Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Prop selection

Posted by oldcobia on 05/10/15 - 5:54 PM
#1

Getting close to getting my Whaler 27 W/wd in the water and am looking for prop advise. I have twin Yamaha 250's two stroke that have 3blade 21's right now. They were on the motors when purchased. I know these will be too high pitched. How low would be a good place to start? Thanks

Posted by Phil T on 05/10/15 - 11:51 PM
#2

While we can throw out guesses, to get accurate information, we need more information:

Are the motors mounted at the appropriate height? How many empty holes in the upper bracket?

What is the WOT RPM's of the motors with the current props? At what load?

What is the make and model of the prop you have. Aluminum, Stainless?


Posted by oldcobia on 05/11/15 - 10:18 AM
#3

Props are Yamaha SS, 21 p. Motors are as high as possible on whaler drive. This combo has not been in water yet but with the size and weight of the Whaler 27 FC I feel sure the pitch is too high.

Posted by bwguardian on 05/16/15 - 11:50 AM
#4

You will probably wind up with a Mirage type prop in a 19" pitch. Unless the engines are mounted with larger than normal centers they are probably too high.

Posted by Silentpardner on 05/18/15 - 9:03 AM
#5

Mercury Revolution in 17 pitch is what I use on my Whaler 27FC WD with Yamaha 300's. I am VERY happy with them :) Mount those motors high:)

The boat performed very well with Yamaha 2 stroke 200's and 17 pitch Yamaha Saltwater series 2 3-blade props before I repowered. Motors wee mounted 2 holes up, not highest position.

And I am not guessing, that is real world actual experience. You will wind up with 17 pitch props. :)

Edited by Silentpardner on 05/18/15 - 9:10 AM

Posted by bwguardian on 05/18/15 - 1:37 PM
#6

Silentpardner, the Mirage 19 three blade prop is comparable to the Revolution 17 four blade prop on the same boat. It has been stated the Revolution prop will have a slight advantage. My boat is a WD model but not a FC and with that much weight on the bow you will want a prop that bites like the Revolution or Mirage types.

Posted by Silentpardner on 05/18/15 - 5:29 PM
#7

BWGUARDIAN:

Is your boat a Whaler 27? What manufacturer made your motors? What RPM does your motor/s max out at WOT?

Posted by bwguardian on 05/19/15 - 6:59 AM
#8

Silentpardner, I have what started out as a Whaler 27 with one of the original WD's. I removed the cabin and made a continuous level floor much like the Outrage in smaller vessels or the Guardian in this size. It has a large t-top style hardtop that is 8' by 10.5' so it is not comparable to a FC given the distribution of weight differences. However, as aforementioned, if you were to replace your Revolution 4 17" pitch props with Mirage Plus 19" pitch units your boat would perform about the same. I had a pair of Mercury High Five props on my old 25 Outrage that I loved and wish I could find a pair to try on this one.

Posted by bwguardian on 05/19/15 - 7:22 AM
#9

oldcobia, how far apart are your engines mounted?

Posted by oldcobia on 05/19/15 - 9:11 AM
#10

My Whaler already had engines on it but were removed prior to me getting it so I just used the existing holes. There was a sticker on the WD that gave the C to C mounting distance and it seems it was about 27" but I'm not sure. Anyway they were at that distance as recommended by BW. Thanks for all the input.

Posted by bwguardian on 05/19/15 - 11:34 AM
#11

oldcobia, 26"-28" is typical and I would start at two holes up with a 19" pitch Mirage style prop. You will want a prop that bites well like the Revolution 4 and Mirage Plus props do. I wish you were closer as I have a new spare set of the Mirage Plus 19" props I keep just in case that you could try to get it dialed in.

Do you know what diameter those props are? Are you mounting the motors or having someone do it and will they be mounted to rotate inwards or outwards?

Edited by bwguardian on 05/19/15 - 11:40 AM

Posted by oldcobia on 05/19/15 - 11:59 AM
#12

I have already installed motors, CW on starboard side. Motors are up all the way. I'm not sure of prop diameter but I think they are factory Yamaha props, 21M.

Posted by bwguardian on 05/19/15 - 4:25 PM
#13

oldcobia, I assume by CW you mean clockwise as normally one refers to a CR lower unit which means counter rotating. If this is the case, you installed them rotating outwards...correct?

Posted by oldcobia on 05/19/15 - 5:01 PM
#14

That's correct. When I first put these motors on I had the standard rotation on the port side. I thought I had read somewhere that was the correct way to place them. Then I started asking questions and doing more research and nearly everyone said to put the standard rotation on the starboard side. So I switched them. I'm still not sure if there is a wrong way. I guess it depends on hull design and motor placement.

Posted by bwguardian on 05/19/15 - 5:04 PM
#15

You will get more stern lift with outward rotating props and a tad more speed (which these hulls are not designed for) with inward rotating props.

Posted by bwguardian on 05/19/15 - 5:12 PM
#16

Silentpardner, I see you are here somewhat local. I have the windshield, fiberglass deck, and numerous other parts from the boat if interested...

Posted by bwguardian on 05/28/15 - 8:09 AM
#17

oldcobia, have you had the opportunity to sea trial the boat yet?

Posted by oldcobia on 05/29/15 - 8:37 AM
#18

Not yet, I want to get some epoxy paint on the bottom first.

Posted by matteomariotte on 12/19/16 - 8:09 PM
#19

Hi there, im quit faar from your post but......its time to change my props on my BW27Guardian wd.
My old props was 2 Yamaha 200 dpdi, no bad props but now i want to instal a couple of Evinrude 300 g1.
What do you think about ?

Tks guys

MM