Kathryn by Mahuna - FINISHED - 1:32 - Skipjack Based on HAER Drawings

[Omega1234]

Hi Frank

 

You're off to a cracking start, I see. Precise and methodical as expected!

 

Cheers

 

Patrick

[thibaultron]

Does anyone know if there is a difference between the 1970s and 2005 issues of this book?

[Mahuna]

9 hours ago, Omega1234 said:

Hi Frank

 

You're off to a cracking start, I see. Precise and methodical as expected!

 

Cheers

 

Patrick

 

Thanks, Patrick.  It's great to finally get started on the build after lots of planning and drafting.

[Mahuna]

1 hour ago, thibaultron said:

Does anyone know if there is a difference between the 1970s and 2005 issues of this book?

Hi Ron

 

I have the 2005 version, and in the forward the writer mentions that Burgess originally intended 2 books - part 1 and part 2.  Part 1 was the book published in 1975.  His widow and his son decided to publish the photos intended for book 2 in an expanded version of the original book, which became the 2005 version.

[thibaultron]

Frank;

OK, buy the new version, thanks!

[Mahuna]

Part 5 – The Stem Knee, Keel, and Worm Shoe

 

The stem knee supports the inner stem, has a 5” square socket to support the Sampson Post, and has a mortise on each side for the foreward-most frame.  The following photo shows the stem knee drawing, which was mirrored for aligning the two sides of the knee.

 

                                  

 

A small chisel was used to cut the socket and the frame mortises into the stem knee.  Because the knee was fairly small, I used the work setup shown in the following photos.

 

 

A 5” x 5” strip was used to check the accuracy of the socket for the Sampson Post.

 

 

The stem knee was then glued in place.

 

 

The rest of the keel (aft of the centerboard slot) was installed as two pieces.  The first piece was installed at the beginning of the curve in the keelson.

 

 

The aft keel piece was formed from 3 separate timbers.

 

 

This aft piece was then glued in place.

 

 

This completed the Keelson/Keel assembly.

 

 

There is a ‘worm shoe’ installed under the keel, as a protection for the keel.  This is made from pine and is only 2 “ thick.  The following photo shows the worm shoe being installed.

 

 

The cutwater and outer stem were fabricated, but only temporarily installed at this point.  The outer stem will cover the plank ends, and will be tapered from the planks down to the width of the cutwater, so this work will be left until the planking is installed.  The profile of the outer stem has been cut, and holes have been drilled to allow the outer stem to be temporarily mounted to the inner stem.  In addition, a slot was milled in the forward face of the outer stem for installation of the cutwater.

 

 

 

The following photo shows the completed Keelson / Keel / Stem assembly, with the temporary installation of the cutwater.

 

 

And, finally, mounts were created to keep the keel assembly at the proper height from the shipway, and the assembly was mounted to the shipway.

 

 

With the assembly now mounted in place, it’s time to start making and installing the frames for Kathryn.

 

Thanks everyone for following along, and especially for the Likes and comments.

[Omega1234]

Hi Frank

 

You're never one to disappoint!  Such meticulous and accurate work....well, it's akin to building the full sized ship!  Perhaps you were a shipwright in a previous life?

 

All in all, mighty fine work.

 

'Cheers

 

Patrick 

[Mahuna]

11 hours ago, Omega1234 said:

Hi Frank

 

You're never one to disappoint!  Such meticulous and accurate work....well, it's akin to building the full sized ship!  Perhaps you were a shipwright in a previous life?

 

All in all, mighty fine work.

 

'Cheers

 

Patrick 

Thanks Patrick!  I really do enjoy the challenge of trying to build the model the way the full-size vessel was built - but I think you seem to enjoy the same thing on your models.  When I get to the planking stage I need to determine how much of the work to show, or maybe just cover it all up.

[Omega1234]

Hi Frank

 

If it's any consolation, I'm with you about the planking.  However, my thoughts are that it's sacrilege to put so much work into something that may never be seen.  Leaving the hull and deck partially open seems to be the only way to go.

 

Well, that's my opinion anyway.

 

All the best!

 

Cheers

 

Patrick

[Deperdussin1910]

Great project!

 

I've raced with the skipjacks at Deal Island.  I'm tied between two of them in the photo.  Fun times!

[captainbob]

Well done Frank.  The keel is laid, time to celebrate.

 

Bob

[druxey]

Thank you for my Saturday smile, Frank. Beautifully done.

[Mahuna]

Thanks Bob and Druxey.  This part went fairly quickly and smoothly - the tricky parts will be coming up.

[Mahuna]

5 hours ago, Deperdussin1910 said:

Great project!

 

I've raced with the skipjacks at Deal Island.  I'm tied between two of them in the photo.  Fun times!

Thanks!  You fit in very nicely with the skipjacks.  I envy you and would love to get to the skipjack races some day.  It's a great photo and shows how the boom sags - I'll have to remember that when I get to that point in the build.

[Jack12477]

25 minutes ago, Mahuna said:

 It's a great photo and shows how the boom sags -

Oh shucks, I could have used that warped dowel that came in the kit after all instead of replacing it. The boom would have then had a "natural sag".

[Dansweeney]

So enjoyable watching this progress Frank !

[Mahuna]

18 hours ago, Dansweeney said:

So enjoyable watching this progress Frank !

Thanks Dan!

[Mahuna]

Part 6 – Shipway and Mounting

 

It’s been a little while since the last post – due to some challenges.

 

In the last couple of posts I’ve shown the model shipway for Kathryn in use, but haven’t described it in any detail.

 

The shipway is constructed using a 12” x 48” x ½” melamine shelf, routed to take the Veritas T-Slot Tracks from Lee valley.  These tracks allow the use of the ½ thick shelving – other tracks would require a thicker board.  This is the same arrangement as used on the Dunbrody build, but is based on a longer shelf since Kathryn will be longer than the Dunbrody sectional model.

 

 

The devices at each end of the shipway are the jigs used for holding the centerline, and are the same as used in the Dunbrody build.  The other fixture in the center of the shipway is a jig used for setting the frames – it’s the same jig as was used for Dunbrody, but will be used in a different manner.  Its use will be described in a future post when frame installation is covered.

 

Kathryn is mounted using bolts that run through two spacers that were cut to hold the model at the proper angle.  The initial intent was to thread the shoe/keel/keelson combination to hold the mounting bolts to the hull.  However, when I started mounting the frames it became apparent that the model would need to be frequently removed from the shipway during the framing process.  Obviously the threaded holes in the wood components would probably not stand up to frequent jostling, so a different approach was needed.

 

Since there was no longer any way to embed a nut in the keelson, as had been done on Dunbrody, I needed to find a way to embed a threaded sleeve through the very narrow keel (8”, or ¼” at scale).  I decided to use an 8-32 pronged t-nut as shown in the following photo.

 

 

 

The entire flange needed to be ground off, so a method of holding the nut during grinding was needed.  The nut was screwed onto 8-32 threaded rod, which was held in a large pin-vise.  Two hex nuts were used to keep the t-nut from turning during grinding.

 

 

The flange of the t-nut was then ground away using a bench grinder.

 

 

The following photos show a threaded sleeve after grinding was completed, and both sleeves screwed onto the mounting rods ready for installation.

 

 

 

A #7 drill was the largest drill that could be comfortably used to enlarge the holes in the keel, so the sleeve needed to be further ground to fit into the hole.  The sleeves were then epoxied into the keel.  The mounting bolts can now be removed without any risk to the screw thread within the keel/keelson.

 

With the mounting work now completed framing can begin and will be the subject of the next post.

 

Thanks everyone for following and for the continued encouragement.

[Mahuna]

Part 7 – Frames

 

 

The HAER documentation says that Kathryn’s frames are ‘highly irregular’, rather than giving dimensions.  After measuring the frames in several of the drawings I decided to use a sided dimension of 4” and a moulded dimension starting at 5” at the sheer and increasing to 8” for most frames.  This makes the frames of the model 1/8” thick, and varying from just over 1/8” to ¼” in the moulded dimension.  All frames are single frames, so on the model they will be quite fragile until supported by the interior and exterior planking and other components.

 

 

Since Kathryn’s sides and bottom are flat, there are no curves to contend with in the frames – other than the rounded chine.  The following is the drawing for frame 12 – the forward-most square frame:

 

 

 

Pin-indexing is used to ensure the pieces of the frame line up with the drawing.  EdT in his Young America build log gives a good description of pin-indexing, and I also included it in my Dunbrody build log, so I won’t go into a lot of detail here.

 

Individual frame pieces as well as the pinning template for the frame are marked using a prick punch

 

 

 

And are then drilled using the Sensitive Drilling Attachment on the milling machine.

 

 

 

The frame pieces are then trimmed to the printed lines using the disk sander.

 

 

 

The frames will be very delicate, and there won’t be much glue surface keeping the frame components together or keeping them attached to the keelson, so some additional reinforcing is required.  The frames will eventually be secured to the keelson with structural bolts, and the joint of the frame pieces will be reinforced by dowels, so pilot holes need to be drilled.  The holes for the structural bolts are at an approximate 45 degree angle, so these holes need to be started with a center drill as shown in the following photo.

 

 

 

The pilot holes are then drilled in the frame components.

 

 

 

The drill used for pin indexing is a #63 drill, and the best approach is to use the sensitive drilling attachment for this drilling.  However, the drill used for pilot holes for the reinforcing bolts and dowels is a #55, and the best approach for this drilling is to use the z-axis hand-wheel to get sufficient force in the drilling.  This would normally mean constant changing of drills and chucks, but I’m fortunate to have another solution in my shop.

 

 

I’ve tried miniature drill presses, but have not been happy with the ‘less expensive’ options (less expensive until an x-y table is added).  Recently, Sherline offered a discount on the milling column for the lathe.  This attachment serves very nicely as a second drilling station (or mill if necessary), so I now have the sensitive drilling attachment with the #63 drill in the milling machine, and a chuck with a #55 drill in the milling column on the lathe and have no need to change drills or chucks in the middle of the process.

 

 

 

Constructing the frame consists of aligning the pieces by laying the bottom piece on top of the side piece (using the pins for alignment)

 

 

 

Then using a hobby knife to mark the joint on the side piece of the frame.

 

 

 

After the side piece is trimmed to fit using the disk sander, the pieces are then glued in place and left to cure.

 

 

 

When the gluing is completed, the hole for the reinforcing dowel is drilled into the side piece of the frame.

 

 

 

The dowel is glued into the frame and clipped off.

 

 

 

Since the frames are mortised into the keelson on each side, aligning the frame on the keelson requires that each side is aligned separately to allow for possible mis-alignment of the mortises.  A jig is used for this purpose.  This is the same jig that was used to align the Dunbrody frames.

 

 

 

In addition to the jig, a template for the frame, consisting of the frame drawing cemented onto a flat piece of 1/16” thick basswood, is clamped to the framing jig and aligned with the centerline.

 

 

 

 

 

The frame piece is clamped to the framing template while the glue attaching the frame half to the keelson cures.

 

 

 

 

The same process is followed for the opposite side of the frame.  The following photo shows the first frame (#12) installed.  Only 25 frames to go.

 

 

 

One last item:  I wanted a modeling setup that would allow me to work on all sides of the build without turning the shipway.  It would also be ideal if I could raise or lower the model depending on what was being worked on at the time.  I was able to find an adjustable table in IKEA – known as a Skarsta sit/stand table.  Using a simple hand crank, the table extends from a minimum height of 27.5”

 

 

 

to a maximum height of 47.25”

 

 

 

 

My old back is very grateful for the working height!!

 

 

 

 

Thanks everyone (and thank you IKEA!)!

[russ]

Frank:

This is a good looking boat. Very good subject matter. I like the system you are using for framing.

 

Russ

 

 

[albert]

Great beautiful work Frank.

[mtaylor]

Very nice work, Frank.  And I love that table.  It's got me thinking....

[druxey]

Beautifully and methodically described and done, Frank.

[Canute]

Nicely done Frank. And good clear explanations, too. Like Mark says, that table is interesting.

[Mahuna]

Thanks Russ, Albert, Druxey, Mark, and Ken for the encouragement.

[usedtosail]

Happy Birthday, Frank.

[Omega1234]

Hi Frank!

 

Happy Birthday to you!

Happy Birthday to you!

Happy Birthday to you!

 

Have a great day.

 

Cheers

 

Patrick

[EdT]

Terrific work, Frank.  Its great to see some of these methods applied to a completely different type of hull structure.  Two Sherlines!  This is serious mobilization.

 

Ed

[Mahuna]

Thanks Tom and Patrick for the birthday greetings.  Had a great day.

 

1 hour ago, EdT said:

Terrific work, Frank.  Its great to see some of these methods applied to a completely different type of hull structure.  Two Sherlines!  This is serious mobilization.

 

Ed

 

Thanks Ed.  The combination makes the drilling much easier.

[popeye the sailor]

nice looking ship yard and really great progress.