Core Sound 20 Mark III #16 "Dawn Patrol"

[paul_stewart]

... an untested work in progress ...  

 

Motor mount:

 

 

 

 

 

 

ePropulsion battery in aft locker:

 

 

 

 

"Garage-Top" (26"x25") location for a solar panel: 

 

 

 

 

 

 

Tiller-to-motor  linkage:

 

 

 

 

 

[Alan Stewart]

Looks great! Good job DAD!

[Steve W]

1 minute ago, Alan Stewart said:

Looks great! Good job DAD!

That does look great. I can't see the pic of the garage top. 

[paul_stewart]

[Steve W]

Paul, 

 

That hatch is really nice. I like how you can still have the dodger, solar panel and have the IMHO superior sliding hatch. My kids love to hang their feet in the cabin sitting forward on the cabin top and I like to sand up their captive like a tank commander on the lookout while someone else is at the helm. Well done. 

 

Take Care,

Steve

[paul_stewart]

Boat building  --every choice has pros and cons, everything is an experiment. Here's 2 photos of the hatch parts sliding in graphite-epoxy tracks based on 'research and copy':  I have a huge collection of photos/videos ... of  other boats; such as,  > 200 images from "Carlita", 126 from "Skeena", 60 from "Larissa",  etc.  . . . .   

I appreciate your posted photos and videos!  

 

           

 

    

[AmosSwogger]

Paul, is this how you routed the hoses/pipes for your reversible ballast pump? In the immortal words of Jay, I'm going to R&D (research and duplicate) your setup.  Want to make sure before I start drilling holes.

 

Drawing not to scale (no valves or strainers drawn in); just want to make sure I have the rough layout correct. 

 

 

[Hirilonde]

On 7/11/2024 at 9:16 AM, paul_stewart said:

Boat building  --every choice has pros and cons, everything is an experiment.

 

           

 

 

.........and damned because it is all related.

[Alan Stewart]

That's essentially correct. It also has the ability to passively fill with a valve you open or shut reaching through the tank hatch. That's the red x. Also valves in the locker so you can isolate the tank from locker if a hose fails. All water enters and exits the tank via the trunk hole.  https://photos.app.goo.gl/ov83K1tS2iHf2pEQ9

Im gonna do something similar but utilizing my outboard well in the cockpit i think.

[AmosSwogger]

Excellent.  Thank you.  Good find on that reversible pump.

 

I'll put up some pics and details once I get started for anyone else retrofitting an already built boat. 

[paul_stewart]

Research and Duplicate ....

 

[paul_stewart]

Amos, here's a few views that may help. The last pic is a look up into the CB well at the inflow/outflow pipe.  The next to last pic shows my attempt to isolate pump vibrations from the bulkhead.  There are 3 filters in this system (shown as circles in the diagram). 

 

[AmosSwogger]

Nice work Paul; fun to see the evolution/ improvement of the 20.3 design over the years.

 

I will say that the simple dual Anderson bailer setup has worked pretty well; been using them to fill/empty for a long time now, it's just slow to empty the tank in light wind.  For anyone considering this; this isn't a necessary mod, just a fun one.

[Don Silsbe]

@paul_stewart— Am I understanding this correctly, that the aluminum runner is only attached to the hatch with epoxy?  Also, is there much advantage to adding graphite to the epoxy in this application?  I’ve not yet used graphite.

[paul_stewart]

Yes. It is unnecessary, but there is also fiberglass cloth helping to hold the aluminum onto the plywood panel. 

It is the edge of bare aluminum that slides in the track.  The aluminum is epoxied to the underside of the sliding panel.

 

The aluminum edge slides in a track.  The track is a groove cut into epoxy that was thickened with graphite powder:  the idea being that the graphite might reduce friction of the aluminum sliding in the track.  I do not know if / how much the graphite helps.  It would be interesting to measure coefficients of friction of aluminum sliding on epoxy-with-graphite  vs epoxy-without-graphite.  

 

Oh, it appears that has already been studied:   just google "friction between aluminum and epoxy that was thickened with graphite"   for that information.

 

[Don Silsbe]

Googling…

[Hirilonde]

I would think that the shape of the aluminum where it slides would be very critical regardless of graphite or not. Fair at both ends, smooth round, etc..

[Don Silsbe]

Are the sliding hatches removable for maintenance?

[paul_stewart]

Yes.  The sliding panels can slide out of the tracks when the "garage top" is removed.   The garage top is held in place by a set of port and starboard screws that are thru-bolted into permanently placed rivnuts.