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Author Topic:   Where to mount engine on transom?

Nevek posted 08-19-2013 03:42 PM ET (US)
When people say " mount the engine 1 hole up", does that mean there will be only 1 set of empty holes above where the bolt goes through the bracket?
Then I was reading:
http://www.whalercentral.com/articles.php?cat_id=10&article_id=82
Does this mean that for the lower holes, there will be zero spots above the bolts? Does that article apply for 15' Whalers?
How many holes up should I mount my Yamaha F60 for my 15' Whaler?
Just want to confirm before I start drilling.
Jefecinco posted 08-19-2013 07:16 PM ET (US)
You shouldn't have to do any drilling. Your hull should have a standard pair of existing holes for mounting the engine. Use those.
tedious posted 08-20-2013 08:09 AM ET (US)
I find the "holes up" terminology a bit confusing myself, but I think the way it works (for motors with 4 top holes) is:
- all the way down (upper bolts in top hole)
- 1 hole up (1 empty hole above the bolts)
- 2 holes up (2 empty holes)
- 3 holes or all the way up (3 empty holes)
On my 15, the original motor was installed with the lower holes drilled at an angle to hit the splashwell, which was the Whaler recommendation at the time. It works fine, but I imagine getting the angle just right is not easy.
Assuming you are installing a decent stainless prop (and you should) you are going to want to mount your F60 a minimum of 2 holes up, so you can use the non-standard vertical spacing (the green holes on the WhalerCentral diagram) and drill the lower holes straight. You may find you need to grind or bend the washers on the lower bolts to fit the curve of the splashwell, but that's no big deal.
The FAQ here at ContinuousWave has some good information on the subject as well.
Tim
jimh posted 08-20-2013 09:47 AM ET (US)
The unit of measurement of engine mounting height is 0.75-inches, which is the hole spacing. This dimensions is often referred to as a "hole". The engine mounting height is measured in units of holes and is measured from the lowest position possible in the upward direction. This is a very simple concept. An engine that is mounted 0.75-inches higher than the lowest possible mounting is said to be mounted "one-hole up."
This is quite a conventional measuring system. First, we define the unit of measurement. Next, we define the direction arrow of the measurement. If you have trouble grasping these concepts, think of someone saying an airplane is at 2,000-feet above sea level. The "2000" is the number of units of measurement. The "feet" is the unit of measurement. The "above sea-level" is the direction of measurement. If you understand this description, you can understand an engine that is mounted "one hole up."
Questions about engine mounting location are commonly asked, so there is an answer for them in the FAQ. See
http://continuouswave.com/whaler/reference/FAQ/#Q8
jimh posted 08-20-2013 09:51 AM ET (US)
The sink-style small splash well on classic 15-foot Boston Whaler boats is a problem for engine mounting because the location of the standard lower mounting hole in the transom will be too low for the splash well. This problem is specifically addressed in the FAQ. See the section which begins, "A fifth workaround..."
This section of the FAQ also references literature from Boston Whaler regarding this problem. That literature has been reproduced here at
http://continuouswave.com/whaler/reference/bulletin84-10.html
Nevek posted 08-20-2013 10:43 AM ET (US)
Thanks everyone,
I ended up drilling the "yellow holes" with no issue. I did have to bend the washers slightly but it looks good. The engine is currently 1 hole up, and after some tests I'll probably put it up another hole.
jimh posted 08-20-2013 03:34 PM ET (US)
What are "yellow holes"? Please explain. I think you are inventing a new term.
Tom W Clark posted 08-20-2013 05:03 PM ET (US)
A Yamaha F60 on a classic 15 foot Whaler should have its motor mounted two or three holes up, not just one.
Nevek posted 08-21-2013 10:03 AM ET (US)
Jim, it's a reference to an article from Whaler Central. Please forgive!
And yes, I plan on moving the engine up 2 or two more holes after I finish rigging everything.

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Author	Topic: Where to mount engine on transom?
Nevek	posted 08-19-2013 03:42 PM ET (US) When people say " mount the engine 1 hole up", does that mean there will be only 1 set of empty holes above where the bolt goes through the bracket? Then I was reading: http://www.whalercentral.com/articles.php?cat_id=10&article_id=82 Does this mean that for the lower holes, there will be zero spots above the bolts? Does that article apply for 15' Whalers? How many holes up should I mount my Yamaha F60 for my 15' Whaler? Just want to confirm before I start drilling.
Jefecinco	posted 08-19-2013 07:16 PM ET (US) You shouldn't have to do any drilling. Your hull should have a standard pair of existing holes for mounting the engine. Use those.
tedious	posted 08-20-2013 08:09 AM ET (US) I find the "holes up" terminology a bit confusing myself, but I think the way it works (for motors with 4 top holes) is: - all the way down (upper bolts in top hole) - 1 hole up (1 empty hole above the bolts) - 2 holes up (2 empty holes) - 3 holes or all the way up (3 empty holes) On my 15, the original motor was installed with the lower holes drilled at an angle to hit the splashwell, which was the Whaler recommendation at the time. It works fine, but I imagine getting the angle just right is not easy. Assuming you are installing a decent stainless prop (and you should) you are going to want to mount your F60 a minimum of 2 holes up, so you can use the non-standard vertical spacing (the green holes on the WhalerCentral diagram) and drill the lower holes straight. You may find you need to grind or bend the washers on the lower bolts to fit the curve of the splashwell, but that's no big deal. The FAQ here at ContinuousWave has some good information on the subject as well. Tim
jimh	posted 08-20-2013 09:47 AM ET (US) The unit of measurement of engine mounting height is 0.75-inches, which is the hole spacing. This dimensions is often referred to as a "hole". The engine mounting height is measured in units of holes and is measured from the lowest position possible in the upward direction. This is a very simple concept. An engine that is mounted 0.75-inches higher than the lowest possible mounting is said to be mounted "one-hole up." This is quite a conventional measuring system. First, we define the unit of measurement. Next, we define the direction arrow of the measurement. If you have trouble grasping these concepts, think of someone saying an airplane is at 2,000-feet above sea level. The "2000" is the number of units of measurement. The "feet" is the unit of measurement. The "above sea-level" is the direction of measurement. If you understand this description, you can understand an engine that is mounted "one hole up." Questions about engine mounting location are commonly asked, so there is an answer for them in the FAQ. See http://continuouswave.com/whaler/reference/FAQ/#Q8
jimh	posted 08-20-2013 09:51 AM ET (US) The sink-style small splash well on classic 15-foot Boston Whaler boats is a problem for engine mounting because the location of the standard lower mounting hole in the transom will be too low for the splash well. This problem is specifically addressed in the FAQ. See the section which begins, "A fifth workaround..." This section of the FAQ also references literature from Boston Whaler regarding this problem. That literature has been reproduced here at http://continuouswave.com/whaler/reference/bulletin84-10.html
Nevek	posted 08-20-2013 10:43 AM ET (US) Thanks everyone, I ended up drilling the "yellow holes" with no issue. I did have to bend the washers slightly but it looks good. The engine is currently 1 hole up, and after some tests I'll probably put it up another hole.
jimh	posted 08-20-2013 03:34 PM ET (US) What are "yellow holes"? Please explain. I think you are inventing a new term.
Tom W Clark	posted 08-20-2013 05:03 PM ET (US) A Yamaha F60 on a classic 15 foot Whaler should have its motor mounted two or three holes up, not just one.
Nevek	posted 08-21-2013 10:03 AM ET (US) Jim, it's a reference to an article from Whaler Central. Please forgive! And yes, I plan on moving the engine up 2 or two more holes after I finish rigging everything.