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Alan Stewart

Core Sound 17 Outboard well (short shaft)

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Today I started on an outboard well for our Core Sound 17 'Southbound'. We recently purchased a Tohatsu 3.5 4-stroke short shaft motor from online outboards. The plan is to use the new motor on our currently under construction CS-20mk3 since it was deemed the best fit. That means the 17 needs a bracket or a well and I didn't want to buy or make a bracket particularly. 

 

We previously used a long shaft 2 stroke honda 2.5 but that motor went with a new owner of our Core Sound 20 Dawn Patrol. The long shaft bolted to a bracket whos edge sat above the top of the transom. The new motor must be in a well to reach the water since it's 5" shorter. 

 

I've been breaking in the new motor in a trash can in the evenings and have now 2.5 hrs of time on it below 3000rpm and it purrs like a kitten compared to the old 2-stroke honda.  

 

Here is a link to all the pictures I took today of cutting a fitting the outboard well. 

https://photos.app.goo.gl/dnbRVtpFxNTxV5o16

 

And here are some select shots....

 

I started with a "minimal" 6" wide 6" deep cutout centered on the old outboard position 13 1/2" off the center-line. I chose 15 1/2" above the lower edge of the transom at that point for the height of the cutout and that turned out to be spot on. Not too low that the controls hit the deck and not too high that the lower unit hits the bottom of the boat. It will remain to be seen if the prop is low enough in the water but I'm prepared to live with it. 

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The motor didn't quite fit width wise so the hole was widened 1" inboard. That got her in the hole but the body of the motor hit the corners of the cutout when it was rotated. So the next iteration aimed to widen the hole to correct that. 

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The motor would now rotate in one direction but from the other "preferred" direction the tiller bonked on the inside corner (see below) . So one more iteration was needed. 

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The final cutout was ~12 3/4" wide at the top edge of the transom starting 8" inboard from the sheer. And 11" "deep" fore and aft. 

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Now satisfied with the size of the cutout I installed a beam across the cutout 1" thick and notched it for an existing stiffener. 

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Then I screwed a bottom in up against the lower face of the beam and proceeded to install cardboard hot glue templates for the sides and front panels. 

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The cardboard templates were replaced with the real McCoy (1/4" okume) . The sides and front were marked on the bottom and then the bottom was cut to final shape. 

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Next all was removed and assembled with 3-4 dabs of hot glue to join the parts together. 

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The hot glue assembly was strong enough to round over the exterior edges and sand it all smooth. 

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This assembly was checked for fit back in the boat. 

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Finally (for today) the assembly was taken into the shop the interior edges were filleted and then it was flipped over and glassed. After the glass was cured enough the edges were trimmed and the box placed on a cutting board with plastic to create a mold surface. Then 2 layers of glass were applied onto the mold surface to create flanges that will bond the top edges of the box up against the underside of the fore deck tomorrow. The beam and box assembly will all be installed together and then the deck cutout edges will be rounded over and the inside of the box glassed to the boat and deck. 

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Excellent work.  This is very similar to the set up that i did onmy cs17.  The only issue that i encountered was with the mizzen sheet hanging up on the motor cowl.a ring on a bungie cord helps pull the sheet forward when tacking.

 

 

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The well that I built in Summer Breeze only had one problem. I couldn't tilt the motor up enough for the tilt lock (or whatever it's called) to engage. The powerhead hit the deck before the motor was tilted far enough. I had to make a block to stick between the tower housing and transom clamp to hold it in a tilted position.

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My experience with my CS 20 is that the notch has to be cut deeper into the transom than the shaft length would indicate. The transom lifts in swells and waves and brings the prop up. In flat water it's ok, otherwise I have to keep the boat stern heavy. I don't want a bracket but I may end up doing that.

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The box is in. I pulled it off the mold this morning, scraped all the gluing surfaces, buttered it up and squished it in place. 

 

If the prop ends up a bit too high, I might be able to cut her down a little but the motor body was the limiting factor when the motor swings through 180 degrees. 

 

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Awesome work. Brings back memories of trying to work this out on my CS20.3. The geometry gets pretty tricky on the reverse angle transom.

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Graham pointed out to me that I mistakenly said my old Honda 2.5 motor was a 2-stroke when i should know darn well that Honda is known specifically for NOT making 2 stroke outboards. Allow the record to reflect that it is in fact a 4-stroke and I am working on writing 100 times on the chalkboard. Honda never made a 2 stroke outboard, Honda never made a 2 stroke outboard, Honda never made a 2 stroke outboard, Honda never made a 2 stroke outboard.......

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4 minutes ago, Alan Stewart said:

Graham pointed out to me that I mistakenly said my old Honda 2.5 motor was a 2-stroke when i should know darn well that Honda is known specifically for NOT making 2 stroke outboards. Allow the record to reflect that it is in fact a 4-stroke and I am working on writing 100 times on the chalkboard. Honda never made a 2 stroke outboard, Honda never made a 2 stroke outboard, Honda never made a 2 stroke outboard, Honda never made a 2 stroke outboard.......

Well to be fair, Graham has been known to be wrong  too. IIRC he used to drive on the wrong side of the road as standard practice.

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The mosquitos and I decided the well was nice and strong and just needed some epoxy coats. 

 

Planning to give it a test this weekend. 

20180522_183650.jpg

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   Alan, if your old Honda 2.5 was the one that I sold to Dawn and Paul it wasn't just not-a-two-stroke.  I think it was also only-a-2hp. :)  I may be remembering that incorrectly, though.

   Please post pictures of the trials - I still miss that boat (not that there's much left of the original after your repairs and improvements, mind you).

   And Capt Oyster - I have it on good authority that Graham long ago ceased to drive on the correct side of the road and now is following your example of driving on the right side instead of the correct side.  Wait - That's making my head hurt...  Nevermind.

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Haha, Ken you are right as well it was a 2hp. It served us well and was just sold along with the Dawn Patrol package. 

 

It may not look the same but it's got good bones. 

 

Here are some pictures of us on one of our last years trips out to lookout.  https://goo.gl/photos/DhpTDZTJHqAuzAe79

 

And some shots from one our last years day trips to the sandbar in Beaufort with friends. The masts stayed at home and we went in "motor mode" with beach umbrellas in place of the masts. 

 

20170715_155621.thumb.jpg.fbc5c9f1d922bed0bac97f0f6f63d783.jpg20170715_155713.thumb.jpg.57627fb54d7169e8873d1f8924eda0be.jpg

 

 

 

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Hey Alan, I notice on your posts,

Alan Stewart

Advanced Member

Website

Location North Carolina, Raleigh

Aren't you still in New Bern? Kinda a long drive to work from Raleigh!

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12 hours ago, Ken_Potts said:

He just drives his motor boat down the river every day.

Yeah, but it's the wrong river. He has to drive it down the Neuse River, to the mouth of the Pamlico Sound, and around into the Bay River.

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It seems less wrong than the Ohio river, though...

Thanks for the pictures Alan.  It's nice to know you're still having fun with the boat.

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Outboard well trial by fire. works great. Out on the sandbar near Beaufort ,NC today with good friends, dog, umbrellas and a cooler full of drinks and snacks. What a great day. 

 

20180526_124614.thumb.jpg.3658596a3125d97cb5aaf6dd18844d64.jpg

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20180526_130420.thumb.jpg.64c313161ee3f4f16a610591ab997959.jpg20180526_130521.thumb.jpg.7cd69fd55ecfff50f5646192f1be5362.jpg

 

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For comparison, I am using a Yamaha F5 long shaft 4 stroke (or a Chinese imitation of one) and didn't need to build a cutout. All I did was build an angled timber bracket and attach direct to he transom with through bolts. Seems to work a treat.

IMG_2245.JPG

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