Prop shaft hole question

Designs for inboard or outboard power

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tysman52
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Prop shaft hole question

Postby tysman52 » Sun Jan 15, 2017 9:15 am

Getting ready to drill my Monte Carlo prop shaft hole. I ordered the 15.5 degree strut upon Gayle's recommendation. With this angle, the strut and prop shaft hole cannot both be placed in the same place as the plan describes. So my options are:
1. Place the prop shaft hole where the plan describes and have the strut end up about 6-7 inches forward of what the plan says
2. Place the strut where the plan describes and have the prop shaft hole 6-7 inches more aft than the plan
3. Keep both where the plan describes and shim the strut, changing the angle. (Effectively would decrease the strut angle)

I think I'm leaning towards option 1...thoughts?

I haven't decided on engine/transmission (taking suggestions!) but leaning towards a 350 because of ease of parts/maintenance etc. and more wiggle room with size and installation...I'm not an engine guy and am outside of my comfort zone wrapping my mind around the engine install...but
have been studying Glen's book.

Thanks!
JT

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Bill Edmundson
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Re: Prop shaft hole question

Postby Bill Edmundson » Sun Jan 15, 2017 10:02 am

JT

Before you cut. You may have already noticed this. The keel has about a 2*+/- angle to the engine stringers. That may affect the placement. I might move things back some. All the mahoganies I've seen tend to run a little bow heavy, particularly at low speed.

Bill
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Roberta
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Re: Prop shaft hole question

Postby Roberta » Sun Jan 15, 2017 10:36 am

Bill is right about the angle of the keel reducing the effective angle of the strut from about 15.5 to 13.5 degrees. I would mount the strut per the plans. Another good idea is to offset the rudder to allow easier prop shaft removal. Offset is based on the prop rotation. Offset to port about 1" with right hand prop rotation (Clockwise looking at prop from the stern). I think Gayle guided you correctly. You will be surprised and how close the hole will be to the plan location.

The 350 GM based motors are an excellent choice. The new fuel injected motors are very easy to rig up with either analog or digital systems. Harnesses and diagrams are included with them in the Crusader packages with extension cables optional. They can also make a complete package with transmissions and all the heat exchangers and closed cooling.

Bill is also correct about the woodies being a little bow heavy, so moving the motor back a bit will not be a problem.

Roberta :D
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sscobra
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Re: Prop shaft hole question

Postby sscobra » Sun Jan 15, 2017 2:10 pm

JT, before you do anything, try to find other Monte Carlo builders who have already done this. If you go to the Glen-L website, up near the top of the home page is a heading called "Boatbuilder Blogs". Hover over that with your mouse and another heading will show up called "Project Registry Archives". Click on that and when the page opens you will see an alphabetical listing of all the Glen-L boats. Click on "M" and scroll down to Monte Carlo and you will see seven other builders with their email addresses listed. They could be a real help with your build. That and the people on this forum will be a great help to you. Roberta and Bill have been a great help to me and they know what they are talking about! I am sure other forum members who have built the Monte Carlo will also see your post and offer some help. Skip
Built the Glen-L Monaco, 2016.

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Roberta
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Re: Prop shaft hole question

Postby Roberta » Sun Jan 15, 2017 2:34 pm

Looking at the hardware callout it does say 14 deg strut for the Monte Carlo. Glen L does carry several 14 deg struts. Did Gayle give you a reason to not use the 14 deg strut?

Roberta
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tysman52
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Re: Prop shaft hole question

Postby tysman52 » Sun Jan 15, 2017 5:15 pm

Bill, Skip, Roberta...thanks for the input
Roberta, there is discrepancy between the online instructions, the plans, and the instructions which led me to email Gayle about it. She sent me the 15.5 angle strut
Here is a thread I found where Rick ran into the same problem but looks like he went with a 14 degree

viewtopic.php?f=2&t=5476&p=38470&hilit=Monte+Carlo+strut#p38470

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Roberta
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Re: Prop shaft hole question

Postby Roberta » Mon Jan 16, 2017 8:53 am

Personally, I think with a little shimming on the strut and shaft log, you should be fine with what Gayle recommended and be able to place the strut and prop shaft hole where recommended on the plans. Key things to remember are to keep the rudder under the boat (so the rudder port should be in the proper location) and maintain clearance from the prop to the rudder and hull bottom. Mockups and temporary installations really help.

Roberta :D
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slug
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Re: Prop shaft hole question

Postby slug » Mon Jan 16, 2017 12:01 pm

My preference is to make a full size cut out on cardboard of the engine and transmission and use it to determine the location of the hole. This has worked well for me on the Titan and the Gentry. The cut out shape and sizes are usually available on the installation drawings for the particular motor you chose to use.
Doug

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Jimbob
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Re: Prop shaft hole question

Postby Jimbob » Tue Jan 17, 2017 5:21 pm

Roberta reminded me of what I did when I had to determine where to drill the hole. Starting with the rudder, I determined where the rudder should be making sure that the rudder was not extending beyond the bottom of the boat and that the rudder shaft ended up in the proper place inside the boat. I was afraid that there wouldn't be enough clearance from the true transom. (my boat has a false transom beyond the real one) Next I positioned the prop the correct distance from the rudder and then the strut the proper distance from the other side of the prop. I put the prop on a dowel and inserted into the strut to get the right spacing. I then drilled through the strut, and that's where the hole ended up.

If I had it to do over, I would consider plunge cutting a slot instead of drilling a hole with a bit. I think the slot would give you more leeway.

Jim
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psychobilly
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Re: Prop shaft hole question

Postby psychobilly » Tue Jan 17, 2017 6:43 pm

How much offset do you have to put on the rudder? Is it 1" or 2"? I suppose the shaft size dictates this?

Also, if your wheel swings to the left, is the rudder offset to the right?

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Roberta
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Re: Prop shaft hole question

Postby Roberta » Tue Jan 17, 2017 7:39 pm

I think I put about 7/8" offset on the Torpedo. Roughly half the diameter of the prop shaft and half the thickness of the rudder about where the prop shaft would hit the rudder plus a bit more just for clearance.

Roberta
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