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Staffan Berg
07-02-2002, 03:06 PM
After 2 years of restoring my Magnum 27 Sport I need some advice from you out there.
The engine is a single Mercruiser 496HO (425HP)

I need som advice on propeller selection.

If you are interested, there is a picture on
www.plutosystems.com/magnum.htm (http://www.plutosystems.com/magnum.htm)
Dont know how to include a picture in this message.

Sagbay32
07-02-2002, 07:21 PM
Beautiful boat!
Gotta love that hull!

G - FORCE 88
07-02-2002, 07:26 PM
Sweet boat! What kinda rpm's are you running at WOT? Speed? What prop do you have right now? Gear ratio? WHat kinda water you running in? Weight of the boat? LET me know and ill see if I can help someway.
Jon eek! eek!

Digger
07-03-2002, 09:43 AM
gorgeous boat Staffan!

Staffan Berg
07-04-2002, 05:53 AM
Thank you all for your interest.

The prop I have tested is a Mirage 25 Plus.
The engine performs like
WOT = 4.000 rpm
MPH = 50

I have problem to get the boat up on the water.
When I use the powertrim - I cannot lift the boat. What happens when I use the powertrim is that the propeller(not the hull) rises from the water.

I will changed the propeller today.
I try a Bravo 1 24 P.

Thanks again all of you.
(I am an old 22 Classic owner and I have been "listening" to your talk for years)

Staffan Berg
07-04-2002, 05:56 AM
Sorry Jon - I forgot the following
Gear ratio? 1:50
WHat kinda water you running in? Mostly flat water
Weight of the boat? I guess about 2000 lbs

Staffan Berg
07-04-2002, 12:44 PM
Sorry again
The weight is about 2000 kilo.

Staffan Berg
07-06-2002, 12:21 PM
Just testing if I can include a picture in this message.
http://www.plutosystems.com/magnum3.htm

If any is interested. The prop Bravo 24 made 4100 rpm and a 53.4 mph.
I beginning to think that I have to raise the stern drive. (x-dimension)

A simular boat whith the same engine performs like:
RPM = 5100 with a Mirage 25 Plus and makes 65 mph.
It has 3 inch higher x-dimension but he is having trouble in ruff water. (the prop is cavatating=??)

Staffan Berg
07-06-2002, 12:28 PM
http://www.plutosystems.com/images/instrument.jpg

Gearhead99
07-07-2002, 06:55 AM
Nice, Very nice.

Tomahawk
07-07-2002, 07:04 AM
Staffan - at 4000 rpm, you are substantially overproped. Try a Mirage 23" or even a 21". I am assuming you you should be at about 4800 to 5000 rpm. Nice boat, by the way.

Forrest
07-08-2002, 11:17 AM
Staffan - fantastic job on your Magnum! I'm with Tomahawk on this one. Try a 21" or 23" pitch prop so the engine can develop the its maximum power. Also, be sure to check the hull bottom for irregularities - especially the surface between the lifting strakes. A higher X may help somewhat, but not another 1000 rpm and 15 mph.

Also your Magnum 27 may weigh close to or more than 2500 kg (5000 lb) wet.

This guy did the same single engine conversion to his Magnum 27 which he now races (http://www.teamvixenracing.com/).

Dave911
07-10-2002, 03:05 PM
Fantastic boat. Keeps the classic lines with some modern touches. Sorry I can't help with the prop, but I'm very interested in the windshield. Got any contact info??? Thanks.

Staffan Berg
07-10-2002, 03:29 PM
Thanks.
The windshield is just a copy of the original.
It is made of plexi-glass. Done by a a proffesional plexi-company in Sweden.

Forrest
07-15-2002, 04:21 PM
Staffan - how did you get the Magnum Marine logo on the instrument panel? Nice touch!

Staffan Berg
07-16-2002, 03:09 AM
Forrest
I mailed Magnum Marine and asked if they could mail me the logo.
They replied with a web-adress and included a userid & pw so I could download the logo.

Then a friend of mine made some adjustments to the logo so it could be used in a cad-maschine.

Then the logo was cut out from the plexi-glass and filled with white color.

Total cost was 30 dollars.

I got the logo if you want it. To use it you need some design-software that can handle the logo.
Could not be a problem for you !

By the way
The Mirage 23 prop makes 4500 rpm and 53 mph.

I have heard of a company called Hydro Motive that makes propellers in USA. I will get in touch with them.
They have propellers for boats with high x-dimensions. I need to do some work on this problem next winter.

Forrest
07-16-2002, 10:52 AM
http://www.hydromotive.com/

on_plane
07-31-2002, 07:32 AM
Staffan,
I just sent you a private message.