|
Another prop seaker, New F50 on Classic 15'3
|
| Westcoaster |
Posted on 03/28/13 - 9:29 PM
|
Member
Posts: 26
Comments:
0
Joined: 06/12/11
|
Hey guys
i just pulled the origional Evinrude super 55 of my hull
it was mounted a couple holes up, not sure what prop it pushed,i had it off once and couldnt get any info on pitch etc.
Anyways im picking up a new 2012 F50 Tiller model next week
And was wondering if anyone could steer me towards a prop or two, i went with the f50 for a couple reasons, i wanted to save some $ on fuel and i will also be using the motor to troll with a downrigger for salmon here on the bc coast. i guess im looking for an descent prop and dont mind spending the money to get it.
But i dont wanna buy a prop just for trolling reasons, i still wanna have some fun with this great little hull.
Gear ratio is 1.85 and its rpm is 5,000-6,000 as stated on Yamaha's website.
Another question i have is how high up would you suggest i mount it ? 1,2,3 holes or just try and get it roughly 2 " above top of transom.
Cheers
Edited by Westcoaster on 03/28/13 - 9:31 PM |
| |
|
|
| Tom W Clark |
Posted on 03/29/13 - 7:36 AM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
Mount it three holes up and use a 12" x 11" Stiletto Star 3.5
|
| |
|
|
| Westcoaster |
Posted on 03/29/13 - 9:27 AM
|
Member
Posts: 26
Comments:
0
Joined: 06/12/11
|
Thanks for the quick reply
i was wondering, you suggested an 11 degree pitch for this setup, i'm curious as to why all the prop calculators i tried are suggesting 13-14, entered values for the calculators were 50hp @ 5,500rpm, 35-37mph boat speed, 7-10 % prop slip and 1.85 gear ratio.
What really caught my attention was this thread
http://continuouswave.com/ubb/Forum1/...18267.html
He has 1987 15 Sport hull (mine is classic smirk) with a Yamaha F60 four stroke EFI which is basically the same
motor but 10 more hp, yet he is running with an aluminum prop 10 3/4 diameter x 15" pitch
and tops out @ 5,800 rpm. Does the 1 1/4" difference in prop diameter have something to do with it ?
So this has me wondering, since the setup is very similar why such a big difference in prop pitch.
forgive me as i'm new to all this prop figuring , i'm sure there are reasons
why but hope you could elaborate a bit please ?
Thanks again
Edited by Westcoaster on 03/29/13 - 9:34 AM |
| |
|
|
| Westcoaster |
Posted on 03/29/13 - 2:38 PM
|
Member
Posts: 26
Comments:
0
Joined: 06/12/11
|
ok I'm understanding things a little better now, gonna go with what you suggested Tom.
would this work
Stiletto Star 1 Yamaha 40-70 hp 12 x 11 pitch right # 32011 3101883
Edited by Westcoaster on 03/29/13 - 10:30 PM |
| |
|
|
| Tom W Clark |
Posted on 03/30/13 - 7:34 AM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
For those reading this now, or in the future, let me point out that propellers are not generic pieces of hardware that can be described simply by pitch and diameter. Every model of propeller is different and they will not all yield the same calculated propeller slip.
Unlike a basic aluminum propeller, the Stiletto Star will typically yield a calculated slip between 0 and -5 percent. Assuming this boat can go 35 MPH at WOT, a propeller calculator suggests a pitch of about 11 inches, so that is where the recommended size comes from.
A classic 15 rigged with a tiller steer four stroke is going to have a much greater rear weight bias than a Sport 15, and it is going to need all the stern lift it can get, that is why I recommend the high blade area, low rake Star over the Stiletto Triad for this application.
|
| |
|
|
| Tom W Clark |
Posted on 03/30/13 - 7:36 AM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
Propeller pitch is described in inches (a distance), not degrees (an angle).
Pitch is the nominal distance a propeller will travel (excluding slip) in one full revolution.
|
| |
|
|
| Westcoaster |
Posted on 03/30/13 - 2:28 PM
|
Member
Posts: 26
Comments:
0
Joined: 06/12/11
|
As luck would have it my current transom holes are not going to work, i could fill them and drill new holes or maybe use a jack plate, the new top holes would be around an inch from the existing ones, i have more room to work with on the bottom, they would be close to 2" apart if i make the new holes 6.5" center to center from top to bottom using 9 7/8 spacing for the bottom and 12 7/8 for top holes, i think it would work either way as i want to mount the motor 3 holes up anyways.
If i went with a jack plate would a different prop be in order
what do you guys think ?
Edited by Westcoaster on 03/30/13 - 2:33 PM |
| |
|
|
| Joe Kriz |
Posted on 03/30/13 - 2:46 PM
|
Site Owner
Personal Page
Personal Album
Photo Albums
Project Albums
Posts: 11447
Comments:
452
Joined: 03/18/05
|
Why do you have to drill new top holes?
Usually, the top holes are in the correct location.
Only the bottom holes on some installations were not the Standard.
http://www.whalercentral.com/articles...icle_id=82
|
| |
|
|
| Westcoaster |
Posted on 03/30/13 - 5:28 PM
|
Member
Posts: 26
Comments:
0
Joined: 06/12/11
|
Here are some pics to clarify a few things
Here is the old motor, the top holes are 10 1/4" on center
the bottom holes are 8" on center.
now that i'm home again and re-measured everything i won't have much meat between the old bottom holes and where i need to drill the new ones, one of the bottom holes is drilled lower than the other aswell, i have the worst luck with oddities like this.
hope the pics work out ok
http://i67.photobucket.com/albums/h28...30cb73.jpg
http://i67.photobucket.com/albums/h28...5e20b9.jpg
http://i67.photobucket.com/albums/h28...16653e.jpg
http://i67.photobucket.com/albums/h28...a166eb.jpg
http://i67.photobucket.com/albums/h28...da9336.jpg
Edited by Westcoaster on 03/30/13 - 5:31 PM |
| |
|
|
| Tom W Clark |
Posted on 03/31/13 - 7:58 AM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
So, what's the problem? Plug and fill those old holes, drill new holes on the BIA pattern. See this article:
http://www.whalercentral.com/articles...icle_id=82
All large outboards made since the mid 1980s use the BIA bolt spacing, so you're going to have to drill those holes regardless of what motor you use.
Seems silly to me to spend money on a jackplate (which will also not have the right holes) when all you need is some glue and putty. A jackplate is not going to work well for a tiller steered motor even if there was a jackplate that had the right holes spacing.
See this recent discussion of the pros and cons of different ways of dealing with old bolt holes:
http://www.whalercentral.com/forum/vi...d_id=16858
|
| |
|
|
| Westcoaster |
Posted on 03/31/13 - 10:50 AM
|
Member
Posts: 26
Comments:
0
Joined: 06/12/11
|
Ok
i'm going to drill out the existing holes an 1/8" more in diameter
also planning on using West systems epoxy 105 with the 206 hardener
i will wet out the holes then use 404 high density filler to make a thickened batch of epoxy,
after its cured i'll sand, gelcoat,sand,gelcoat,sand the mounting area.
i pondered the idea of epoxy soaked wooden dowells but wasn't comfortable enough with that as all the dowells i found here are softer woods.
I am also going to use a couple thin stainless reinforcement plates maybe 15x12x8" , i just wanna try and even the load and eliminate as much stress as i can on mounting bolt locations.
Cheers
Edited by Westcoaster on 03/31/13 - 10:51 AM |
| |
|
|
| Joe Kriz |
Posted on 03/31/13 - 11:06 AM
|
Site Owner
Personal Page
Personal Album
Photo Albums
Project Albums
Posts: 11447
Comments:
452
Joined: 03/18/05
|
You want to use plywood plugs just like the wood in the transom.
I cut 1/2" plywood plugs to fill my holes using epoxy.
http://www.whalercentral.com/articles...icle_id=62
|
| |
|
|
| Westcoaster |
Posted on 03/31/13 - 11:53 AM
|
Member
Posts: 26
Comments:
0
Joined: 06/12/11
|
Thanks Joe
|
| |
|
|
| Tom W Clark |
Posted on 04/01/13 - 7:27 AM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
No need to make this repair more complicated than it needs to be. Here are a few points I want to make:
NEVER use dowel to plug a transom hole. It will not compress as easily as the transom so when you tighten the motor mounting bolts the dowel can "pop" the repair. Use plugs instead.
You could cut your plugs from plywood like Joe did; nothing wrong with that so long as the plywood is good, but there is no need to use plywood unless that is all you have. I would use a softwood, ideally douglas fir, because back in the day, the plywood in Whaler transoms was made of douglas fir plywood from the PNW.
Strictly speaking, it doesn't matter what specie of wood you use so long as it has approximately the same density and modulus of elasticity. Any softwood would be fine, (most types) plywood would be fine, oak, teak and other hardwoods like that, less so. NEVER dowel. Have I mentioned that before?
The transom of a 15' Whaler is two inches thick. It is made of two layer of 3/4" plywood encased in fiberglass. It is the 1-1/2" thickness of the plywood core than you want to plug with wood so just keep inserting glue covered plugs until you've filled that thickness. Do not worry about over-filling because you are going to re-drill the surface of the holes after the glue is set.
Mask the area around each hole thoroughly so you are only sanding the hole itself; do not get into sanding the whole motor mounting area. All the repair needs is to be, is flush and fair with the surface. Once the motor is mounted, the repaired holes will be completely covered and invisible.
There is no loss of transom strength. Use a backing plate if you like but Whaler transoms are much stronger than most people realize.
|
| |
|
|
| Westcoaster |
Posted on 04/02/13 - 6:56 PM
|
Member
Posts: 26
Comments:
0
Joined: 06/12/11
|
I was able to clean up the the prop from the old motor and read it this time,13 & 1/4 x 17 aluminum,motor was a early 80's 55 Evinrude 2 stroke ( commercial model), it performed well.
What do you think Tom ? Would this change what you think i should try for prop size on the new motor, i know the two are quite different but just wondering with this new info and all.
Thanks again i really do appreciate the help from you guys !
Edited by Westcoaster on 04/02/13 - 6:57 PM |
| |
|
|
| Tom W Clark |
Posted on 04/02/13 - 7:50 PM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
No, your old prop will not going to work. Gear ratios and RPM ranges have a HUGE effect on what propellers you can use.
Though a 55 HP Evinrude two stroke from the 1980s has about the same power as a Yamaha T50 four stroke from 2012, they will use very different props on your boat.
The hub of the old OMC prop won't even fit on the Yamaha T50's propel shaft.
|
| |
|
|
| Westcoaster |
Posted on 04/02/13 - 8:10 PM
|
Member
Posts: 26
Comments:
0
Joined: 06/12/11
|
Using the old prop never even crossed my mind, i just figured knowing how it was proped before may help thats all, i ordered the 12x11 Stiletto and will break the motor in as per Yamaha manual and see how it works out after the first 10 hrs
Hopefully picking up the motor on thursday, chompin at the bit here...
Edited by Westcoaster on 04/02/13 - 8:14 PM |
| |
|
|
| Westcoaster |
Posted on 04/07/13 - 8:01 PM
|
Member
Posts: 26
Comments:
0
Joined: 06/12/11
|
Once i drilled out the old 3/8" mounting holes to 1/2" i was able to have a better look inside and wow is the glass ever thick on the inside of the transom, it measured 7/16- 1/2"
http://i67.photobucket.com/albums/h28...9045ea.jpg
http://i67.photobucket.com/albums/h28...193a6c.jpg
The outside glass was around 1/4"
http://i67.photobucket.com/albums/h28...e76790.jpg
And here are the plugs i made, no marine plywood was available, i have exterior 3/4 fir ply leftover from making a bed frame in my van but didn't like how the plywood plugs turned out, for some reason they wouldn't stay together very well so i cut some from this douglas fir.
http://i67.photobucket.com/albums/h28...c92ae7.jpg
Edited by Westcoaster on 04/07/13 - 8:10 PM |
| |
|
|
| Westcoaster |
Posted on 04/07/13 - 8:50 PM
|
Member
Posts: 26
Comments:
0
Joined: 06/12/11
|
Ok back to the mounting of this motor, with the new motor home now i measured and remeasured everything, i only have 8 1/2" on the inside to work with, from the top cap to where i'm comfortable puting a bolt through, i also read all the faq's from continuouswave on mounting options for shallow splash well whalers/montauk's, lots of information there for sure but the fact remains i don't have many real good options.
I am not going to drill the bottom holes on an upward angle from the outside, something is just not right about that. The best solution seems to be using a spacing of 6 1/2" on center between top and bottom holes, but my mounting options would be limited to 2 or 3 holes up only.
I would have liked to use a spacing of 7 1/4" which would allow the motor to be mounted anywhere from one hole up to 3 holes up, but i just don't see me having the room, i would have to move the top holes closer to the transom cap, they would need to be less than 1 1/2" and then drilling on an upward angle aswell.
How close to the transom cap is too close anyways ?
There is nobody professional around here i would trust with this job, thats why i'm just taking my time patching things up and trying to just do it once the best way possible.
The main reason i would like to have mounting options from 1-3 holes up (7 1/4" spacing) and not just 2 or 3 holes up (6 1/2" spacing) is the fact i plan to mod my f50 to an f60 at some point.
i realize this would mean dialing it in all over again with props etc. and thats fine im just tring to avoid not being able to lower the motor if need be.
But if you guys figure an f60 would end up being mounted 2 or 3 holes up then i'll drill away with 6 1/2" spacing.
I could try for the 7 1/2" spacing but i'm really not interested in having to cut washers in half or bend backing plates etc. but...
Edited by Westcoaster on 04/07/13 - 8:53 PM |
| |
|
|
| dgoodhue |
Posted on 04/09/13 - 9:35 AM
|
Member
Posts: 278
Comments:
0
Joined: 10/04/05
|
You will only need the 2 or 3 hole up positions.
Dave |
| |
|
