec over a few trips with different stages of abuse/load. 2-6 people + coolers, 3500rpm 30mph cruise with a 23, 4500 45mph cruise with a 26. With a carb motor and the identical routine got around 2mpg on a good day. My 150hp 60* was much worse on fuel than a 250 DI and I was easy on the 150 (it was a 20in and would cavitate to the limiter on a long WFO pull. the 250 was beaten like a circus animal ). Expecting 3 400hp carb motors to get anywhere near a direct injected engine sorry,

edit:I had to fight my uncles 2010 22 whaler revenge with a 250 verado to get 2.4mpg at 25mph conditions had to be PERFECT, tabs, load, trim all made it hover around 2.