Key Largo Build in Charleston

A forum for contacting other builders of Ken Hankinson designs. These designs are now a part of the Glen-L family.

Moderators: Bill Edmundson, billy c

TomB
Posts: 621
Joined: Wed Jan 18, 2017 4:07 pm
Location: Holland, MI

Re: Key Largo Build in Charleston

Post by TomB » Sat Jun 08, 2019 7:34 am

Sometime during the summer I get to say "its not the heat, its the humidity". If we go back in time before plywood when boats were made with planks -

The bottoms where planked close, the cracks sealed with oakum and the builder's secret formula "red lead". They leaked. To solve the problem the boats were lowered into the water and allowed to soak and the planks swelled across their width to form a tight seal between planks, solving the leak problem.

Topsides leaked too. Put the planks together and the wood shrinks when the humidity is low causing leaking gaps. Put the dry planks tight and humidity pushes them apart causing "duck puckers" and eventual fastener failures. The solution was wider joints and caulk.

If you use plywood, the wood grain in each layer is turned to reduce the effects of expansion and contraction. So we wind up with a stable layer, top and bottom of the boat, no more soaking, no topside caulk. Now add a veneer layer, full adhered to the stable substrate (really no different than making a thicker layer of plywood). While a 1/4" veneer might want to move, it can't move at the plywood interface because the plywood won't let it. So how much can the top face of a 2" wide 1/4" thick board expand/contract? Not much. Butt the top planks together, caulk, epoxy caulk, paint stripes on plywood, all good.

There is a gap in my argument at the coverboard topside interface. Since the coverboard is rabbeted and overlaps the plywood layer all the expansion happens away from the topside seam, so that joint can be tight too. Here's a little eye candy to illustrate my point-
Madeleine.jpg
my two cents,

Tom

mickfly
Posts: 80
Joined: Mon Jan 29, 2018 9:19 am

Re: Key Largo Build in Charleston

Post by mickfly » Sat Jun 08, 2019 12:52 pm

Thanks all. The caulking with UV resistance sounds like a winner. Charleston is extremely humid...so maybe an issue with epoxy "caulk". I will have a 1/4 plywood base...and ~5/16-3/8 planks.

mickfly
Posts: 80
Joined: Mon Jan 29, 2018 9:19 am

Re: Key Largo Build in Charleston

Post by mickfly » Mon Jul 29, 2019 8:27 am

Making progress on my Key Largo. I have the front plywood decking in place and have milled all the sapele boards for the deck veneer.

I've also made some progress on the steering. I installed a hydraulic cylinder and just yesterday, drilled out the frames for the hydraulic hoses. The hoses/fittings are rather large and I ended up using thin walled PVC (1 1/2 inch) to accommodate both hoses. The holes are rather large relative to the smaller frame sizes. I wonder if I should put a reinforcing piece around the hole? I was thinking of a roughly 10 inch piece of 1/4 marine plywood glued and screwed? I might also use a 3/4 scab for the frame where the tube ends meet (one pvc length was not long enough), but I could use 3/4 for all frames if the reinforcing is needed? I've seen builds where smaller tubing was used for wiring, with no reinforcement.

mickfly
Posts: 80
Joined: Mon Jan 29, 2018 9:19 am

Re: Key Largo Build in Charleston

Post by mickfly » Thu Aug 01, 2019 12:51 pm

DB482239-17FA-4594-8B61-92B83124FFCF.jpeg
DB482239-17FA-4594-8B61-92B83124FFCF.jpeg
Attachments
4CE1A28B-D822-4F3A-ABCA-3FB619159934.jpeg

User avatar
hoodman
Posts: 2231
Joined: Thu Nov 10, 2011 8:48 am
Location: Lafayette, IN

Re: Key Largo Build in Charleston

Post by hoodman » Thu Aug 01, 2019 5:17 pm

I don't think you need to reinforce those frames. But, that's just my opinion.
Matt

Building a Geronimo......!
viewtopic.php?f=2&t=25139

User avatar
psychobilly
Posts: 1060
Joined: Wed May 12, 2010 3:07 am
Location: Tomball, TX

Re: Key Largo Build in Charleston

Post by psychobilly » Wed Aug 07, 2019 3:01 am

I’m no ENGR but have a watch of this.

https://youtu.be/Z9YMVdE3IRM

JimmY
Posts: 821
Joined: Sat Jul 30, 2016 11:08 am
Location: Brighton, MI

Re: Key Largo Build in Charleston

Post by JimmY » Wed Aug 07, 2019 9:29 am

If the tubes are centered in the frames, you should not have an issue. Most of the stress on these part will be along the edges (Think I-beam). Is the tube securely glued all around to the frame in a tight fitting hole? If so, the tube will take some of the stressed.

If it makes you feel better, I would add a 1/4" reinforcement (circle with a hole in it) to each side of the frame.

Looking good!
-Jim
Nothing says poor craftsmanship like wrinkles in your duct tape!

mickfly
Posts: 80
Joined: Mon Jan 29, 2018 9:19 am

Re: Key Largo Build in Charleston

Post by mickfly » Tue Sep 10, 2019 1:19 pm

Making steady progress on my build. I have all the front deck veneers in place (pictures to follow). I opted against using a zillion staples and went with silicone bronze screws where they hit a batten and temporary screws (3/4 inch drywall screws I had laying around) where they did not. I only used a few raptor staples, set the pressure so the head did not dig too much to reduce sanding.

I have the dash mock up done and installed and will work on the real dash starting tonight. I opted not to use a speedometer because I didn't want the pitot on the transom or worry about a thru hull install for something I don't really need. I'll use my phone or a gps unit to tell me how fast I'm going at X rpm. Instead I got a Faria multi-gauge (tach, alt, fuel) and matching oil, temp, and clock. The last gauge will be a depth gauge, which is critical where I boat.

A question for the forum as I move to the next stage...seat construction and thinking about dropping in an engine...
The plans show a metal angle iron, on both sides of frame 2. I'm assuming this metal bracket is required only on frame 2...as it is not shown on other frames (the wooden frame mounting bracket is show on every frame on the drawings)? I further assume the metal is required to reduce vibration and provide support on the frame (2) that surrounds the shaft.

mickfly
Posts: 80
Joined: Mon Jan 29, 2018 9:19 am

Re: Key Largo Build in Charleston

Post by mickfly » Tue Sep 10, 2019 1:26 pm

First half of deck veneer...
Attachments
deck veneer .jpg
First half of deck veneer

User avatar
Bill Edmundson
Posts: 11605
Joined: Wed Nov 23, 2005 6:45 am
Location: Birmingham, AL, USA
Contact:

Re: Key Largo Build in Charleston

Post by Bill Edmundson » Tue Sep 10, 2019 2:50 pm

Looking good. About time to use up a bunch of scrap making bungs.

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

Hercdrvr
Posts: 947
Joined: Mon May 11, 2015 12:52 pm
Location: McKinney TX

Re: Key Largo Build in Charleston

Post by Hercdrvr » Tue Sep 10, 2019 9:36 pm

Very nice, how thick is your decking, 1/4”?
Matt B

mickfly
Posts: 80
Joined: Mon Jan 29, 2018 9:19 am

Re: Key Largo Build in Charleston

Post by mickfly » Wed Sep 11, 2019 12:22 pm

The cover board was about 3/8 proud of the plywood decking, so the planking ended up at 5/16...to reduce the amount of shaping required! I got a thin kerf blade for my table saw... and was able to get three pieces of 5/16 from a 5/4 board. This allowed for a pretty good color and grain match as I coded the pieces as they came off the board(s). I do wish my band saw was "up" to the task of resawing, but I've not been able to get it to work to my advantage...so I made the table saw work.

I am going to have to go into "bung mode" soon.

User avatar
kens
Posts: 4708
Joined: Wed Nov 12, 2003 5:25 pm
Location: Coastal Georgia

Re: Key Largo Build in Charleston

Post by kens » Thu Sep 12, 2019 9:40 am

The thinnest kerf on a table saw I got was to use a skilsaw blade, 7 1/4" blade, thinnest kerf for that size.
depending on the thickness required you may still get enough depth of cut.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

mickfly
Posts: 80
Joined: Mon Jan 29, 2018 9:19 am

Re: Key Largo Build in Charleston

Post by mickfly » Mon Sep 16, 2019 5:23 am

A question I asked in a previous (long) post.

The (Key Largo) plans show a metal angle bracket, on both sides of frame 2. I'm assuming this metal bracket is required only on frame 2? ...as it is not shown on other frames in the plans (the wooden mounting brackets on the motor stringer is shown on every frame, in the drawings)? I assume the metal is required to reduce vibration and provide support on the frame (2) that surrounds the prop shaft?

Tony Hain
Posts: 374
Joined: Fri Aug 26, 2011 3:01 pm
Location: Queensland Australia

Re: Key Largo Build in Charleston

Post by Tony Hain » Mon Sep 16, 2019 11:15 am

Hi,
I assume you may find you have to cut away some of that frame to have clearance for your prop shaft or sump of the motor. I did on the Tahoe. The angle iron is to reinforce that cut down frame.
Attachments
P1010943.JPG
Tony Hain
"Never under-estimate the bounds of human stupidity" (Robert Heinlein)
and on a more optimistic note "nor the capacity for human brilliance"

Post Reply

Return to “Hankinson designs”