Seamaster 27 Performance - Page 2

gofastsandman · #11 09-18-2011, 07:48 PM

Brian,

The Mirage+ has good cup by the hub for stern lift and a nice progresssssive tip. I think I have the Merc hub kit.
3 Blade, but interesting.

Cheers,
Us

lost2a6 · #12 09-18-2011, 08:22 PM

Seems like that boat would have a Bravo II drive, that's what took place of the old TR drive. It was made for big heavy boats and could swing a 20" diameter prop if I'm not mistaken.

McGillicuddy · #13 09-19-2011, 12:54 AM

Hey Brian, when you gonna post some pics of the Amazonian mistress - perhaps you have and I missed the post...

I agree with Steve about the drive but you have the Bravo I and so it goes...

I'd be curious to learn specifically what prop you're running and your performance numbers. How quickly does she get on plane and low low will she hold a plane.

If your PT prop is the MQS series, I think you might just need more pitch. If its not, that model might be the ticket, or maybe the four blade version (MQS4). Get your rpm numbers to WOT with a load and go from there. Try to borrow a Black Max/Diamond (allegedly the same shape as the MQS)in a 17 and 19 pitch and see where you are (they are easy to turn so you might even get up to 15x21). Any shop should have a dozen of those on the wall and be willing to let you give it a go.

Obviously its not the same boat but that geometry totally changed my overall Seafari's performance.

I have often heard it said that the Mirage + is designed to be wound up so I don't think is going to be effective at your target rpms or projected speeds but if Sandy's willing, heck give it a try.

Good Luck

gofastsandman · #14 09-19-2011, 09:06 AM

I turned fewer rpms with the Mirage than the Apollo 4 bl but the apollo was a 19 or 20 p so the mirage 17 will bite.

Come on folks, let`s find Brian a sweet prop for that Seamaster.

Cheers,
GFS

gofastsandman · #15 09-20-2011, 09:07 PM

Quote:

Seems like that boat would have a Bravo II drive, that's what took place of the old TR drive. It was made for big heavy boats and could swing a 20" diameter prop if I'm not mistaken.

The Lost one knows his I/O`s. You guys should talk shop.

Cheers,
GFS

3rdday · #16 09-21-2011, 02:33 PM

Thanks ALL
My drive is a Bravo I indeed, A Bravo II is capable of swinging 22" Diameter prop. Mine won't do much more than a 15.5. I know Craig Collabella- Collabella Performance, he's an expert at Very High Performance Drives, even the dry sump NXT drives,He used to work out at Lake X, he has helped me, but he presently has no props for me to try. I will try to have the WOT RPMs today.

gofastsandman · #17 09-21-2011, 07:41 PM

The Mirage is 15.380 dia. We`re chasin` `Hoos early Sunday....I could bring the prop.

3rdday · #18 09-23-2011, 04:15 PM

My RATED WOT is 4200-4600, I am Getting 4900-5000RPM WOT
I would like more midrange speed at 2800-3200 RPM, This is where my cruise is. I have been looking all over for the torque Curve on the Carbureted 454, 310 HP engine. Specifically at what RPM is PEak torque? I am looking for Economy and want the benefits of a 4 blade with Bow and stern lift.Can anyone help?

3rdday · #19 09-24-2011, 08:16 AM

Quote:

Originally Posted by zgillies

Hey Brian, when you gonna post some pics of the Amazonian mistress - perhaps you have and I missed the post...

I agree with Steve about the drive but you have the Bravo I and so it goes...

I'd be curious to learn specifically what prop you're running and your performance numbers. How quickly does she get on plane and low low will she hold a plane.

If your PT prop is the MQS series, I think you might just need more pitch. If its not, that model might be the ticket, or maybe the four blade version (MQS4). Get your rpm numbers to WOT with a load and go from there. Try to borrow a Black Max/Diamond (allegedly the same shape as the MQS)in a 17 and 19 pitch and see where you are (they are easy to turn so you might even get up to 15x21). Any shop should have a dozen of those on the wall and be willing to let you give it a go.

Obviously its not the same boat but that geometry totally changed my overall Seafari's performance.

I have often heard it said that the Mirage + is designed to be wound up so I don't think is going to be effective at your target rpms or projected speeds but if Sandy's willing, heck give it a try.

Good Luck

My Model number is M250WBU-15P I am guessing the WBU indicates it is a work Boat, Barge, pontoon boat prop, which is what the powertech folks told me when I emailed them the info.

McGillicuddy · #20 09-25-2011, 12:41 PM

Roger that, Brian.

Sandman's prop might get you where you want to be, certainly closer than the house mouse prop.

Along with the qualities you mentioned, PT Prop describes the OFS series similar to the Mirage.

I think Bigshrimpin mentioned the Mirage Plus works best at higher speed and higher rpm. I don't think you can have that on the 27 w a single 454/Bravo I without cranking up the output. Not sure what year yours is but I've read a few pages that claimed peak torque was achieved at 3800rpm, others @ 4200 rpm. I suppose gear ratio has something to do with that.

The PT Prop MQS 3 blade is a stainless equivalent to the Merc Black Max. They also make a 4 blade MQS.

Without having excess power, I'm pretty convinced there is not a better prop for the SeaCraft hull than the Black Max shape. It probably varies from motor to motor but I'm definitely sold on it.

It's kind of a blend of big round bladed big weight pushers and the more cut and raked speed props.

I'd ask around some other shops for a 15.5 x 17 or 15.25 x 19 Black Max (Merc) or Black Diamond (Quicksilver). Performance guy probably won't have those on the wall because they aren't designed for speed. The Alpha 4 is the Merc 4 blade variant of that shape. Both are all over ebay and CL for less than a Benjamin. Good luck.

P.S. dig that 21 photo!