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

[Omega1234]

Hi Vaddoc

 

Great work! Bevelling the knees may sound obsessive, but who cares if no one can see them. Half the stuff we do in our models can't be seen, but there's no doubting the satisfaction we have in knowing that they're done.

 

Most importantly, however, congratulations on the incoming addition to the Vaddoc family!!! I wish you, your Admiral and new family all the best for a happy and healthy future together.

 

Cheers

 

Patrick

[garywatt]

The sanding machine a very good idea and i will be following your log

[vaddoc]

It works brilliantly Garry, it has become my main tool. Still on the original 120 grit paper!

[vaddoc]

Today was a challenging day. The drill press arrived but was faulty so had to go back. The proxxon unit though looks very solid and ideal for modelling. I really liked it.

Back to the boat, I was working on the deck assembly and realised a big problem. As it stands the main mast has very little support. 

Tad in his plans positions the main mast at station 0, where the cant frames are. 

 

 

 

This position looks to me too much forward and indeed the US team positioned the mast at frame 1. However, studying the photos it seems they used very thin profile wood for the beams and also secured one side of the mast partner to the side benches. They obviously knew what they were doing but still I wonder how the mast can cope.

 

 

 

Since I changed the thwart arrangement I cannot copy their design. I like the position of the main mast at frame 1 though. So back to the computer to arrange the beams for supporting the mast and the deck. The main problem are the cant frames and it was incredibly difficult to find an arrangement that would actually work in a full scale boat. Also, the deck is not horizontal but has a slope which added to the complexity. All beams had to be notched to accept one another. 

I am very happy with the result, it looks super strong and I am sure it would be fine in a real boat. Building to these plans of course is another issue.

 

Edited February 13, 2015 by vaddoc

[garywatt]

Hi Vaddoc,

 

i,ve download the plan for the future thank you,i like the idea for the pond pump my main hobby is koi keeping and yes would you believe it i have two large pump,s spare that idea,s been pinched lol and going to be used. You mention CAD do you have a site address i can download and learn everybody keep,s talking about it  i think it,s time i learn't to use it and hello Micheal don't worry i,m still going to follow your build till the end, Vaddoc keep up the good work i will be following to the end.

[vaddoc]

There are many CAD programs Gary, I use Rhino 5 because this is the one I had access to. I think they all are similar but be advised they can be very expensive, Rhino I think might run close to $1000. You also might need someone to get you started ( I had a friend who is an architect) and then on you ll figure things out yourself. I also tried some of the free ones on the net but did not like them. 

Regarding the blower for the saw, I now attached a lathe hose and the whole thing works very well.

 

 

 

[garywatt]

 

HI Vaddoc the hose idea is a good one and it will be pinched, i know this is cheeky will you be uploading any more plan,s so i can be storing away for the future, the build is looking good so far keep it up. i know it does n,t come up on my profile i,m Batley W/Yorks i dont know why my profile is not shown

[vaddoc]

Gary, I would like my CAD drawings to be put to good use rather than stay buried in a hard drive but that's for later, I would like to see first the project completed which will validate their accuracy.

 

Back to the boat, work has stopped as I am waiting for the replacement drill press. A lot of drilling is necessary at this stage and I resisted temptation to use the hand drill, the accuracy of the machine will be far superior.

 

A side project will be the making of oars and this is a project I was actually looking forward to. I am sure there are some guidelines regarding length etc but a quick search on the net did not produce a lot so I made an uneducated guess. I think a curved blade configuration with laminated maple and walnut would be nice, finished with Tung oil and Renaissance wax. I laminated a few pieces for oar No 1 (test oar if it goes wrong). 

 

 

 

[vaddoc]

Another task is the construction of the mast hoops. I had some 0.5 mm mahogany strips, I cut them lengthwise and used the hair thingy. I am thinking that gluing 2 or 3 loops together should produce a nice hoop.

 

 

[vaddoc]

I experimented with the hoops and oars (good title for a boating magazine). The hoop came out alright, although mahogany is a poor choice I think as it splinters a lot. I used it just because I had a few left over strips but I might order thin strips of another wood. The hoop on the photo has been sanded to 400 grit and had a coat of Tung oil.

 

 

 

The oar was much more challenging. The end result is horrible but I think that it could be done with a lot of patience, planning and attention to detail.

 

 

 

 

 

[vaddoc]

I had another go today making the oars. I watched a video on you tube of a company making high end oars and copied their method. I also found out the maths behind the length oars should have and for this boat its 32 cm, much longer than the first attempt.

 

First I made a rough pattern of the curve of the blade from scrap plywood.

 

 

Then I glued a small piece at the end of the long pieces that will later on be glued together. This because the end of the curve goes beyond the width of the strips. I used lime for two reasons, because it sands easily and also I have lots of it.

 

 

I then made some more pieces from the pattern. The darker ones are pear, but these are cut at an angle to the grain so that when all are laminated it will provide some strength against breaking.

 

 

All are glued together

 

 

And glued again

 

 

This is how it looks before the sanding spree

 

 

The  corners near the shaft where cut off and then carefully the oar was sanded into shape. The improvised table for the Dremel was very useful.

 

 

The blade was shaped first and then the shaft.

 

 

 

This is how the oar came out, it certainly looks better.

 

 

 

 

 

It took half a day to make one oar and the chances of all 6 coming out reasonably alike I think are slim. Might be better to go for flat ones which should be easier to make.

 

 

 

[Omega1234]

Hi Vaddoc

 

Nicely done with the oars!! If I were you, I'd persevere with the curved blades because they look better, are more challenging to construct and will give you greater satisfaction for a job well done once they're all finished.

 

My thoughts only, of course.

 

All the best!

 

Patrick

[vaddoc]

Grateful for the support Patrick! I agree with you, curved blade oars are nicer and probably the next ones will be easier to make but I need to find a way to ensure consistency. I should also try a flat one and see how it looks. Anyway, I will change focus for now and allow time for ideas to ripen.

 

My drill is here! It is really well made, spins very true, is quiet and easy to use. Highly recommended.

 

 

I finished glueing all the beams that are attached to the frames and sanded everything down to 400 grit

 

 

 

 

I planned to apply wax to all surfaces prior to assembly but it did not work very well, the surfaces are very complex and there is a risk to contaminate the surfaces that later on components will be glued. Also, sanding had produced some fine whitish streaks on the wood that I thought the wax would cover. This did not happen though. I am not sure what the cause is, I suspect these are scratches due to not changing the sand paper as often as I should. They are not a huge problem though, it still looks good. Another problem to sleep on.

 

The time has come to laminate the apron and for this all frames need to be erected. So I need to make some sort of jig. I do not have the equipment to produce the jigs I see the master modellers use so I have to improvise.

 

 

I have a lot of this nice wood which is really a fence bought from poundland. I did a bit of Zen and I think I can make the jig work.

 

Another picture of frames No 1 and 2. I am happy with the alignment of the components although I will not really know until the final assembly

 

 

 

[vaddoc]

The jig is progressing well. I plan to add later on longitudinal beams on each side at a height from the baseline and cross beams, 2 for each frame. It should be reasonably steady.

 

 

 

I need also to secure the stem and fine tune the bevel of the temporary mold at station 0 that later on will be replaced by the cant frames.

 

 

The centerboard case is also progressing and coming out very nice, I think it will be the best part of the boat!

 

 

I am certain the next big difficulty will be bevelling the apron and the stem to accept the bottom plywood panel which is essentially the garboard plank. The apron will have a thickness of 3 mm so it cannot be beveled like the keel of large boats. I also plan to laminate a false stem. 

[vaddoc]

I think this might be a milestone. We have a first glimpse of the hull lines!

 

 

 

 

 

A strip shows the keel line, it touches all frames and I think is as good as I could ever get it.

 

 

 

 

I also attempted to fit one of the planks. This is the lowest plank, it is rough fitted as it will touch the lower strake plywood panel.

 

 

My first impression is that the plank touches all frames effortlessly and the bevels are correct, the notches on the frames are also at the correct heights, I am amazed with the accuracy.

 

 

 

 

 

 

I added another plank, again it seems to fit ok. i am very happy that the two planks stay in contact throughout their length.

 

 

 

Now the more delicate work begins, too many bevels and plank overlaps to tackle!

[michael mott]

It is great to see the hull shape beginning to take form, nicely done.

 

Michael

[druxey]

Sweet!

[Omega1234]

Hi Vaddoc

 

Brilliant stuff. It's great to reach the framing stage, because you can now start to see your hard work paying off now.

 

Cheers and all the best

 

Patrick

Edited February 22, 2015 by Omega1234

[vaddoc]

Thank you all, your support is much appreciated. There are still many difficulties ahead!

 

I got very worried yesterday, I test fitted the outer sheer clamp and it was way off. I looked at the CAD designs again and realised that indeed I faired the sheer line in all views, however due to the lapstrake and the planks overlapping and not staying parallel to the frame, the plank to be used as outer clamp in order to follow the sheer needs to bent not only along the beam of the boat but also vertically along its own width. 

 

I did a bit of internet search and still the way the sheer line is faired is a mystery to me. It seems that all boat builders erect the frames and then just bent a batten that easily follows the sheer. 

 

However the solution appeared miraculously today. I continued work on the jig and glued supports for the longitudinal beams of the jig. I also screwed small pieces of plywood to stop the frames from lifting. I tested again the sheer and somehow it was fine.

 

 

 

 

I also glued the templates for bevelling the stem. I am almost scared to do it but it needs to be done as the laminate is too hard to sand completely with files. The problem is I will not know whether the bevel is correct until the very last moment, when it will be impossible to re-do the stem. The sheer clamp runs true to the stem on the photos, I have allowed some excess to be trimmed in the end.

 

 

 

 

[vaddoc]

Work is progressing slowly, due to other commitments and also because I am unsure of how to proceed further, these are uncharted waters. I think that these should be the next steps:

 

1. Secure the frames to the jig and laminate the apron

2. Remove the frames, cut frames 4 and 5 to allow fitting of the centerboard case , deepen the notches for the outer clamps in all frames

3. Re-mount frames on the jig, install the outer clamps, install the centerboard case (how?)

4. Install the garboard plywood sheet, this will require bevelling of the apron (how?)

 

Easier said than done!

 

First thing's first so here it goes.

 

I tried to make sure the frames are vertical to the floor which is of course the top of my workbench. I modified a key ring sprit level by gluing it to a flat piece of plastic

 

 

I then started adjusting each frame, but something was wrong.

 

 

 

 

It took a long time to realise that my bench top was not horizontal by far. I had to use my modelling jack to square things up

 

 

After this things went smoothly. I used rubber bands to attach the frames to the jig. The scaffold is screwed to the pillars so it can be removed and re-installed if necessary without loosing alignment.

 

 

 

 

I found a way to secure temporarily the stem. I also beveled the stem which was much easier than I thought.

 

 

The built is becoming too complex though and complexity is usually bad news. Anyway, I am ready to laminate the apron

[Omega1234]

Hi Vaddoc

 

Wow!!! Your work is always methodical and very precise. I also like your attitude in ensuring that everything is correct and well researched. Now, that's dedication.

 

Also, your building jig is a model in its own right! She's a beauty too.

 

Well done.

 

Cheers

 

Patrick

[vaddoc]

Thanks for the support Patrick, I never expected this simple boat to be so complicated and challenging. This is only my second boat and I have very little experience but I think that the curved keel and the centerboard add a huge amount of complexity. This boat needs to be held up in the air to be built!

 

I was reading various posts on the forum yesterday and I came across I think Chuck suggesting to pre-bent the planks to avoid lifting. I decided to do the same with the outer sheer clamps.

 

The next photo shows the upper most plank, I marked the sheer pattern and used it to secure the wet outer clamps and then used a hairdryer to dry them. I included some overcorrection to compensate for spring-back. I have not test fitted them yet but they should be fine.

 

 

 

 

 

At this time I had to face the fact that the time for hard decisions and action has come. The keel needs to be laminated but if I do this first it will be impossible to install the Centerboard case. Viseversa, Installing the Centerboard case would be very difficult as the boat is being built upside down and the frames No 4 and 5 would need to be cut which means they would become unstable and loose alignment. This is a puzzle but it is clear the only way out is to do something irreversible!

 

The american team installed first the centerboard case. Their jig is sadly much simpler!

 

 

 

So the decision was made: cut the frames. I used 3mm liteply to try and stiffen up the cut frames, this did not work very well but still kept the frames aligned. I did not cut the other frame all the way. According to my plans one of the frames should have a small step.

 

 

 

 

 

To install the centerboard some of the transverse beams had to be cut The jig had to be further reinforced so I glued scrap pieces of MDF and wood.

 

 

The next photo shows a floor suspended at the level where the top of the CB case should be

 

 

The beams where cut away. I actually cut by mistake the beam at station 2 but this did not matter. The jig is still super stiff

 

 

I test fitted the CB case and it is clear the frames need to be cut all the way as it still sits very high

 

 

After some careful sanding everything somehow fell into place. The CB case rests on frame No 3, the reenforcing planks are square with the frames and the 2 small planks that run either way of the upper margin of the CB case and extend aft to meat the support of the thwart actually do so.

The centerboard case according to Tads plans extends a little to the Apron for added stiffness. I think this is immensely difficult to achieve in this scale.

 

 

 

The next photos show the junction of the CB case with frames 3, 4 and 5

 

 

 

 

I carefully trimmed the excess case off. Everything seem to sit flush, I fitted a maple strip to make it easier to see the fit. All seem reasonably centered. The last photo shows the two planks reaching the thwart support.

 

 

 

 

 

Next task to carefully glue with epoxy, maybe thickened with pearwood saw dust. I will need to make sure no glue appears above the floor line and first I need to open the hole for the centerboard pivot.

[SailorGreg]

Coming along nicely.  It's interesting to see how you fix each problem as it comes along.  It also gives heart to those of us who seem unable to plan ahead and are forever running into the "what the heck should I do now? " question.

 

Just a thought - I'm not sure how rigid your centreboard case is but might it be worth packing it with some scrap cut to a snug sliding fit.  This will stop any movement or distortion as you push and pull and clamp and glue to get the planking in place.  It will also stop glue dribbles, dust and spiders getting inside!

 

Greg

[vaddoc]

Hi Greg, I think that designing the whole boat on CAD helped a lot as I understood the plans much better.

The Centerboard case is very sturdy and the fit already snag but your suggestion is good, packing the case will assist in gluing the mid portion of the case to the frame, although it could also slightly distort the unstable frame. 

The outer clamps will be added, then the apron and then the bottom panels. At this stage the hull should be rigid enough and it might be even possible to rotate it to apply epoxy filleting and the transom knee. The US team used epoxy, although Tad designed it epoxy-free with just rivets. No harm in overbuilding though!

[vaddoc]

Progress has been very slow recently as I am really struggling with the keel, the bevel it should have and the shape of the bottom panel.

I finished the CB case and installed it. 

 

 

 

 

I first used epoxy to glue the case to the frames. I tried packing the case but it distorted the frames. I was very careful with the epoxy as it is a very messy glue.

 

 

I also added the outer clamps and glued the stem to frame No 1

 

 

I then reinforced the CB case with epoxy filets. It looks a bit messy but all these will be covered by the floor boards.

 

 

 

 

 

In my CAD plans I designed the bottom panels but did not take into account that the rabbet line is not straight but widens at the centerboard. Also, the panels need a lot of bevelling where they meet the next panel towards the sheer. Overall I still have not pinned down the right shape.

 

 

 

I have lined how much I think needs to be removed

 

 

I attached the outer clamps to the stem

 

 

 

Next I started laminating the stem. The plans call for 16 mm wide strips and I could only get this dimension in walnut 1 mm thick. The overall thickness of the stem is 3 mm and I think that the resulting 2 layers of epoxy might not be enough to provide rigidity. I managed to find 0.5 mm maple sheet to cut strips for the laminate which will double the epoxy layers.

I will first laminate the first 2 mm, bevel these and then add the last 1 mm which will be shaped as the keel. I am hoping the bottom panels will then fit flush sitting nicely on the bevels. 

The american group did something similar

 

 

 

It will not work of course as it is far too optimistic a plan but I will give it my best shot. Besides, this is what I would do building the full scale boat.

The first strip 1mm thick is epoxied into place. The transition from the last frame to the Transom does not look too faired but it is too late now.

 

 

 

Preparing to laminate the rest of the layers

 

 

You can never have enough clamps

 

 

The hull should now be very rigid. I will probably add another strip to connect all frames (beyond the sheer line) to strengthen the structure even further and remove the cross beams of the jig. The stem will probably need some form of re-enforcement as well. 

Things are getting very complex and difficult now. And with all the epoxied parts there is no going back!

[vaddoc]

On a different note, I do not think there are any copyright issues from the photos I uploaded.

I think I should add the sites for reference

Tad's site

http://www.tadroberts.ca/

The american group's site

http://www.boatproject.org/#628

If there are any issues I would be grateful if the moderators would remove material appropriately

Edited March 7, 2015 by vaddoc

[vaddoc]

Actually, I just realised that the jig needs to be cut to be removed as the apron is now in place. Also the hull looks really solid, so I just glued some more wood to strengthen the jig prior to cutting as it may ned to be used again.

 

The epoxy has partially cured so I removed the plastic bag for a couple more pics

 

 

[druxey]

I think you have it (clothes) pegged as well as nailed! Your 'messy' c/b is most other folk's neat, Vaddoc. And as far as the skin is concerned, it's always better to have wood to remove rather than have too little!

[Omega1234]

Good stuff, Vaddoc! It looks like you're not far off seeing your framework transform itself into a beautiful hull....and when that happens, you can look back and admire all your hard work.

 

I'm looking forward to more updates.

 

All the best

 

Patrick

[vaddoc]

Thank you both, hard work indeed!

I did some more work today on the apron. I first bevelled the junctions to the frames and then connected the dots. The different colour layers of the laminate help figure out how much wood to take.

 

 

 

 

 

 

 

One side done

 

 

The bottom panel finally looks like it has the correct shape. 

 

 

 

 

I did the other side and I am happy with the result. It is not a close fit as there is up to a mm gap here and there but I think it should be fine with some filler.

 

 

 

There are a few problems though

1. The overlap of the planking should gradually fade as it approaches the bow so some bevelling is needed

2. A lot of bevelling is needed and probably wood removed where it meets the next panel towards the sheer

3. I used 1 mm plywood but still it is very unwilling to take the sharp bent at the bow. Maybe 0.8 mm would be preferable

4. I am not sure how to keep the plywood panel in position until the epoxy cures

 

Certainly though, there is progress!