Classi 15 - motor mounting - Moderated Discussion Areas

  ContinuousWave
  Whaler
  Moderated Discussion Areas
  ContinuousWave: Whaler Repairs/Mods
  Classi 15 - motor mounting

search | FAQ | profile | register | author help

Author Topic:   Classi 15 - motor mounting

tedious posted 09-29-2008 07:55 AM ET (US)
I looked at a couple of 15s this weekend, both with 60s, one Merc, one Mariner. Both motors were mounted using only the upper set of mounting holes. To be more specific, the motors have an upper set of 4 holes spaced at 12 7/8" and a lower set of 4 holes spaced at 9 7/8" (the standard spacings) but the mounting has been done using only the top and bottom holes in the upper set of 4. This gives you 4 bolts, but the bolts on each side are quite close together vertically - looks like about 3".
I am guessing that this was done to keep from drilling below the waterline, which would be needed to use the bottom set. Certainly fewer holes below the waterline is a good thing, and the force on the lower transom when running is a push so there's no problem there. I guess the only unusual stress on the transom might be if you decellerated suddenly, as in running into something.
Is this the way most people mount motors on their 15s? Any concerns about it?
I apologize if this is in the wrong forum or has been discussed before - I did try the search feature but did not have any luck finding this specific information. Thanks.
Tim
Tohsgib posted 09-29-2008 09:57 AM ET (US)
Seen it done before and obviously it is not detrimental or you would see damage from them being there for 20ish years. You can always raise the engine and redrill the right way. Back then people thought all motors should be mounted low.
tedious posted 09-29-2008 08:07 PM ET (US)
Thanks - clearly it is not an immediate problem, or these boats would be having troubles. I would still worry about the transom in the even of an impact, though. I am just wondering if this style of mounting would have an impact on value, or if people have had troubel with this over the long run.
Tim
Tohsgib posted 09-29-2008 08:21 PM ET (US)
Again...if was a long term problem, it would have showed up with your 20 year old mounting...correct?
tedious posted 09-30-2008 07:59 AM ET (US)
Not necessarily - the motor could sit just fine on the transom for those 20 years, and rip clean off the first time you hit a submerged object. I do not think it is a major issue; just would like to find out if mounting this way is a common practice on 15s. Thanks for your input in any case.
Tim
Tom W Clark posted 09-30-2008 12:30 PM ET (US)
That is an unusual, unnecessary and undesirable way to mount a motor to a 15.
If you buy a boat rigged this way, I suggest the lower set of holes in the transom be filled, the motor raised on the transom 3/4" or 1-1/2" and a new set of lower holes drilled in the transom that will accommodate at least the upper set of lower mounting holes on the motor's mounting bracket.
This will allow all four mounting bolts to easily clear the bottom of the splashwell and will make the motor mounting MUCH stronger.
tedious posted 09-30-2008 01:43 PM ET (US)
Thanks Tom - it certainly looked undesirable to me from a strength perspective, so I am interested to have your thoughts on the matter. Bolts 3" apart and then the long lever down to the prop and skeg - doesn't seem right. The ocean is pretty unforgiving so you'd better have all the strength you can get.
Tim
A2J15Sport posted 09-30-2008 10:14 PM ET (US)
The 15' has a unique transom.
One of the reasons I've stuck with OMC products is that they have threaded/tapped holes drilled into the engine bracket (inside) that match "through bolt engines" of OMC's and other makes. All inside the splashwell.
The bracketry on most engines (Japanese excluded) used a standard bolt pattern for many years. I suspect Merc./Mariner adhered to that.
Look on the INSIDE of your engine mounting bracket. You may see two threaded holes. Those are for BW mounting, from the inside of the splashwell.
My, new to me, 1989 OMC 60 HP bolted up perfectly using those threaded holes on the inside of the bracket. Tailor made for a BW.
The original OMC (1975-Johnson-50) Was drilled, specially, to make the bolts come through the splashwell-only. Obviously, that BW dealer (Boston, MA) was on the ball and knew that a "universal" mounting system was close.
Take a look.
tedious posted 10-01-2008 09:32 AM ET (US)
Turns out the FAQ has some information on this:
http://continuouswave.com/whaler/reference/FAQ/#Q8
I had read this previously, but did not relate it to this situation. The boats I looked at appear to have chosen a suboptimal method of dealing with the problem.
Tim
Tohsgib posted 10-01-2008 11:00 AM ET (US)
But again easily corrected.
elaelap posted 10-01-2008 11:35 AM ET (US)
I'm reading this at work so I can't run out and check out my motor, but I know that the Yamaha F60 is mounted 'two holes up' on my 1987 15CC, and the four mounting bolts are normally spaced, two at the top and two at least seven or eight inches down at the bottom of the bracket through the transom at the bottom of the splashwell. I'll take a photo tonight and post. Maybe the transom has been redrilled, but if so whoever filled the original holes did a hell of a job, cuz you can't see a thing.
Tony
tedious posted 10-01-2008 11:52 AM ET (US)
Thanks Tony - that would be very helpful. Inside and outside photos would be great if you can.
Tim
elaelap posted 10-01-2008 11:56 PM ET (US)
Sorry I didn't get to it today, Tim--went cruising with my son and got back late. I'm going out in our partnership 21 tomorrow, but I should be back before dark and I'll try to post a couple of shots.
Tony
tedious posted 10-02-2008 07:46 AM ET (US)
No worries Tony - time with your son is irreplaceable, whereas there'll always be some bonehead like me asking for pictures!
Tim
elaelap posted 10-03-2008 12:01 PM ET (US)
Here you go, Tim. Hope it helps.
http://i22.photobucket.com/albums/b309/elaelap/Motormounting15CC002.jpg
http://i22.photobucket.com/albums/b309/elaelap/Motormounting15CC001.jpg
Tom W Clark posted 10-03-2008 12:21 PM ET (US)
Tony,
Your photos illustrate perfectly how to correctly mount an outboard on this hull and deal with the old mounting bolt holes. [ This is all described in FAQ #8 linked to above. ]
We can see that this hull once used the blind holes common to OMC and Yamaha outboards which allowed motor originally be installed as low as possible and still get the lower bolts to clear the splashwell.
In the photos we can see the old bolt holes filled and the new holes drilled to conform with the industry's standard bolt hole layout except the lower holes are raised 3/4" or 1-1/2".
This allows the motor to be mounted at a more advantageous height while preserving the ability to adjust the height in the future, something than cannot be done with the old "blind hole" layout.
tedious posted 10-03-2008 06:13 PM ET (US)
Thanks Tony - a picture is worth a thousand words, or in this case 2000. It looks like you are mounted in the top hole in the bottom set, and the second to the bottom in the top set, so you could go up one more hole, but not down any - although it certainly looks like it would be simple enough to drill another hole in the bracket if you had to (only once it's off warranty!). Just eyeballing the picture of the inside, seems like you could have gone down one hole lower but then you'd have had to trim one side of the washer flat, or us a piece of flat bar across the two.
Thanks again, really appreciate the pics!
Tim

Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.

Author	Topic: Classi 15 - motor mounting
tedious	posted 09-29-2008 07:55 AM ET (US) I looked at a couple of 15s this weekend, both with 60s, one Merc, one Mariner. Both motors were mounted using only the upper set of mounting holes. To be more specific, the motors have an upper set of 4 holes spaced at 12 7/8" and a lower set of 4 holes spaced at 9 7/8" (the standard spacings) but the mounting has been done using only the top and bottom holes in the upper set of 4. This gives you 4 bolts, but the bolts on each side are quite close together vertically - looks like about 3". I am guessing that this was done to keep from drilling below the waterline, which would be needed to use the bottom set. Certainly fewer holes below the waterline is a good thing, and the force on the lower transom when running is a push so there's no problem there. I guess the only unusual stress on the transom might be if you decellerated suddenly, as in running into something. Is this the way most people mount motors on their 15s? Any concerns about it? I apologize if this is in the wrong forum or has been discussed before - I did try the search feature but did not have any luck finding this specific information. Thanks. Tim
Tohsgib	posted 09-29-2008 09:57 AM ET (US) Seen it done before and obviously it is not detrimental or you would see damage from them being there for 20ish years. You can always raise the engine and redrill the right way. Back then people thought all motors should be mounted low.
tedious	posted 09-29-2008 08:07 PM ET (US) Thanks - clearly it is not an immediate problem, or these boats would be having troubles. I would still worry about the transom in the even of an impact, though. I am just wondering if this style of mounting would have an impact on value, or if people have had troubel with this over the long run. Tim
Tohsgib	posted 09-29-2008 08:21 PM ET (US) Again...if was a long term problem, it would have showed up with your 20 year old mounting...correct?
tedious	posted 09-30-2008 07:59 AM ET (US) Not necessarily - the motor could sit just fine on the transom for those 20 years, and rip clean off the first time you hit a submerged object. I do not think it is a major issue; just would like to find out if mounting this way is a common practice on 15s. Thanks for your input in any case. Tim
Tom W Clark	posted 09-30-2008 12:30 PM ET (US) That is an unusual, unnecessary and undesirable way to mount a motor to a 15. If you buy a boat rigged this way, I suggest the lower set of holes in the transom be filled, the motor raised on the transom 3/4" or 1-1/2" and a new set of lower holes drilled in the transom that will accommodate at least the upper set of lower mounting holes on the motor's mounting bracket. This will allow all four mounting bolts to easily clear the bottom of the splashwell and will make the motor mounting MUCH stronger.
tedious	posted 09-30-2008 01:43 PM ET (US) Thanks Tom - it certainly looked undesirable to me from a strength perspective, so I am interested to have your thoughts on the matter. Bolts 3" apart and then the long lever down to the prop and skeg - doesn't seem right. The ocean is pretty unforgiving so you'd better have all the strength you can get. Tim
A2J15Sport	posted 09-30-2008 10:14 PM ET (US) The 15' has a unique transom. One of the reasons I've stuck with OMC products is that they have threaded/tapped holes drilled into the engine bracket (inside) that match "through bolt engines" of OMC's and other makes. All inside the splashwell. The bracketry on most engines (Japanese excluded) used a standard bolt pattern for many years. I suspect Merc./Mariner adhered to that. Look on the INSIDE of your engine mounting bracket. You may see two threaded holes. Those are for BW mounting, from the inside of the splashwell. My, new to me, 1989 OMC 60 HP bolted up perfectly using those threaded holes on the inside of the bracket. Tailor made for a BW. The original OMC (1975-Johnson-50) Was drilled, specially, to make the bolts come through the splashwell-only. Obviously, that BW dealer (Boston, MA) was on the ball and knew that a "universal" mounting system was close. Take a look.
tedious	posted 10-01-2008 09:32 AM ET (US) Turns out the FAQ has some information on this: http://continuouswave.com/whaler/reference/FAQ/#Q8 I had read this previously, but did not relate it to this situation. The boats I looked at appear to have chosen a suboptimal method of dealing with the problem. Tim
Tohsgib	posted 10-01-2008 11:00 AM ET (US) But again easily corrected.
elaelap	posted 10-01-2008 11:35 AM ET (US) I'm reading this at work so I can't run out and check out my motor, but I know that the Yamaha F60 is mounted 'two holes up' on my 1987 15CC, and the four mounting bolts are normally spaced, two at the top and two at least seven or eight inches down at the bottom of the bracket through the transom at the bottom of the splashwell. I'll take a photo tonight and post. Maybe the transom has been redrilled, but if so whoever filled the original holes did a hell of a job, cuz you can't see a thing. Tony
tedious	posted 10-01-2008 11:52 AM ET (US) Thanks Tony - that would be very helpful. Inside and outside photos would be great if you can. Tim
elaelap	posted 10-01-2008 11:56 PM ET (US) Sorry I didn't get to it today, Tim--went cruising with my son and got back late. I'm going out in our partnership 21 tomorrow, but I should be back before dark and I'll try to post a couple of shots. Tony
tedious	posted 10-02-2008 07:46 AM ET (US) No worries Tony - time with your son is irreplaceable, whereas there'll always be some bonehead like me asking for pictures! Tim
elaelap	posted 10-03-2008 12:01 PM ET (US) Here you go, Tim. Hope it helps. http://i22.photobucket.com/albums/b309/elaelap/Motormounting15CC002.jpg http://i22.photobucket.com/albums/b309/elaelap/Motormounting15CC001.jpg
Tom W Clark	posted 10-03-2008 12:21 PM ET (US) Tony, Your photos illustrate perfectly how to correctly mount an outboard on this hull and deal with the old mounting bolt holes. [ This is all described in FAQ #8 linked to above. ] We can see that this hull once used the blind holes common to OMC and Yamaha outboards which allowed motor originally be installed as low as possible and still get the lower bolts to clear the splashwell. In the photos we can see the old bolt holes filled and the new holes drilled to conform with the industry's standard bolt hole layout except the lower holes are raised 3/4" or 1-1/2". This allows the motor to be mounted at a more advantageous height while preserving the ability to adjust the height in the future, something than cannot be done with the old "blind hole" layout.
tedious	posted 10-03-2008 06:13 PM ET (US) Thanks Tony - a picture is worth a thousand words, or in this case 2000. It looks like you are mounted in the top hole in the bottom set, and the second to the bottom in the top set, so you could go up one more hole, but not down any - although it certainly looks like it would be simple enough to drill another hole in the bracket if you had to (only once it's off warranty!). Just eyeballing the picture of the inside, seems like you could have gone down one hole lower but then you'd have had to trim one side of the washer flat, or us a piece of flat bar across the two. Thanks again, really appreciate the pics! Tim