21' Fisherman's Launch by vaddoc - Scale 1:10 - Plans from Howard Chapelle's "Boatbuilding"

[vaddoc]

A lot of progress today, things at last seem to fall into place. It is bitterly cold and England seem to be boiling with coronavirus. I had requested a week's annual leave and since we cannot leave the house, it is an opportunity to work on the boat.

 

I attached small pieces to the top surface of the keel to keep the frames in place. These are glued and screwed in place except three that will need to be removed later so that floors can be attached. It is not an elegant solution but will be invisible and in this boat I have accepted that I will cut some corners to speed up the construction. I then brought everything together and checked for fairness. I had to chisel away some wood from frame No1 but happily, it seems that the hull is now fair. Planking will tell: the planks will be 2 mm stiff beech which will not tolerate any waviness in the hull. 

 

Then, I glued the stem and stern timbers. I used initially epoxy, thickened with plaster. The reason is that when I made the pieces, my disc sander was very slightly out of vertical alignment so I needed something with gap filling capabilities. It actually went very well and the keel is very close to the plans. 

In the next photo, the two boats are side by side. They are so different, I am very curious how planking will go.

After a couple of hours, the epoxy had hardened. However, it is not enough-it needs further strengthening.

I inserted 1 mm screws and secured the knee to the keel and to the stem-4 screws each. I took pictures which unfortunately were lost. I then inserted 2 more screws to secure the stem to the keel. The bow is now super strong. The holes will be filled later on before painting.

Then I screwed the stern assembly to the keel. I had to remove a block to insert the screws underneath.

I had huge troubles though inserting screws to the other end as I could not use the drill press. Finally I manage to get one screw in place-It should be enough.

 

I then started to glue cross members to the frames. These will later be also screwed in place and more pieces will be glued length wise to stiffen up the structure.

Next, I will finish the keel, that is cut the rest of the rabet and remove the paper pattern and sand it smooth.

Now, on another note, I cannot find the transom. I am absolutely certain I had cut it but I simply cannot find it. I ll need to make it again and then it will be time to bring everything together. 

 

Best wishes

Vaddoc

[Wintergreen]

15 hours ago, vaddoc said:

I ll need to make it again

And a couple of minutes after that, the already cut one will reappear 😄 

Nice progress Vaddoc. 

Where do you source such tiny screws?

[vaddoc]

22 minutes ago, Wintergreen said:

Where do you source such tiny screws?

Thanks Hakan

I buy these screws by the thousand from our Chinese friends at Aliexpress. They come in various lengths and I find them very useful.

They need a pilot hole of 0.7 or 0.8 mm. A good screwdriver is also needed, AAA or AA.

The AAA shaft has the same diameter as the head of the screw if it needs to be deeply countersunk.

Look for "self tapping Philips head screw" but get the stainless steel ones (non-magnetic), plain steel have their heads round off very easily.

 

Having said that, the last "stainless steel" I got seem to me to be just plain steel, they are rubbish all 2000 of them...

 

Regads

Vaddoc

[wefalck]

Interesting project ...

 

Normally, stainless is softer than other types of steel used for scews, as the alloying elements interfere with the hardening process.

[vaddoc]

5 minutes ago, wefalck said:

Normally, stainless is softer than other types of steel used for scews, as the alloying elements interfere with the hardening process.

Thanks Wefalck

The normal magnetic steel variant is made of some kind of soft mild steel and the head gets destroyed very easily. The stainless variant is just a touch magnetic and much more resilient.

 

[vaddoc]

I hit a bit of a milestone today, the backbone of the boat is ready!

 

I first finished the cross members in all frames and removed the paper templates. Then, I continued work cutting the rabet. At the bow it was relatively straight forward. At the stern however, things were more complex. The problem is that the keel is not horizontal but slopes downward towards the stern. I have no idea how the planks will be arranged and as a result I am not sure how to hollow the deadwood. I installed all the aft frames and eyeballed things, I think there will be more wood to remove but I don't think I am far off.

 

I ve been using the strop on my chisels every few cuts and now they are extremely sharp, even a casual contact with the fingers will draw blood. This allowed however for very precise cutting. Next I removed the paper patterns from the keel and sanded to 240 grit. 

Then I assembled everything and checked for fairness. It looks ok, maybe a tiny amount may need to be taken off frame 1 at places but really it is not far off.

Next, I need to make (again, could not find it) the transom and secure it to the hull. I will need to add some side horn timbers and also to make some kind of jig to hold the transom in place.

 

A last photo, aren't boats beautiful...

[BobG]

Beautiful work, vaddoc!

[Wintergreen]

9 hours ago, vaddoc said:

A last photo, aren't boats beautiful...

Yes, they are!

Good work there Vaddoc

[G.L.]

A straight keel. The rabbet looks very accurate. I like pictures like the last one. All the frames are nicely aligned in a flowing shape

[vaddoc]

Bob, Hakan, GL and to all that hit the like button-many thanks!

 

Now, I am struggling with this boat, it just refuses to come together nicely. The CAD plans are accurate and all the individual pieces seem quite accurate as well. However, something is wrong-this was made apparent today when I cut and installed the transom.

 

Today I had the whole day free and spend it going back and forth between the garage and the computer in the house. I did a bit more work on the transom plans,  then cut it from pear wood (took three expensive attempts) and also made a frame to strengthen it. Then I was just too frustrated to take pictures, I apologise!

 

Now, the problems started when I tried to install the transom to the keel. The height and angle of the transom is critical as it cannot be sanded or shimmed - it will show. Also, it needs to be dead centered and squared. A jig is needed to hold the transom securely into the proper position while the boat is planked. 

 

I made a jig from scrap plywood using a template directly from the CAD plans. Now, the transom was very accurately cut, the jig showed the proper height and angle. Well, the keel was sitting too high. 

 

So I removed all the frames. I made a couple of templates and checked the height of the keel at the position of the last two frames, with the keel resting only on the stem and transom jig - spot on. So some of the frames need more sanding to allow the keel to sit lower. Next photos show the transom jig and the pattern confirming all angles and heights are now correct.

I randomly chose frame 12 to check-indeed, it lifts the keel too high!

So I will need to check each frame on its own to make sure it fits without pushing the keel up and out of position. Then I hope that the boat will finally come together properly.

 

Now, I have also started doing a bit of thinking on the planking. It is probably going to be more complex than I thought as there will be quite a mismatch bellow the turn of the bilge between the bow and stern and probably stealers will be needed which is I think rather unusual for such a small boat.

 

Stay safe all

 

Regards

Vaddoc

[Wintergreen]

Ouch. I feel you and the frustration about the hidden error.

Good you found a way to spot it and further correct it.

Keep it up!

[vaddoc]

Dear friends

It is done!

Using the transom jig and the stem as guides, I checked all frames. Almost all had to be sanded to allow the keel to sit properly down at the proper level. Especially frame No 3 had a lot of material taken off. I cannot explain this as everything was cut quite accurately but in any case the frames are now in their proper position, the keel is straight and at the proper height and angle, the same with the trasnom.

 

Next jobs:

1. Connect all the frames with longitudinal wood pieces to increase rigidity

2. Epoxy the frames to the keel

3. Glue the frame to the transom, cut the bevels and secure the transom to the keel

4. Glue and shape the side horn timbers

5. Plank the boat!

 

Vaddoc

[Wintergreen]

Soo, what are you waiting for??? 😁

 

Sorry, just kidding. Well done on the frames part.

Keep it up!

[KeithAug]

Nice work, patience pay off in the long run.

[Bob Cleek]

I should check my copy of Chapelle's Boatbuilding to answer my own question, I suppose, but how was the transom shape presented in the book? If the actual shape of the face of the transom was what you used as a pattern, it should have come out fitting perfectly. If, on  the other hand, you used the projected shape of the transom edge from the station drawing, what would be there would have less height by just about the amount your frames were "pushing the keel up" because in the body plan it's shown as it would look at its angle of rake. This may explain the difficulties your encountered. Looking at a transom face that is perpendicular, the transom will appear taller than looking straight on at the same transom when it is raked slightly as it is when fastened to the sternpost. The actual surface shape of a transom has to be "developed" or "expanded" in the lofting. As I recall, there is a description of how to develop the various styles of transoms in Chapelle's Yacht Designing and Planning, but it's quite confusing. Alan Vaitses' Lofting explains developing transom shapes much more clearly. Here's another brief treatment of it online: https://www.duckworksmagazine.com/13/columns/austin/7/index.htm#.X_7Ws3ZKgdU 

 

Anyway, it was just a thought. You've cured the problem, but you may want to take a close look at your sheer at the transom now because if what I've described, a "short transom," was the issue, you'll encounter a similar measurement issue when it comes time to hang plank.

Edited January 13, 2021 by Bob Cleek

[vaddoc]

Many thanks to all for your likes and comments!

 

9 hours ago, Bob Cleek said:

The actual surface shape of a transom has to be "developed" or "expanded" in the lofting.

 

Indeed Bob, in all plans the transom might look vertical but essentially is the projection of the angled transom to the vertical plane. When I developed the plans on CAD, I did the opposite - that is I projected the transom as given in the plans to a surface in the appropriate angle. Then the sheer was faired and the hull developed and faired.

The problem was that the notches on the frames were not deep enough to accept the keel. This was evident as the transom was very accurately cut and positioned but the keel was hovering high up without touching the transom.

No idea how this happened as individually all pieces all seem to be very accurately cut but still refused to work together. So I am forgetting CAD accuracy-I ll just sand and shim things as needed until all curves flow nicely! But I checked the hull and it looks ok.

[Bob Cleek]

1 hour ago, vaddoc said:

The problem was that the notches on the frames were not deep enough to accept the keel. This was evident as the transom was very accurately cut and positioned but the keel was hovering high up without touching the transom.

No idea how this happened as individually all pieces all seem to be very accurately cut but still refused to work together. So I am forgetting CAD accuracy-I ll just sand and shim things as needed until all curves flow nicely! But I checked the hull and it looks ok.

 

Then that's it! I'm not "CAD literate," but as an old time pen and ink draftsman, I'm certain that trusting your "eye" to judge fit and fairness of the build is the surest guarantee of a good outcome. I've never seen a wooden boat builder who didn't follow the maxim, "build to the boat and not to the plans." There are so many curves and variables to the parts of a vessel and opportunities for compounding errors of measurement, it's a very difficult thing to reduce them all to dimensions having the accuracy tolerances that mimic the "interchangeable parts" processes of modern mass production. It makes perfect sense in theory, but never seems to work in practice with a "one off" build. 

[vaddoc]

27 minutes ago, Bob Cleek said:

never seems to work in practice

How true Bob! Nothing beats laying a baten on the hull. This was a lovely post, made me feel a bit like a shipwright of old!

 

[Bob Cleek]

4 hours ago, vaddoc said:

Nothing beats laying a baten on the hull.

 

Ain't that the truth! Maybe it's a generational thing, and I certainly can embrace many of the benefits of "the digitization of everything" (without which this forum wouldn't exist,) but I do think we do a disservice to the art of ship modeling by an inordinate focus on CAD and CNC machine tool applications at the expense of a sound grounding in how the vessels we seek to model were actually built in real life. I know I'm a Luddite, and old enough now that it doesn't matter, but as far as I know, nobody's yet invented a CAD program that can strike a fair curve as quickly, easily, accurately, and inexpensively, as a flexible batten of wood, nor a CNC machine tool that can cut a curved piece of wood to fit against its mate as quickly, easily, and inexpensively as a sharp edged tool in an experienced hand.  I, too, marvel at the "master machinists" who turn out perfect replicas using state-of-the-art digital age machinery (and I have a lot of tools myself,) but I lament the elevating of the technical above the artistic for therein lies the difference between an art and a craft.

Edited January 14, 2021 by Bob Cleek

[vaddoc]

The last couple of weeks I ve been very busy to work on the boat, just managing to post a bit here and there. Today however I made some

On 1/14/2021 at 3:32 AM, Bob Cleek said:

a flexible batten of wood

Bob, this one's for you my friend!

 

So, I first glued the transom in place. Now, I did not design things very well and frame 16 is in the way of the transom knee so the knee had to be made much shorter. It does not matter though, it is rigid enough, it will not be visible and I have accepted from the start that I ll cut corners on this boat.

I used epoxy thickened with gypsum. It actually is dead square but I think this is more luck than skill.

Now, I ve been trying to figure out the planking and there was something wrong with the rabet. Looking at the plans it should end at the junction of dead wood and horn timbers but I had it finishing further in. Easily extended with a sharp chisel.

Then I glued the frames to the keel and glued strips to secure all the frame cross members in one unit. Frame 2 is positioned wrong, it should rest on the little piece of wood on the left and not the stem. The difference is about 3 mm, I hope it is not going to be an issue. The frame cannot be moved, the epoxy has cured.

Now, the epoxy had not even hardened but I thought it is time to lay some batens on the hull to see how the planks would run. This is a strange boat to plank, I think the stern might even need stealers. I used pear strips 2 x 2 mm. Immediately things started taking shape. Doing this on CAD would need buckets of digital sweat!

I ll need to turn the boat upside down to better see things and most importantly, to define the sheer.

 

Regards

Vaddoc

[Bob Cleek]

2 hours ago, vaddoc said:

Bob, this one's for you my friend!

 

Happy to oblige! She's looking good! 

 

When you get to beveling your frame faces, take a wider batten and glue some sandpaper to one side of it. Chalk or paint the frame faces. Lay the sanding batten against the frames, bending it to contact the "high" frame face edges. Sand with the batten, watching the chalked or painted frame faces as the chalk or paint is sanded off. This will prevent sanding too much and removing the "low" side of the frame faces. This should give you a perfectly faired frame for planking. (And if you have low spots, glue on a piece of wood, or add a bit of filler paste, and then sand fair.)

 

It's a bit tricky working around the battens you have in place. You can remove one or two, sand that area, replace them, and move on to the next. You will find that tying the battens to the frames will greatly increase the rigidity of the frame structure. You don't want frames moving (or, God forbid, breaking) as you sand. Any string or wire will work to fasten the battens to the frames. I use pieces of telephone wire or the plastic ties they sell in gardening stores for wiring plants. Small "zip ties" work well, too.

 

When it's time to define your sheer, mark the points from your table of offsets or drawings, and then define the sheer with a batten, coming as close to the points as you can. Most often, the points defining the sheer aren't going to yield a perfectly fair sheerline. There's usually an inherent error at the ends.  The elevation drawing and offsets will accurately indicate the height of the sheer, looking at it in two dimensions straight on. However, because the side of the sheer is curved, the sheer is farther away from the viewer at the bow and stern than it is amidships, which is closer to the viewer. When building, one has to compensate for this optical illusion. Slightly more sheer is required at the bow and stern than may be indicated in the plans, so as to prevent the boat, now in three dimensions, from appearing to have a "flatter" sheer than the designer intended when the vessel is viewed. Trust your batten and your eye. If it looks good, it is good. Once you have the sheer defined on one side, it's easy enough to duplicate it on the other side by transferring the measurements from the first side to the second.

 

2 hours ago, vaddoc said:

I have accepted from the start that I ll cut corners on this boat.

 

You could have fooled me! It doesn't look like your cutting any corners that matter. This looks like it's going to be a very nice model and a model of a very refreshing subject! As impressive as they are, there's more to modeling than Seventeenth Century ships of the line! We need more models of working watercraft!

Edited January 28, 2021 by Bob Cleek

[vaddoc]

Thank Bob!

I am indeed cheating though, all the frames are already bevelled as the whole boat is designed on CAD. However CAD accuracy is now gone-old fashioned ship building from now on.

The sheer is also very accurately marked on the frames but I will use a batten for the final marking and let the wood find its own fair curve.

The batens are held with clamps as I just wanted to get an idea on the run of the planks. This will be a tricky boat to plank.

You are very right on the "exaggerated sheer". I followed the table of offsets and did not make any adjustments, I hope Chapelle took this into account...

[BobG]

Very nice work, vaddoc. She already looks lovely and you're just beginning!

[Jim Lad]

Don't know why I haven't picked up on this thread.  That's a great start you've made.

 

John

[Mark Pearse]

Hi Vaddoc, looking very good.

 

How does the line of the lower batten compare to setting out the garboard & then the first planks? 

 

Is this carvel planked?

[G.L.]

Smooth lines, Vaddoc!

[vaddoc]

Many thanks to all for your likes!

BobG, Jim, Mark and GL, your support is much appreciated!

Now Mark, it will indeed be carvel planked but in regards to the garboard please bear with me! It is coming (I think).

 

Be warned, this will be a long post!

 

Now, I have only a few moments to spare as work and family demand most of my time. I also need to shed some of the considerable weight I ve picked up during the lock downs which means cycling as much as possible, weather permitting. So I can only steal a few moments here and there to work on the boat.

 

For the last few days I ve been laying battens in all directions trying to understand the hull. It is a difficult one, there is a huge mismatch between stern and bow and the horn timbers are not helping either. There is also something strange happening with the fairing, the last two frames seem to have a disagreement with the transom-this can wait until the planking is figured out.

 

First, I properly defined the sheer. Despite the CAD plans and the accurate marking, the baten showed a slightly different sheer. It is pretty close though, almost identical in both sides and really fair. I also realised I can lift the boat of its cradle, it is very stiff. This helps to eyeball the lines of the hull.

 

The following photos are pics I took playing with the battens. The battens are stiff beech 4x2, quite reluctant to be edge bent.

 

Now, spilling planks, I probably could plank the boat in any way.  But this is the wrong way to do it-planks need to be realistic and cannot be overly curved. The plank stock in a real boat can be up to a certain width so the planks must be arranged in such a way as to minimise the curve of the planks. Of course, planks can be scarfed but with proper planning, this can be kept to a minimum. 

 

In the next photos, very wide strips are used to define the course straight planks would take on the hull. These are walnut, I think 10x0.5 or something similar

Now, beside the rabet and the sheer, there are two more lines that in this hull must be defined and respected as they will represent the edge of planks. One is the line that runs along the maximum curvature of the transom and frames. The other, starts from the point where the rabet at the deadwood meets the horn timbers (this must be an edge since the next plank will lie at a different angle) and continues towards the bow at a line where a straight plank would lie, essentially following the hollow of the turn of the keel. 

 

So with these two lines, we have now divided the hull in three zones. If we lay planks on these two lines, they should be more or less straight. That means that the rest of the planks that will fill the gaps, should need spilling but should not have an impossible curve.

Now, we can define the garboard. 

The lower zone really can be filled by only two planks, one will be the garboard. These will not be enough to cover the stern - we ll get to this later. Now, the upper edge of the garboard needs to be straight. So, if we lay a baten, from the middle of the zone at the stem, all the way to a reasonable width at the stern without the baten having any edge bend, we have the upper edge of our garboard. The other will of course be the rabet at the keel.

 

The next photos show how the garboard and first strake should go. It also shows how much the edge of the baten is raised on the initial marking of the run of the planks, which means that the spilling would need to be impossible.

The rest of the gaps will be divided to equal widths, lines will be drawn and faired and the corresponding planks will be spilled. These planks will need to be more narrow where the hull has a large curve.

 

The last thing remaining is the gap at the stern in the lower zone. This will need a stealer. I thought that stealers were not used in such small boats but I was mistaken-they do. Some images bellow

Also, a few pics I found that show how the planks meet the horn timber

Finally, this is a you tube video that I think is fantastic and explains the process in a very simple way.

https://www.youtube.com/watch?v=BpI7B43KA3I

 

One thing I need to be mindful of is the bevels of the edges of the plank. At this scale the planks will not sit well if they are simply cut vertically. Also, some planks will need to have the inner surface hollowed, this I am not sure how it can be done.

 

This is of course just a bit of initial planning but I think we should not be far off.

 

Regards

Vaddoc

[G.L.]

This is a very interesting and educational post. I am very curious how you will transfer the shape of the strakes to the real planks.
I am eager about the sequence of this thread.

[Wintergreen]

Interesting thoughts. 

 

About hollow planks, my take would be to glue sand paper to a piece of wood rounded to the approximate curve of the frame(s). Possibly with some steering aide to keep the sanding centered on the plank.

[wefalck]

My first thought also was, that there would be no stealers on (small) boats, they would be too narrow and short for secure fastening without the risk of splitting the wood.

 

How wide, do you think, your planks will be. Planks of 10 mm x 0.5 mm seem to me rather small at a 1:10 scale. I would imagine that planks would be at least 15 cm wide, if not 20 cm, and a couple of cm thick. That would give you more meat for fitting.

 

The hollowing out of the planks to fit the frames would have been done with either a plane or a spoke-sheave with rounded sole. I think you could find something suitable among the miniature planes luthiers have.