Lee's Monaco utility build

Designs for inboard or outboard power

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Roberta
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Re: Lee's Monaco utility build

Post by Roberta »

Typically, these boats perform best with 1:1 ratios. 1.2:1] will require larger props of greater diameter and/or pitch. 13" props work well with 1:1 ratios. A 14 or 15 might be more suitable with gear reduction. Idle speeds might be unmanageable with high pitched props.

Roberta
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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Bill Edmundson
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Re: Lee's Monaco utility build

Post by Bill Edmundson »

Lee

On the small Tahoe I swing a 13x16 LH prop. I have a 1" shaft. 1.23:1 8* down angle ZF63a gear. I run a 115 HP diesel @ 3800 rpm. She does 38 mph. Great fuel economy. The fuel will never pay for that engine.

I have a left/port helm. My wife wanted it like a car. She's been there once.

The bigger and slower you spin the prop, the more prop walk walk you will get at low speed.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

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kens
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Re: Lee's Monaco utility build

Post by kens »

Bill does well with the 1.23:1 because he has moderate HP installed.
Take the 1.23:1 and add big HP and it becomes a different animal

I have a deep gear, 2:1, but again, I have moderate HP
Put a big HP in my boat and you couldn't make it work

Whats that big Mahogany, Miss Chris? 28-footer?
Now that could take the 350hp and 1.23:1 and use it
Oak..........the juice ain't worth the squeeze :D :shock: :o :)

denbrlr
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Re: Lee's Monaco utility build

Post by denbrlr »

Thank you all for the additional info and thoughts.

Roberta, I think you have me convinced that 1:1 is the way to go and that the Liberty A is the way to go. I saw your comments about it protruding a little lower. I am building a utility version so that gives me a little more flexibility with the height but I still want it as low as possible. I will try to estimate how high my engine will be with the Liberty A.

Bill, It sounds like you have a good setup with your diesel. At lot of low end torque with that one. A lot different than where I am heading :)

Ken, Thank you for our prop discussion on the phone :) and the PM discussion about Dave Lott's prop journey.

Looking through Dave Lott's posts, he ended up with a 13.5x16 prop (he runs a PCM EX343 with their 1.23 reduction trans). In one of his posts he mentioned noticing bottom paint erosion near his prop. His strut has a 7.5 inch drop and that is what the Monaco plans call for. The Monaco plans also call for a 12 or 13 inch prop. His 13.5 inch diameter prop gets his prop closer to the bottom. Glen-L recommends at least 10% of the prop diameter but the further the better. Dave said his clearance was 1.5 inches so he is still within spec. but maybe a 13.5 inch prop was part of Dave's problem. Have any of you noticed prop erosion on the bottom? Have any of you considered attaching some sort of sheet bronze in that area to protect the hull? Please let me know. Thank you.

Lee
YouTube channel: Boat Builder Lee
Monaco build YouTube playlist: https://www.youtube.com/channel/UCP4Edb ... /playlists

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kens
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Re: Lee's Monaco utility build

Post by kens »

One of my prop setups was a 17x14 4blade. I swear I could feel prop tip vibes. It was a high end vibe, but I don't have a frequency counter to prove it.
it was coming from exactly where the tips would be though. that wheel came off anyway it didnt do anything special.
I been working on a donor boat getting many parts off it, like and engine. The owner says he wants to convert to outboards on a bracket because inboards are heavy, slow, gas guzzlers. Well this one anyway, everything you could install wrong was wrong, and, HEAVY. The prop had less than 1/2" tip clearance, and a half goose egg eroded in the hull. Fiberglass must be an full inch thick because the goose egg is 1/2" deep.
But the erosion thing has not been a big subject at the Gatherings, I cannot recall of any erosion problems on this forum.
Oak..........the juice ain't worth the squeeze :D :shock: :o :)

denbrlr
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Re: Lee's Monaco utility build

Post by denbrlr »

I am planning on installing a fin on my Monaco but the plans don't call out the location. I found this comment from another post "Unless the skid fin location is noted in your plans, the fin(s) are installed on the centerline of the hull, at approximately the center of the waterline length". That would put it somewhere between frames 4 and 5 but closer to frame 4 on the Monaco. Does that sound right?

Lee
YouTube channel: Boat Builder Lee
Monaco build YouTube playlist: https://www.youtube.com/channel/UCP4Edb ... /playlists

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Roberta
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Re: Lee's Monaco utility build

Post by Roberta »

I located mine on the centerline just below the engine between frames 3 and 4 on the Torpedo. That's right around 8 feet from the transom. I used the "V" base bronze fin from Glen L. Seems to be fine with no skidding. Boat handles great. The fin was installed during construction, so I can't say if the boat actually needed a fin. Glen did not think it would but said it wouldn't hurt. Your hull is very similar to the Torpedo. Additionally, I countersunk the V base into the hull planking so the base was flush with the planking. I countersunk the rudder port and the prop strut as well.

Roberta
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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Roberta
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Re: Lee's Monaco utility build

Post by Roberta »

Looking back in my records, the front of the fin base was located 86" from the transom.

Roberta
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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Rich Coey
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Re: Lee's Monaco utility build

Post by Rich Coey »

On my Monaco the fin is centered 105" from the transom just in front of the engine. It handles great too.

Rich

denbrlr
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Re: Lee's Monaco utility build

Post by denbrlr »

Roberta/Rich, Thank you for the information. It is good to hear about example locations that have worked well.

Roberta, I was planning on getting that same fin :)

Lee
YouTube channel: Boat Builder Lee
Monaco build YouTube playlist: https://www.youtube.com/channel/UCP4Edb ... /playlists

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Roberta
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Re: Lee's Monaco utility build

Post by Roberta »

Pictures of prop on Torpedo

Roberta
Attachments
20210420_070023.jpg
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Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

denbrlr
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Re: Lee's Monaco utility build

Post by denbrlr »

Roberta,

Thank you for the pics.

Lee
YouTube channel: Boat Builder Lee
Monaco build YouTube playlist: https://www.youtube.com/channel/UCP4Edb ... /playlists

denbrlr
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Re: Lee's Monaco utility build

Post by denbrlr »

I am thinking more about the prop shaft hole. I am thinking of drilling to support a 1.125 inch prop shaft. I might end up going with a 1.2:1 trans so I want to leave that option open. The Inboard Motor Installations book recommends at least a 3/8 larger shaft hole than the prop shaft. I do plan to line it with a fiberglass tube.

Drilling a hole so the resulting ID of the tube of 1.5 inches would make the hole 3/8 larger than the prop shaft. However, I feel like I would like more margin than just 3/8 inch. I know my limitations :) I am not sure I can drill a prop shaft hole precise enough, line it with a fiberglass tube, line up and mount the strut, and get everything to line up and work with an engine/trans installation after the flip. I am guessing I will need to fudge the angle of the prop shaft and 3/8 inch doesn't give me much room to work with. That would only leave 3/16 inch from the prop shaft to the inner wall of the fiberglass tube. Anyone else have these concerns or is it just me?

Lee
YouTube channel: Boat Builder Lee
Monaco build YouTube playlist: https://www.youtube.com/channel/UCP4Edb ... /playlists

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kens
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Re: Lee's Monaco utility build

Post by kens »

we all fret over drilling that hole, you are not alone
you drill the hole for the OD of the fiberglass tube
figure the shaft clearance + wall thickness tube = OD for hole to drill
Oak..........the juice ain't worth the squeeze :D :shock: :o :)

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Roberta
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Re: Lee's Monaco utility build

Post by Roberta »

While some of this won't help you, Lee, but for some, it will provide an alternate method for drilling the prop shaft hole.

Like most everyone on this forum, I also had angst about the "Dreaded Prop Shaft Hole". I had concerns about creating the flat spot to which the strut is mounted before drilling. To ensure the strut was mounted squarely on the keel and the hole properly lined up. I drilled the hole long before the planking was applied. The following link shows and explains the process.

viewtopic.php?f=2&t=25179&start=375

I used a 1-3/4" bit to drill the hole and lined it with a 1-3/4" fiberglass tube with 1/8" wall thickness, leaving me with a 1-1/2" finished prop shaft hole. One thing to remember is that the actual length of the hole is relatively short once the tube is trimmed for the shaft log and to conform with the keel and hull bottom planking. So a slight amount of misalignment of the hole will not impact the path the the prop shaft as it passes through the strut to the transmission . There is a "little" fudge factor. Shaft logs are made with a hose to allow for minor alignment issues and adjustment of engine and transmission mounts will help in aligning the shaft to the transmission. But alignment should be made as accurate as possible.

Check out my link and use what you can. Fear not. It's wood and can be repaired. You will need to scroll through the pages.

Roberta :D
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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