|
|
06-02-2015, 05:22 AM
|
#1
|
Registered User
Country: Denmark
Occupation: Electronic Technician, offshore
Interests: Boats, Cars and MTBing.
Boat make: Phantom 21
Engines: Merc 300xs
Cruising area: Southern Jutland
Join Date: Jun 2012
Posts: 9
|
What gear ratio to chose on P21 with 300xs
Hi All
I´m new in here, have been looking around a bit though .
I´m about to purchase a 300xs for my P21, just sold my Yamaha Vmax 200HPDI.
Was wounding what gear ratio to chose 1,62:1 or 1,75:1 Sports master.
Just want to hear from you guys, what you think would be best for P21.
Thanks
Brgds
Peter
__________________
|
|
|
06-02-2015, 10:22 AM
|
#2
|
Registered User
Country: Belgium
Location: near Ghent
Occupation: engineer
Interests: boating, wakeboarding, snowboarding, fitness
Boat name: Outlaw
Boat make: Phantom 21ft
Engines: Yamaha 200hp
Cruising area: Zele / Kanaal Gent-Terneuzen
Join Date: Jun 2006
Location: near Ghent
Posts: 473
|
subscribing to learn about "why" one would prefer one or the other.
__________________
|
|
|
06-02-2015, 06:17 PM
|
#3
|
Registered User
Country: Denmark
Occupation: Electronic Technician, offshore
Interests: Boats, Cars and MTBing.
Boat make: Phantom 21
Engines: Merc 300xs
Cruising area: Southern Jutland
Join Date: Jun 2012
Posts: 9
|
Thanks for the nice replay Toffy, but didn't really help me much.
|
|
|
06-02-2015, 07:43 PM
|
#4
|
Registered User
Country: Belgium
Location: near Ghent
Occupation: engineer
Interests: boating, wakeboarding, snowboarding, fitness
Boat name: Outlaw
Boat make: Phantom 21ft
Engines: Yamaha 200hp
Cruising area: Zele / Kanaal Gent-Terneuzen
Join Date: Jun 2006
Location: near Ghent
Posts: 473
|
I've googled you this link, which looks interesting. According to this it mainly comes down to turning props in a more market-available pitch range.
http://www.bbcboards.net/mercury-3-l...-62-gears.html
However, I'm sure there must be some impact on acceleration and minimum planingspeed also.
With the 1,62:1 gear the proppelershaft spins faster at a same motor-rpm. (quicker acceleration?)
With the 1,75:1 gear you must turn a larger pitch prop to obtain the same boat-speed (slower acceleration?, more stress on the lower unit?, maybe higher top end due to being more in the peak hp powerband?)
Keep in mind, I don't know sh*t and someone must chip in to back this theoretical stuff up with some first hand practical experience !
I'm just interested in this matter.
Bump +1
T.
|
|
|
06-02-2015, 08:03 PM
|
#5
|
Registered User
Country: Ireland
Location: Dublin
Occupation: Boatbuilder
Boat make: Hydrostream V-king, 650SS OCR ,Ring 21, Ring 18, Phantom 18.
Engines: 300Hp Mercury 2.4, 130 Yamaha, Bridgeport EFI, XR6, Merc 200.
Cruising area: Malahide, Dublin
Join Date: May 2004
Location: Dublin
Posts: 1,803
|
Which is cheaper?
Would depend on what youre using the boat for. But as said, it wont really make much difference, it can be propped accordingly.
But if its top end youre after, you might find you run out of pitch on the 1.75 before anything else. No idea what a 300XS on a P21 will run like. What rpm/ pitch etc.
What speeds, gear ratio amd pitch was your yam?
|
|
|
06-02-2015, 09:40 PM
|
#6
|
Registered User
Country: Denmark
Occupation: Electronic Technician, offshore
Interests: Boats, Cars and MTBing.
Boat make: Phantom 21
Engines: Merc 300xs
Cruising area: Southern Jutland
Join Date: Jun 2012
Posts: 9
|
Thanks Toffy.
Hydrostream
With my Yam I got 70-72mph with a Bblade Blaster 26p Gear ratio was 2.00:1.
|
|
|
07-02-2015, 08:20 AM
|
#7
|
Registered User
Country: UK
Location: Portsmouth
Occupation: Marine Engineer
Interests: everything fast
Boat make: Phantom 28/phantom 18
Engines: 2x Mercury 3.0 225 optimax/yamaha 85
Cruising area: Solent
Join Date: Nov 2005
Location: Portsmouth
Posts: 1,352
|
I would go for 1.62 as its a light boat and you will run 27-28 pitch I think
|
|
|
07-02-2015, 09:51 AM
|
#8
|
Registered User
Country: Belgium
Location: near Ghent
Occupation: engineer
Interests: boating, wakeboarding, snowboarding, fitness
Boat name: Outlaw
Boat make: Phantom 21ft
Engines: Yamaha 200hp
Cruising area: Zele / Kanaal Gent-Terneuzen
Join Date: Jun 2006
Location: near Ghent
Posts: 473
|
Quote:
Originally Posted by Bulibarger
Thanks Toffy.
Hydrostream
With my Yam I got 70-72mph with a Bblade Blaster 26p Gear ratio was 2.00:1.
|
@72mph that would mean only 2,5% slip. I'm nowhere near that slip% with my very similar setup and prop (Signature Eagle 4 26P). Could it be your gearratio is off mate ? I think it should be a 1,86 ?
On topic : whatever gearratio on the 300XS you're gonna chose, you're getting a nice engine/performance upgrade there !
Keep it safe.
T.
|
|
|
07-02-2015, 03:54 PM
|
#9
|
Registered User
Country: Denmark
Occupation: Electronic Technician, offshore
Interests: Boats, Cars and MTBing.
Boat make: Phantom 21
Engines: Merc 300xs
Cruising area: Southern Jutland
Join Date: Jun 2012
Posts: 9
|
Thanks to all, decision made 1.62 it is.
Toffy that's rigth around 2,5 slip. Bobs nose cone installed with low pickup, bullet night at bottom. So unless our garmin gps here in Denmark shows wrong :-).And yes gear ratio is 2.00:1 have had the engine from new.
|
|
|
07-02-2015, 04:46 PM
|
#10
|
Registered User
Country: Sweden
Location: Stockholm
Occupation: Delta powerboats, Dahl Naval.
Interests: Boats, Cars, boats and boats
Boat make: Frodé 23R
Engines: Mercury 200XS
Cruising area: Lake Mälaren
Join Date: Feb 2013
Location: Stockholm
Posts: 248
|
Could be the propp that could be a bit different. Some propps that are 27" could be 27.5 or 26.5 depending on where you mesaure the pitch.
1.62, you wont be need that big propps then
Elk here who has a P21 and 300XS has 1.75 and Amund here had 1.75 on his 250XS and P21. They ran 27" and 28"
|
|
|
07-02-2015, 04:57 PM
|
#11
|
Registered User
Country: Denmark
Occupation: Electronic Technician, offshore
Interests: Boats, Cars and MTBing.
Boat make: Phantom 21
Engines: Merc 300xs
Cruising area: Southern Jutland
Join Date: Jun 2012
Posts: 9
|
There will be a bit of prop testing and so on. Looking forward for it.
|
|
|
07-02-2015, 04:58 PM
|
#12
|
Registered User
Country: Sweden
Location: Stockholm
Occupation: Delta powerboats, Dahl Naval.
Interests: Boats, Cars, boats and boats
Boat make: Frodé 23R
Engines: Mercury 200XS
Cruising area: Lake Mälaren
Join Date: Feb 2013
Location: Stockholm
Posts: 248
|
Oh yes, I have the same "problem" lol. Lots of testing this spring! Gotta love it
|
|
|
07-02-2015, 08:59 PM
|
#13
|
Registered User
Country: UK
Location: Weston Super Mare
Occupation: Electrical Engineer
Join Date: Mar 2004
Location: Weston Super Mare
Posts: 6,351
|
You'll need tabs. Mate had one on his. Ran mid 80's but have to spin a big prop which narrow phantoms don't like.
|
|
|
07-02-2015, 09:36 PM
|
#14
|
Registered User
Country: Belgium
Location: near Ghent
Occupation: engineer
Interests: boating, wakeboarding, snowboarding, fitness
Boat name: Outlaw
Boat make: Phantom 21ft
Engines: Yamaha 200hp
Cruising area: Zele / Kanaal Gent-Terneuzen
Join Date: Jun 2006
Location: near Ghent
Posts: 473
|
Quote:
Originally Posted by Bulibarger
Thanks to all, decision made 1.62 it is.
Toffy that's rigth around 2,5 slip. Bobs nose cone installed with low pickup, bullet night at bottom. So unless our garmin gps here in Denmark shows wrong :-).
|
That's just simply impressive ! What do I have to do to reduce slip% on my Phantom 21ft. I'm at 10% now......
|
|
|
08-02-2015, 02:39 AM
|
#15
|
Registered User
Country: Denmark
Occupation: Electronic Technician, offshore
Interests: Boats, Cars and MTBing.
Boat make: Phantom 21
Engines: Merc 300xs
Cruising area: Southern Jutland
Join Date: Jun 2012
Posts: 9
|
Guess you will have to get a more efficient prop, and spend more time on you lower unit to make the shape better, I used a lot of time to shape my lower unit, if you have a nose cone installed. You properly already have your Bullet height just at bottom V. That worked for me. Good lock.
|
|
|
09-02-2015, 10:10 AM
|
#16
|
Registered User
Country: Sweden
Cruising area: Stockholm
Join Date: Sep 2011
Posts: 25
|
Quote:
Originally Posted by Zander
Could be the propp that could be a bit different. Some propps that are 27" could be 27.5 or 26.5 depending on where you mesaure the pitch.
1.62, you wont be need that big propps then
Elk here who has a P21 and 300XS has 1.75 and Amund here had 1.75 on his 250XS and P21. They ran 27" and 28"
|
Elk runs 1.75 but I ran 1.62
|
|
|
09-02-2015, 10:39 PM
|
#17
|
Registered User
Country: Sweden
Location: Stockholm
Occupation: Delta powerboats, Dahl Naval.
Interests: Boats, Cars, boats and boats
Boat make: Frodé 23R
Engines: Mercury 200XS
Cruising area: Lake Mälaren
Join Date: Feb 2013
Location: Stockholm
Posts: 248
|
Quote:
Originally Posted by Amund201
Elk runs 1.75 but I ran 1.62
|
Oh damn, my bad!
|
|
|
10-02-2015, 04:55 AM
|
#18
|
Registered User
Country: Denmark
Occupation: Electronic Technician, offshore
Interests: Boats, Cars and MTBing.
Boat make: Phantom 21
Engines: Merc 300xs
Cruising area: Southern Jutland
Join Date: Jun 2012
Posts: 9
|
|
|
|
11-02-2015, 09:19 AM
|
#19
|
Registered User
Country: Finland
Location: Helsinki
Interests: Everything fast
Boat make: Hydrostep 650, TG 5000XR, Kimach 450 Speed, Stopper
Engines: Merc 115 ProXS 4S, Merc 60 Formula Race, Yamaha 20
Cruising area: Helsinki
Join Date: Apr 2014
Location: Helsinki
Posts: 67
|
Quote:
Originally Posted by Amund201
Elk runs 1.75 but I ran 1.62
|
Yep. Amunds ex-P21 is currently running a 3-blade 14.75x27" Croxton or a 4-blade 15x26" Hydromotive depending on conditions. 26" runs at just over 6000rpm at WOT and the 27" just under 6000rpm. Both are labbed, so they are not standard off the shelf props. Top speed is around 85-90mph. Current pilot who is still learning the ropes has hit the 85mph mark with the 4-blade, Amund has gone 90mph+ with the 3-blade... and the motor is a 250XS. The P21 is a light weight model, not sure if that has great effect on the numbers or not...
|
|
|
12-02-2015, 07:45 AM
|
#20
|
Registered User
Join Date: Aug 2011
Posts: 87
|
Gearcase
Quote:
Originally Posted by Bulibarger
Thanks to all, decision made 1.62 it is.
Toffy that's rigth around 2,5 slip. Bobs nose cone installed with low pickup, bullet night at bottom. So unless our garmin gps here in Denmark shows wrong :-).And yes gear ratio is 2.00:1 have had the engine from new.
|
Hi Bulibarger,
I have a 1,75:1 gearcase you can try it is brand new
Where in Denmark do you live?
Mvh
Brian k
__________________
|
|
|
|
|
Thread Tools |
|
Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Recent Threads |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|