24' exploration gaff-rigged ketch by vaddoc - FINISHED -Scale 1:12, a Tad Roberts design

[vaddoc]

While the glue is setting on the last two frames I started working on the transom. I still have not found a solution how to hold it in place. I think some kind of jig will be needed.  

In Tad's plans (scaled down) the Transom is made of 1 mm plywood with a 3 mm frame. In my plans the transom is solid 4 mm. I will first bevel the transom and then maybe leave it as it is or maybe  sand 1 mm off, cut the central part and glue plywood on the back.

 

I do not have 4 mm thick sheet so I laminated 2 mm ones. The sheets are not perfectly flat so lots of clamps were needed!

 

 

I did my first mistake and beveled the other way around the edge of the transom where it reaches the building line. No harm done though as I will need to built some kind of jig either way.

I d rather do as much of the bevelling before assembly so I left only two narrow strips to reach the building line. Some of the bevelling could be done with the disc sander and the result was fantastic

 

 

 

 

[vaddoc]

I also cut the plywood for the bottom and lower chine

 

[captainbob]

Coming along nicely.  I like your creativity in figuring out how to do things.

 

Bob

[vaddoc]

Your support is much appreciated Bob! I admit I should have read a book or two about modelling but it's more fun to built than read. 

[vaddoc]

Ok, today I tackled the dreaded stem lamination. I took no risks this time.

 

The strips have retained their shape well.

 

 

I used super glue to attach a piece of supermarket plastic bag on the jig.

 

 

And measured the resin and hardener very carefully! I added talk powder to peanut butter consistency.

 

 

Fingers crossed this time!

 

[vaddoc]

Now something I need to share with you all. I was not entirely happy with the Transom so I decided to start over. The two sheets were pretty much flat but after the PVA glue went on they warped. I have never come across this, I guess the water in the glue caused uneven swelling in the wood. I suspect my wood is very dry.

 

 

 

[vaddoc]

At last all the frames are ready! The notches seem to align reasonably well although I suspect they are not deep enough. There will be two plywood planks in the bottom and lower chine, 1 mm thick and 4 pear planks 1.5 mm thick for the middle and upper chine as well as an inner and outer clamp. This is a strange boat, the lower half of planking will probably need to be constructed with epoxy filleting and the upper half clinker built with rivets. 

 

 

[Jim Lad]

That ply has really warped, mate - I've never seen that happen.

 

In spite of surreal ply, she's coming on beautifully!

 

John

[vaddoc]

Today I removed the stem from the jig. I t looks very good, no spring back at all and no delamination.

 

 

I cleaned as much of the epoxy as i could from one side of the face before it cured, but the other was inaccessible. It needs to be sanded off while keeping everything square. This will be challenging.

 

[michael mott]

 

"This will be challenging."

This is the unofficial motto of scratch building

 

Congratulations on the work so far. Regarding the warped wood, Might I humbly suggest wetting the whole piece of wood by dropping it into a tub of water and washing off  the present glue. wipe it dry and let it normalize or go flat again, it will either flatten by itself or might need a book or two to act as a flattening aid.

 

When it is either flat or flexible again because of the replaced moisture, before it dries out completely re-glue and re-clamp and leave until completely dry.

 

Michael

[vaddoc]

This is excellent advise Michael, I wish I had this knowledge at that time! I use aliphatic PVA glue which is not water proof but as I put a lot of glue for laminating, the wood might be unusable. I will soak it though to see how it will respond.

For future reference, if wide pieces need to be glued, do you think these should be soaked in water first to saturate evenly and prevent warping?

[vaddoc]

I had very little free time today but I just had to finish the stem. I must say, it took very little time and the job was completed entirely using the homemade disk sander. I used 6 mm strips but in the plans the stem width is 5.3 mm. After sanding the epoxy off the width was 5.8 mm.

 

 

Although I was only 0.25 mm off on either side I decided to sand a bit more forgetting the old saying "Better is the enemy of good". The result was that I sanded a bit more on the side that meets the No 1 frame reaching 4.9 mm width. No harm done though as although slightly thinner it is symmetrical. The junction of the shaded and non-shaded areas is where the planks join the false stem. Of course due to the tolerances it can only be used as a rough guide. In any case I now have a strong smooth false stem!

 

 

 

 

Next tasks:

1. Transom

2. Jig and setting up of frames

3. Laminate Apron

 

 

[michael mott]

Vaddoc, I would do a test with the particular type of wood that you will be using. The basic premise its to balance the moisture so when you go to glue the piece simply coat one side with a sponge to wet it apply the glue to the other and then clamp together.

 

Michael

[vaddoc]

Michael, I will definitely try this before I glue any large pieces. The PVA glue I use is old and has thickened a lot but the warping proves that moisture needs to be balanced.

I did some more work on the Transom (this time laminated with epoxy) and also built a cradle to keep it in place. I am sure the angle will be fine, the difficult will be ensuring it is perfectly square to the midline.

 

 

 

 

 

As for the frames, I cut 90' triangle shapes. I used the wood from a garden support I bought from Poundland, it is actually very dense and strong and sands very nicely. I intend to make sure the frames are vertical and in position and then glue the frames to the shapes and the shapes to the floor. When the Apron and the outer clamp are inserted the boat should be pretty rigid. 

 

 

[Yambo]

Hi Vaddoc, just caught your build log for this nice looking boat! I have the same plans up in my 'to do' cupboard but other things keep getting in the way. I might get around to it sometime!

 

Interesting to see how you're approaching the build. Ages ago, or so it seems now, I found and put away some mahogany that I thought would be useful for the keel and I got my son, an aircraft sheet metal worker to make the centreboard out of a piece of aluminium. These bits are sitting around somewhere - but then so is a lot of stuff    .

 

Anyway, keep enjoying the build; I'll keep watching.  

[vaddoc]

NIce to have you along Yambo, I know what you mean, I hope things will settle so you can join the frustration of trying to put this thing together!

I used mahogany extensively in my previous boat and although I liked the colour I will probably not consider it in the future. It is very strong but sanding and shaping it is difficult. I used mahogany for the deck and then wanted to give it a shiny finish. It is so porous though that It took a dozen coats (or more) of tang oil, shellac, varnish and wax to get some kind of shine. But it is beautiful wood indeed!

Today was a bad day. I test fitted the stem and the station 1 frame only to discover that the stem is short. Instead of sanding the stem to the building line I sanded it to the sheer! 

 

 

 

But of course that was not the only problem. As I was looking at the above picture I realised that I sanded the wrong side of the line at the end joining the frame. The notch should look up to receive the apron !

 

A pint of beer later I started the process of laminating the stem-for the third time now! The walnut strips sit in the jig now waiting to cool down till tomorrow.

 

 

Stems were invented by the Devil himself.

Edited January 15, 2015 by vaddoc

[Omega1234]

Hi Vaddoc

 

Not to worry....sometimes things just happen for a reason. Maybe it was your body saying that you needed that pint of beer!

 

Nonethess, you'll get it sorted in no time and then you'll be off and running once the new stem is laminated and dried.

 

All the best!

 

Patrick

[vaddoc]

Thanks Patrick, indeed the new stem is now drying! I've ended up using this jig more than my favourite disc sander.

 

 

I printed out the pattern to position the frames and i realised that the nice thick piece of MDF i had saved was warped. I used the last piece of the old drafting table and I could not resist arranging the frames and transom. Looks so much better than the first attempt!

 

 

 

Of course I had to add a strip to check the bevelling for the apron. It feels pretty near.

 

 

And of course check the bevelling randomly on the port side...

 

 

...and the starboard side. I am a happy man! 

 

[Omega1234]

Hi Vaddock

 

Nice job on the bevelling! Your planking will definitely run nice and sweetly, without any problems.

 

Cheers

 

Patrick

[michael mott]

 

I started the process of laminating the stem-for the third time now!

Good morning Vaddoc, welcome to the club, fees are generally pretty low, looks like you passed the initiation test well enough.

 

The lines of the planking look like you will have some sweet curves.

 

Michael

[Jim Lad]

Now the real fun begins!

 

John

[vaddoc]

I think that the curves will be fair, however there are many challenges. In my CAD plans the plank overlap is 2 mm which is enough for some kind of rivet. It is too easy though for the planks to be gaping or the overlap to be inadequate. The edges will need also bevelling where they meet. I have never done these before, i am really curious to see how all will come together!

 

Today I rechecked all the frames against the patterns and marked the midlines. I discovered that the frame at station 7 was off by about 2 mm. This was the frame that looked a bit loose on the test fitting. Only solution to make it again.

 

Most importantly, I finished the stem! 

 

 

 

I am not sure regarding the centerboard and the case, Tad does not give precise dimensions and in the plans the centerboard and case have various shapes through the pages.

 

 

 

This is a problem as the case also supports 2 thwarts and the mizen. This will take some serious headscratching. Frames 4 and 5 will need to be cut to fit the centerboard case and also notched to accept the case logs which are 2 long timbers connecting the 2 frames and supporting the c/b case.

 

 

I decided to take a break and to change focus for a while by working on the planks. They will be 1.5 mm thick cut from a sheet of pear wood. Each has a different shape which can be very far from straight. I wonder where they would get planks that wide to built the full scale boat!

 

 

I secured two sheets so that the planks for both sides could be cut at the same time. Due to the shape and the length of the planks the disc sander was not useful so most of the sanding had to be done by hand. The first 2 planks are ready and look good

 

 

Next job I think is to sand smooth the frames and Transom, better to do it now rather than after the hull is assembled. I liked very much Ed's beewax finish on the Young American build. The other option is sanding sealer and varnish but the wax looks easier. What is the crew's opinion on this?

[vaddoc]

I have not posted for some time but I have not been idle. I realised that although the frames, stem, planks and bevels were dealt with, I still had no idea of how to arrange the thwarts or the floor. Maybe this is something easy for an experienced builder but it was a cause of concern for me. Tad just writes “sit riser midships tapered at ends”.  

 

Searching the Internet I came across a group that actually built the boat and travelled to Alaska. Their boat is beautiful, probably the same one on Tad’s website. The group had kept a log of the build but it was unavailable, they did however post a number of photographs from the built and also photos from the boat sailing. Unfortunately, most are very low resolution. These photos led to all sorts of new problems that needed a solution. I will expand on some of these as it might help future modellers.

First of all, the group did not laminate the stem but built it with solid wood. That was a punch in the stomach! Still, I like my stem better.

 

 

 

 

Looking at the pictures, I realised that the floorboards, which are very thick, cannot follow the curvature of the keel and the frames but need to be straight. This makes sense as really it helps stepping on a flat surface. So, the part of the frames that supports the apron and the plywood planks cannot be bevelled but the heights need to be adjusted to provide support for a straight floor. In their boat also, fore of frame number one the floor forms a step and is at a higher level.

 

 

 

 

 

 

Their boat does not use sit risers or brackets but knees to support the benches.

 

 

 

Their boat also has a small deck with 2 hatches. Strangely, this is formed by the curved planks of the benches on either side of the boat extending all the way to the stem. I spent a week on CAD trying to figure out how they did it and failed. The problem is that the benches are straight and generally parallel to the water line at the height of the centreboard cap, which supports 2 of the 3 thwarts. The benches extend aft to the transom and form the thwart. Their deck though is at such height that it is not possible to have the deck, the benches and the centreboard cap at the same level considering the generous profile view curve of the sheer. Absolutely impossible!

 

 

 

 

 

 

 

 

 

 

 

 

The following photos show the arrangement of the benches and thwarts. The 2 red lines show the level of the benches and deck at the upper edge of the centerboard case and the angle the benches should have to also form the deck, which of course is impossible. I am at a loss how they did it.

 

 

 

 

 

Also, the height of the thwarts is important as it should be at such distance from the floor to allow comfortable bending of the knees when sitting, but also at such height relative to the sheer as to allow for rowing and the lever oars need. This though cannot be independent of the centerboard case which supports the thwarts and this in turn depends on the shape and size of the centerboard. Pure frustration.

Edited January 25, 2015 by vaddoc

[Yambo]

Well, that's the thing about boats Vaddoc, both full size and scale - the plans give you the designers ideas and dimensions for a basic boat but don't restrict you from doing your own thing during a build. 

 

You're not building Tad Roberts' boat, you're building your own from his plans, just as that team built their own depending on what they needed to use it for - extra stowage space for example.

 

When I was building my CLC Skerry I looked at lots of other boat builders' ideas but ended up building it as per the plans, both the full size one and the scale model I made.  It works, but it could be different. Knees or risers for the thwarts? Risers will be easier but it's your choice.  

[captainbob]

How it was done, what a great find. 

 

Bob

[vaddoc]

Yambo this is very interesting, I had not previously appreciated the degree of freedom one has when building from plans. But to deviate from the plans certainly takes a lot of skill and experience. I guess you built the model before the actual boat to better understand the building process, I had read that this is a good idea but only now I appreciate this. If I was building the full scale boat I would have gone bankrupt by now!

I was very lucky to find these photos Bob, they really are very helpful and show the beauty of boatbuilding. 

 

I finished the No7 frame and also finished all the planks. The curved segments were sanded with the disc sander within seconds but the concave ones were tricky. The improvised router table worked well.

 

 

 

Following Yambo's advise I decided on the layout of the interior. Knees, a small deck with hatches, almost identical but not quite to the boat in the internet photos. The floor, benches and deck are half ready.

 

 

 

 

I also was not happy with my transom. It made it solid instead of framed plywood but I like the original design better so I redid it and it looks good! I will cut the excess plywood ofter planking. In the last picture the Transom is secured to the jig.

 

 

 

 

 

Has anyone tried the beeswax approach for finishing?

[vaddoc]

Progress has been slow as the built is becoming more complex. I have decided to add all the knees and the beams that support the side benches, thwarts and deck to the frames before assembling the hull. In the full size boat this would be done after planking but I think it would be very difficult. I will also need to make and add the centerboard case and all the supports for the floor. This is massive work and it is a bit strange, months of work and nothing to show but a glimpse of the hull lines when test fitting the frames! I think this is a case when you need to treat every small component as a model of it self.

Of course all these will need to be finished prior to installing. I am sold on the Renaissance wax which excited expectations in my testing.

 

Back to the computer then. The next photo shows the template for frame No 7.

 

 

The knees will be made full lap which is a bit of a challenge as the pieces are becoming too small.

 

 

All done. The paper template is glued to the back of the frame

 

 

However, when I add the knees and floor supports I will not use the paper template. I have made a simple jig so that all knees will be positioned at the same height without tolerances

 

 

I realised that I need a drill press, I am surprised how widely inaccurate hand drilling is, at least for me. I also keep bending the drills. I got clearance from the wife and I am thinking of getting the Proxxon 28128 TBM 220. Any thoughts on this?

 

 

[vaddoc]

The work is progressing well and many components are ready to be installed. I still need to design on CAD the deck arrangement with the mast partner and beams, the floor arrangement and aft thwart at the transom.

 

The planks for the benches are ready to be cut, I am thinking of improvising some short of sanding jig which will have the shape of the benches to assist in sanding the inside part of the planks.

 

 

 

This is an overview of all the components already prepared, not including the planks

 

 

 

 

I also made the centerboard, it should be made of steel but I think a common alternative is a laminate of wood core sandwiched by plywood and fiberglassed over. This is what I did minus the fiberglass. It still needs some sanding and painting. It came out super stiff.

 

 

 

 

 

I also did some work on the centerboard case which is coming out really nice.

 

 

 

I try to make sure everything is sanded before assembly and that excess glue is cleaned immediately. All joints so far are very clean.

 

 

 

I also glued the knees for the frames 1 & 8 using the jig and things look reasonably aligned. It is not a really solid process but it works so I am sticking to it for now. Everything is sanded before assembly and since I will be using Renaissance wax no other preparation is needed.

 

 

 

 

 

I have ordered the Proxxon drill press which will be I think extremely useful. If I had it earlier, assembly would be much easier and accurate. Lesson learned.

 

[Omega1234]

Hi Vaddoc

 

Looks like you're progressing really well with fabrication of the centreboard, frames, etc. It won't be long now before you'll be able to start assembly and enjoy the rewards of your hard work.

 

Cheers

 

Patrick's

[vaddoc]

Your support is much appreciated Patrick, especially as time is running out...there is a little one due in 6 weeks and undoubtedly work will slow down to a halt.

 

I will present briefly the process of glueing the knees. First everything is sanded to 400 grit.The paper pattern is used only for the lateral adjustment as the height will be set by the jig.

 

 

I could not resist bevelling the ends of the knees although I think they might not be visible

 

 

The contact areas are marked on both sides to apply glue appropriately. The green clamps are used in gardening, I find them very useful and costed me £1 for a pack of 20! Excess glue is carefully cleaned with water.

 

 

 

 

 

The lap joints in the frames came out nice, the frame is only sanded, when the wax is applied it will show much less I think

 

 

All knees and some of the beams supporting the thwarts are ready. I have some 1 mm walnut dowel which I am thinking of using as nails or I might save it for the planking and use toothpicks instead.

 

 

Before I do any more work I really need the drill press, until it arrives I will work on the floor and deck arrangements.