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

[Mahuna]

10 hours ago, HIPEXEC said:

I also think you could patent your shipyard. Amazing

Thanks Rich, but my shipway is copied from some other modelers' approaches, so I think that wouldn't work.

 

8 hours ago, Omega1234 said:

Hi Frank

 

Congratulations on completing this part of the framing.  A milestone, that's for sure.  I've always liked the shape of Skipjack hulls and seeing Kathryn, in her present unplanked state, only reinforces that sentiment. 

 

She's a beauty.

 

Cheers

 

Patrick

Thanks Patrick.  It's a good feeling getting to this point.  Now I have to work on some of the more difficult parts.  

 

2 hours ago, druxey said:

Lovely work so far, Frank. I still can't get over the light scantlings of those frames!

Thanks Druxey.  It's amazing to think that Kathryn survived over 100 years before the recent major reconstruction.  So many younger skipjacks have already rotted away.

 

1 hour ago, cwboland said:

Hi Frank

Been silently following along and am just amazed at how tiny all those frame pieces are. You must talk with Igor and get some of his giant matches for comparison 😆

Glad to hear from you Carl.  I'm not sure what matches you're referring to - I'll have to look for it.

[thibaultron]

The frames were out by 1/16", or 2" in real life. I don't doubt that this may not have been true on the real boat, and probably fixed in much the same way.

 

Years ago while living in MD. I read an article on a local large wooden boat builder, one of the last in the area. He said that all the boats he built, and all of the ones he knew about were asymetriacal by a fair amount, that modern ship builders would be surprised by. The nature of wood construction.

[Mahuna]

1 hour ago, thibaultron said:

The frames were out by 1/16", or 2" in real life. I don't doubt that this may not have been true on the real boat, and probably fixed in much the same way.

 

Years ago while living in MD. I read an article on a local large wooden boat builder, one of the last in the area. He said that all the boats he built, and all of the ones he knew about were asymetriacal by a fair amount, that modern ship builders would be surprised by. The nature of wood construction.

Thanks Ron. You've made me feel better 😊  

[PETERPETER]

You said you would finish the frames this weekend and by golly you did. I am still wanting to understand how the frames were fastened to the keel after being slotted into the mortises. 

Your encouragement finally has me back to work on Willie Bennett. The plans have a tremendous amount of detailed I not did recall, having last worked on her years ago. The work I did then passes my scrutiny. I finished the woodwork and iron fittings on the bowsprit today and I will be able to show some progress at our next meeting. Thanks for your help.

Peter

[Mahuna]

3 minutes ago, PETERPETER said:

You said you would finish the frames this weekend and by golly you did. I am still wanting to understand how the frames were fastened to the keel after being slotted into the mortises. 

Your encouragement finally has me back to work on Willie Bennett. The plans have a tremendous amount of detailed I not did recall, having last worked on her years ago. The work I did then passes my scrutiny. I finished the woodwork and iron fittings on the bowsprit today and I will be able to show some progress at our next meeting. Thanks for your help.

Peter

 

Hi Peter - so glad to hear that you're making progress.  Your excellent models are a major reason I started scratch building, and I value your friendship.

[Mahuna]

Part 11 – Stern Construction

 

In preparing to work on Kathryn’s stern, I used the HAER drawings and photos from the recent reconstruction.  These documents and photos raised a lot of questions about how this area was configured in the original construction, and also some questions on how to translate that to the model.

 

The HAER documentation for Kathryn describes her construction as “Her rudder post is forward of the transom, a feature called an “inboard rudder” on skipjacks.  She has a fully framed bottom with fore-and-aft planking.”

 

The following photos show Kathryn’s stern before the reconstruction effort began.

 

                        

 

                        

 

The HAER drawings show a profile view and a top view of Kathryn’s construction.  The following is the relevant part of Sheet 4, showing the profile view of Kathryn’s stern construction.

 

                        

 

As can be seen in the photo, the stern timbers are somewhat curved, and are attached to a strongback that is installed behind the last frame and is attached to the end of the keelson. 

(This points out an error I made in the keelson construction: I left the end perpendicular, rather than slanted as in the drawing.  This was a conscious decision, since I thought it wouldn’t be an issue, but I’m beginning to rethink that decision.  I may decide to install a small wedge to give the strongback the required slant.)

 

The top view from Sheet 5 shows more of the construction detail.

 

                        

 

There are a total of 8 stern timbers shown, 6 of which are attached to the strongback.  The two central stern timbers flank the rudder box, and the next two timbers on each side appear to be evenly spaced, while the outermost stern timbers are spaced somewhat closer to the adjoining timber. 

 

The lines plans from the HAER documentation (Sheet 2) don’t show any of the stern timbers, so I added them when I redrew the plans for the model.

 

                        

 

The outermost timbers are not attached to the strongback, and I haven’t been able to determine how these two stern timbers are supported.  The following photo from the reconstruction seem to show the old timbers, and it can be seen that these outermost timbers support the end of the side planking.

 

                        

 

                        

 

The diagonal bracing appears to be used to support the aft edge of the bottom planking where it meets the transom, but from the above photos it is also difficult to see how the diagonals were installed.  There are some pieces labeled ‘temp’ in the first of the above photos, located where the diagonal would be expected to be, and in the second photo it appears that the diagonal braces are let into the stern timbers by means of notches in those timbers.  The diagonals in this photo appear to be new wood when compared to the other wood in the photo.

 

The following photo appears to show some of the stern timbers being replaced.  The two innermost timbers appear to be original, and the outermost timber on the starboard side appears to be original as well (there doesn’t appear to be any outer timber on the port side).

 

                        

 

From the following photo, it appears that the reconstruction tied the stern timbers into existing deck beams, which probably would not have been possible in the original construction.

 

                        

 

The following photo shows ribbands installed across the stern timbers, and illustrates the slight curve of the transom. 

 

                        

 

This curve is also illustrated in the stern view of the profile plan shown in the lines plan.

 

                        

 

The following photos show the first new transom plank being installed.  The curve of the transom can be seen in this photo.

 

                        

 

                        

The next photo shows the transom planking completed, and a new chine plank being installed.  The outermost port stern timber has been installed, but it’s hard to see what supports it. – it appears to be floating and not attached to the strongback. 

 

                        

 

And another view of the transom, this time showing the outermost starboard stern timber, also illustrates how these outermost timbers don’t meet the strongback.

 

                        

 

The last photo of the transom shows a bottom plank being installed, and also appears to show how the bottom planks run flush with the lower part of the transom.

 

                        

 

So I’m still struggling with the following questions:

 

1.    How should the stern timbers be drawn?  Since they are diagonal, the length shown in the top view does not represent the actual length of the timbers.

2.    Should the outer edge of the stern timbers be shaped to follow the slight curve of the transom?

3.    How are the outermost stern timbers secured in place?

4.    Should the diagonal bracing be installed by notching the stern timbers to accommodate them, or should they lay on the stern timbers?

5.    Would it make sense to install the aft deck beams before the stern timbers?  This might give a ‘landing place’ for the outer stern timbers, but it would also require the deck clamp to be installed first.

 

I’m trying to build Kathryn as she was originally built, so following what is shown in the reconstruction photos will not always be appropriate.   I would greatly appreciate any help in solving some of these questions.

 

Thanks everyone!

 

 

[thibaultron]

I think the "temp" label refers to the bolt pointed to by the arrow. The outer timbers may be free floating, and serve only to tie the side and transom planking together at the corner.

[Sailor1234567890]

That bolt pointed to looks like it would rust away in a heartbeat. I suspect Ron's right. It's put in temporarily until they can get some good silicon bronze or other more suitable material. In a vessel that size, perhaps galvanized? It is most certainly pointing to that hardware store grade bolt as being something to replace with quality material at a later date. 

[Mahuna]

Ron and Sailor - I think you're right in the 'temp' pointing to a bolt - thanks. 

 

Ron - I don't see how the outside timbers could be 'free-floating' - in the photos of the first transom plank being installed they appear to be solidly in place before the plank can be attached to them.

[EdT]

Well here goes, Frank.  Not sure I understood the first question correctly, but maybe this will help.

 

How should the stern timbers be drawn?  Since they are diagonal, the length shown in the top view does not represent the actual length of the timbers.

 

I assume the question is how to loft the true shape of the stern timbers.

 

Since the stern timbers are in vertical planes parallel to the keel, their true shape will be shown in the side elevation view.  However, only the center timbers are shown on the sectional, elevation view.  The timbers on either side will be shorter.  At the forward end, the timbers all terminate at the strongback that is perpendicular to the keel so the forward ends of the timbers are defined (and are the same) on the existing elevation view.  To determine the length of each timber project its aft end from the plan view down (or up) to the elevation view.  If you wish to loft the bevels you will need to project both the inboard and outboard faces of the timber down to the elevation view.  If you plan to bevel the timbers after installing (recommended in this case), use the inboard, larger face of the timber when projecting the end from the plan to the elevation view.  Assuming the upward curve of the transom is constant, join the lower point of the timber at the strongback to the end of the timber with a curve of that shape.  Draw in the top line of the timber using the molded dimensions of the center timbers.  If you are not sure about the shape of the upward curve, leave material for later beveling by eye.

 

 

2.    Should the outer edge of the stern timbers be shaped to follow the slight curve of the transom?

 

I would say yes, but perhaps by eye after assembly as recommended above.

 

3.    How are the outermost stern timbers secured in place?

 

They seem to be floating in space in the photos, perhaps because rot was cut off?  I would be inclined to found them to the strongback, which is a sort of wing transom.  These may need to be thicker than the other timbers so the can be shaped to the outer hull.

 

4.    Should the diagonal bracing be installed by notching the stern timbers to accommodate them, or should they lay on the stern timbers?

 

In the photos they appear to be using short cuts of wood between the timbers that a fastened to "shelf" pieces screwed to the timbers.  I believe notching the timbers to take the diagonals would be stronger.

 

5.    Would it make sense to install the aft deck beams before the stern timbers?  This might give a ‘landing place’ for the outer stern timbers, but it would also require the deck clamp to be installed first.

 

I have no opinion on this, but would probably want the structure to be self-supporting first.

 

Cheers,

 

Ed

[Mahuna]

Thanks, Ed.  I appreciate the guidance.  Now all I need to do is execute it!

 

I'm going to try building the entire structure (including the strong back) before attaching it to the vessel.  I think this may make it easier to do the fitting and shaping.  I could leave shaping of the outermost timbers until the assembly is installed onto the keelson.

[Mahuna]

Part 12 – Knightheads

 

It has been almost 2 weeks since my last post.  The delay comes from two things: a lot of non-modeling activities and responsibilities; and a lot of time spent trying to work through the correct process for the next elements of the Kathryn build.

 

Part 11 dealt with the complexity of the stern timbering and my questions on how to proceed.  In addition to these questions, I was also a little perplexed about installing the knightheads – but these are simpler than the stern timbers, so I decided to tackle them first.

 

Before working on the knightheads or the stern timbers, I thought it would be a good idea to mark off the location of the deck clamps on each side of the model.  The clamps are 5-1/2” x 2-3/4”.  The drawings show the height of the bottom of the deck, so I measured down from this value for each frame and used the tools in the following photo to mark the lower edge of the deck clamp on each frame.

 

                        

 

The height gauge could be set to the nearest 1/1000, so I calculated the measurement to this value and used a straightedge to mark the bottom of the clamp on each frame, as in the following photo.

 

                        

 

I set the height gauge to the appropriate value, laid the small straightedge against the lower edge of the gauge, and marked the line using a .003 pencil.

 

In marking the clamp positions, it became apparent that the wires holding the temporary ribbands in place would interfere with the installation of the clamps.  Since ribbands needed to stay in place until after the clamps were installed, it was necessary to move the ribbands to a better position.  The solution was to install a full ribband lower down the hull from the original ribband and then, after removing the original ribband, to install a partial ribband on the forward frames – lower than the clamps, but high enough to achieve the correct fairing of the hull.

 

                        

 

The knightheads are 22” x 4”, and are tapered to fit against the inner stem (apron) at an angle that supports the side planks.  In reviewing the drawings of Kathryn, I didn’t see any other point of attachment for the knightheads, and I felt that this tapered edge wouldn’t provide much strength to the knightheads.  This question and the associated confusion on my part caused a delay of several days, so I finally asked a couple of friends who are very knowledgeable about skipjacks and Chesapeake workboats in general.  The answer was very instructive, and I thought I’d share the entire answer:

 

“by the time they were edge nailed to the apron, sandwiched between the sheer clamp and side planking, and notched into the front end of the covering board (sheer-plank) and king plank, and supported outboard by the log-rail and by the breast-hook(s) between them (often one under the sprit and/or one on top of the sprit.) they became a pretty formidable structure.

 

i learned that their function was to support the bowsprit against sideways forces in the same way as the partners support the mast.  also the extra thickness, and the nails therein, helped reinforce the bow planking against getting stove in and sprung out in the days of thick ice on the bay, and the hawse hole reinforcement was helpful too.

 

back in the old days (1995) when i helped rebuild thomas clyde they removed the knight heads. they then made a new apron and all new planking but no new knight heads - i was appalled and dismayed but them good-old-boys told me they din't really do nothin' and they rotted out fast.  as i was new on the job and my only expertise came from reading howard chapelle the night before, i backed off and the boat is still floating.  [doesn't look as nice though.  and we really did have any bad ice since then - and if we had they would have stayed in port anyway.]”

 

So with my questions answered I made the knightheads.  After the appropriate plank was milled it needed to be tapered to match the lay of the planks (based on the position of the ribbands).  The disk sander was set at the maximum angle and the taper was sanded into the knighthead plank.

 

                        

 

This initial shaping didn’t provide enough angle, so the final tapering was done using a fine stump cutter on a rotary tool.

 

                        

 

The following photo shows the starboard knighthead ready for installation.

 

                        

 

I tired several approaches to clamping the knightheads for gluing to the inner stem (apron), but the angle made this difficult.  I settled for using a couple of spots of medium viscosity CA glue in addition to the PVA glue.  After holding the knighthead in place for about a minute, the CA then acted as a ‘clamp’ until the PVA finished curing.

 

                        

 

The following photos show the knightheads installed.

 

                        

 

                        

 

In order to provide some additional strength on the model, 1/32” brass rod was used as structural bolts through the knightheads and into the inner stem, and was epoxied in place.

 

                        

 

Some progress has also been made on the stern timbers, and will be covered in the next post.

 

Thanks everyone!

 

[Omega1234]

Hi Frank

 

Kathryn's definitely coming along very nicely.  At the rate you're going, it probably won't be long before you start planking the hull.

 

All the best!

 

Cheers

 

Patrick

[albert]

Very nice work Frank.

[popeye the sailor]

gives a good anchor point for the planking at the bow........very nice work  

[Mahuna]

10 hours ago, Omega1234 said:

Hi Frank

 

Kathryn's definitely coming along very nicely.  At the rate you're going, it probably won't be long before you start planking the hull.

 

All the best!

 

Cheers

 

Patrick

Thanks, Patrick.  Lots of work still ahead.

 

3 hours ago, albert said:

Very nice work Frank.

Thanks, Albert.

 

1 hour ago, popeye the sailor said:

gives a good anchor point for the planking at the bow........very nice work  

Thanks, Popeye.  To me, the knightheads are real important for the planking to sit correctly.

[HIPEXEC]

Moving along nicely

[kees de mol]

I'm impressed by both your workspace and tools but for the most by your shipbuilding. Great job

[Mahuna]

18 hours ago, kees de mol said:

I'm impressed by both your workspace and tools but for the most by your shipbuilding. Great job

Thanks, Kees.  I'm very happy with my shop and tools - and for my very understanding wife!

 

I visited your 'museum' and enjoyed it very much.

[Mahuna]

Part 13 – Stern Timbers

 

Well, I finally found the time (and the courage) to work on the stern timbers.  After several attempts at drafting the timbers, I decided to use a simpler approach.  I would use the profile of the middle timber as a guide, and would alter the length of the various timbers as I assembled the stern.

 

The first step was to correct an error I had made in cutting the end of the keelson, which I had left perpendicular.  The strongback is mounted against the keelson end, and sits at the same angle as the end of the keel.  A small wedge was made and installed to give the keelson the appropriate angle.

 

The drawings of the stern timbers and the strongback were glued to the appropriate stock and then cut out on the scroll saw.

 

                        

 

A mounting slot was cut into the forward edge of the strongback to provide a more secure mounting position when joined to the end of the keelson.

 

                        

 

A drawing of the timber arrangement was then glued to the strongback.  This drawing showed the positions of each of the stern timbers.

 

                        

 

Slots for each of the stern timbers were then milled in the strongback.

 

                        

 

These slots were tight enough to allow the temporary positioning of each of the stern timbers.  In the following photo these timbers are held in place by friction, with no gluing involved.

 

                        

 

The length of each timber was then determined by matching this configuration against the drawing of the stern timbers.

 

                        

 

The profile drawing of the stern timbers was then used to ensure that cutting down the length of the stern timber resulted in the correct angle for the end of the timber.

 

                        

 

The stern assembly was then glued together, using small braces to ensure the correct parallel alignment of the stern timbers.

 

This assembly was then marked for the diagonal braces that were to be installed.

 

                        

 

Since these braces are let into the stern timbers and sit flush against the edge of those timbers, stop cuts were made in each timber to guide subsequent cutting.

 

                        

 

The slots were cut down to the final depth using a small chisel and a hobby knife.  (Apologies for the out-of-focus photos)

 

                        

 

The outer timbers were made of thicker stock than the interior timbers since they need to be shaped to allow hull planking to properly lie against them.  The initial shape was determined by laying a transparent template over them.  This transparent template was made by printing the drawing on transparency paper, and allowed proper alignment by showing the individual timbers.

 

                        

 

The outside edge of the end timbers was roughly shaped using a fine stump cutter.  Final shaping, or fairing, will be done when the planking is laid. 

 

                     

 

The following photo shows the partially finished stern assembly with the transparent template.

 

                        

 

Clamping the stern assembly to the keelson for gluing proved difficult, so two temporary ribbands were used to provide support.  These ribbands were held in the proper position at the stern by aligning two heavy squares with the outer edge of the drawing on the construction board.  This forced the ribbands to the correct shape and provided a relatively solid way to hold the stern assembly in place during the gluing process.  (I was later informed that the skipjack builders would often use scaffolding to hold assemblies in place during the building - similar to my use of these ribbands)

 

                        

 

                        

 

The stern timbers are permanently in place, but are rather fragile.  They can be further secured by the installation of the deck clamps, which will be the topic of the next post.

 

                        

 

 

 

[Mahuna]

Part 14 – Deck Clamp

 

Ok, so 2 updates in the same day - this will bring us to the current state of the build.

 

Kathryn’s deck clamp runs the entire length of the ship, and is made from pine.  A reinforcing piece made of oak is installed over the forward part of the clamp.  The main clamp was cut into two pieces, joined at frame 12.  This will allow the reinforcing piece to sit over the joint when it’s installed later in the build.

 

Before installing the clamp, it was necessary to install the forward-most frame, which is let into the stem knee rather than the keelson.

 

                        

 

                        

 

This frame will provide additional support to the planks in the bow area.

 

The deck clamp can provide some needed structural support to the stern assembly if it is attached to the outermost stern timbers.  A notch was cut into the end of the deck clamp to match the shape of those stern timbers, and the clamp was then glued to the stern timber as part of the installation.

 

                        

 

Since the deck clamp will keep the frames aligned until the ceiling and outer planks are installed, it was necessary to glue and clamp the deck clamp to every one of the hull’s frames.   This made for a very tight setup.

 

                        

 

The finished deck clamps have provided good overall strength to the frames and the stern pieces, and the final shape of the hull can now be seen.

 

                        

 

                        

 

As can be seen in these last two photos, some of the ceiling planks have been started.  This will be the topic for the next post.

 

Thanks everyone! 

[GuntherMT]

Great work as always.  Love seeing your updates.

[Mahuna]

1 hour ago, GuntherMT said:

Great work as always.  Love seeing your updates.

Thanks Brian.  It's been slow going due to lots of other things happening.

[GuntherMT]

8 minutes ago, Mahuna said:

Thanks Brian.  It's been slow going due to lots of other things happening.

 

I know the feeling.

[druxey]

Looking lovely, Frank. Great job with those raking stern timbers. All those clamps made me think of a row of exotic budgerigars perched on a wire!

[Mahuna]

1 hour ago, druxey said:

Looking lovely, Frank. Great job with those raking stern timbers. All those clamps made me think of a row of exotic budgerigars perched on a wire!

Thanks Druxey.  I always seem to be learning something new from your posts - in all my years of bird carving and learning about birds, I never heard the name 'budgerigars' used for parakeets!

[druxey]

I say tomahto, you say tomayto!

[Omega1234]

Hi Frank

 

She's really coming along beautifully!  There's no doubting the shapeliness of the sharpie's hull design, especially now that the deck clamps have been installed.  

 

Yep...Lovely...Shapely...yet Precise.

 

Cheers

 

Patrick

[Jack12477]

11 hours ago, Mahuna said:

Thanks Druxey.  I always seem to be learning something new from your posts - in all my years of bird carving and learning about birds, I never heard the name 'budgerigars' used for parakeets!

Ah yes, the little "Budgies or Budgees" - had 3 or 4 of them when my kids were young.  

 

Enjoying your build immensely, Frank.  Nice work.

[Mahuna]

10 hours ago, Omega1234 said:

Hi Frank

 

She's really coming along beautifully!  There's no doubting the shapeliness of the sharpie's hull design, especially now that the deck clamps have been installed.  

 

Yep...Lovely...Shapely...yet Precise.

 

Cheers

 

Patrick

Thanks Patrick.  Unfortunately Kathryn is coming along much slower than I had planned - other priorities keep showing up.

 

10 hours ago, Jack12477 said:

Ah yes, the little "Budgies or Budgees" - had 3 or 4 of them when my kids were young.  

 

Enjoying your build immensely, Frank.  Nice work.

Thanks Jack - glad you like it.