Pathfinder build

[Rik van der Vaart]

Ordered the plans from John Welsford a few days ago. Prepping the shed build and family for long build project. Very much looking forward to building her as she seems to be designed for me. Sturdy, beautiful and seaworthy without the heavy lead ballasts, it's a good thing she does not have a cabin (yet) so I can live aboard permanently

[David G]

Rik,

I'm biased, of course, but I think you picked a sterling design. Have fun... and I hope you'll be keeping us updated. Fotos are much appreciated around here!

[maarten]

Rik,
Didn't you bought the somes sound 12 plans already?
I did, but chikend out of building it.
At least for my first build.

[Rik van der Vaart]

Maarten,

Yes I did buy the Somes plans. That is a very beautiful boat which I may still make in the future for open ocean work. But the 600lbs ballasted keel scares me a bit since I do not have the skills to work with that type of weight (yet).

What did you build?

Groet,

Rik

[maarten]

Dito about the lead.
I am still contemplating a few boats.
And first need to finish the shed. (building doors right now)
My favorite at the moment is the Deer Isle Koster.

Groetjes,
Maarten

[Rik van der Vaart]

The first step is to build the shed in which to build my pathfinder. Bought 2x4s and cut the for a 24 x 9 foot workplace. The height will be 7 foot. The structure is able to hold more than 500 pounds so it will be able to lift the boat for flipping. The first rafters (triangle with one vertical post) is positioned. 1x2s will hold it all together and square and will hold the 6mil plastic sheeting in position during this project. To block sun and uv a blue tarp will function as roofing. The remaining 6 rafters will be fit tomorrow.
The space will have to do since there simply is no more space. The 6 foot beam gives me very little room to manouver. Wheels under the cradle may be the only solution.

[Rik van der Vaart]

The building shed is up. It will be able to lift the boat for flipping after I put up a 2x8 along the rafters and attach a pulley system with rope or bands to lift and rotate the hull when the time comes. The plans are still in transit from New Zeeland. I wish I knew what I could get done before they arrive since. I also wish I did not have so much other work to do (for which people pay me) so I could build boats all day... What is it that gives me this drive? Now the boat yard is ready, the size of the boat becomes clear. This is going to be a nice big boat. My 21 ft capri was larger, but the cabin took away cockpit space. The cockpit of this boat will be much larger and give a much larger-boat-feel I suspect. Reading Navigator and Pathfinder blogs and web pages give a lot of information but also more itch to start my project. My 5 year old assistant keeps asking for the name of the new boat and I keep telling her that this will come in time, even though I already have a name set for her. It is a boys' name though so it may change.

[WX]

Rik I just poured an 800 kg lead ballast today, you can see photos on my Redwing Update thread if you are interested.

[maarten]

Is this you're shed, Rik? (pic function not showin a pic)
I like the fact you can remove it when done. I'm afraid mine's there to stay.
To all lead pourers heads up. Big respect!

If it's you're shed this must be you're blog then. (pic's on the blog anyway)
http://pathfinderriksbuild.blogspot.com/

[Rik van der Vaart]

@maarten,
Yep, that is the shed, and the blog. Still waiting on the plans to arrive from NZ. Glad the shed can stay, not too much headwind from the family front. So the project is a definite GO.

[Rik van der Vaart]

It took a while, but finally, from the opposite side of the world, I received the plans to the Pathfinder. We can start. YES!

[Rik van der Vaart]

Setup the cradle and leveled it.

[Rik van der Vaart]

Cut the first piece of the boat; the stem parts. It took an hour to figure out and draw the stem on the ply sheet. Not all coordinates lined up very smooth without creating very strong bends. Ply can be shaved to fit easilly so it should not be an issue. The millimeters tollerance is very precise. My cutting is within 2 mm of the design so the fillings will have to do their job and make the joints perfect. Will wait to glue up the parts until all are cut. The doublers will be made from untreated 1x6 lumber.

Put the stem on the cradle... This boat will be nice and big!

[Rik van der Vaart]

Late yesterday I started on measuring the parts for frame #2 on the ply. But this did not go easy. Some numbers are very difficult to read and guessing them will give problems later. I think it may be easier to draw templates first and then outline these to the ply. The thickness of the sides is not on the drawing so I took the same thickness as the stem. Thickness of the arching top piece is also not noted on drawing so... I don't know. I feel demotivated because I do not have exact numbers. Maybe I need to stop worrying to be perfect and just do the best I can? "Best is enemy of good and good is good enough", something I heard a couple of times the last few days.

[P-man]

that sounds like information that should be provided by the designer. have you thoroughly reviewed all drawings and build instructions? sometimes information is located somewhere other than the drawing. isn't that a John Welsford design? i know he posts on the forum and i imagine he would be happy to answer any questions you might have.

good luck.

[keyhavenpotterer]

I love this design.

Can I be of any help with the numbers? My plans are clear, if your print copy is a bit faded maybe they are an old set or the printer machine was low in ink? Mine have numbers written in clearly over some older faded ones. How old are your plans? Mine maybe are a bit newer and have been re written by John in on the master set (its his hand writing not someone elses). Mine came from Fyne Boat Kits last summer. Maybe you need a new re written set?

It says side and bottom cross pieces of the frame 12.5mm ply, top piece two layers of 9mm...anything else not clear on it?

Ed

[Rik van der Vaart]

@P-man, info is provided by designer. This is a wonderful boat and very well designed by John Welsford. The copy I have shows numbers written over numbers, without grey shades so its black on black, making some digits completely unreadable. I have set-out some lines, including on the well documented forum of the designer, for answers and hope to get the right numbers. Maybe I should use my brain some more and try to deduct the dimensions somewhere else, like you mentioned. I would just hate to make a mistake unknowingly and find out by the time I put the planks on that I did...

@Ed, thanks for your offer to help. It is not the thickness of the ply, but the coordinates for the stem cutouts for the stringers which are confusing me. Which number of the two is the correct for each set? Also on the y axis of the stem #2, the numbers are overwritten so that I cannot know where the boundaries of the side parts are. Can you give these? On the bottom panel, near the chin, I see a "130" but it is not clear what this number is for, WL-130? The reason I am confused is because if the bottom panel is completely flat, and the center point is @ WL - 141, what is this number for? The horizontal coordinate for the bottom chine is (232,-141) or (232,-130)?

I love the Pathfinder's design and I just want to build it and sail it. Who said boatbuilding is easy? This figuring out is probably part of the process and forces me to think a little before I construct. John is a very wise man.

[keyhavenpotterer]

The 130 number must be the height of Bulkhead 2 1744mm along. At Bulkhead 2 the stem is 201 vertically (141 + 70). Total 341 from the horizontal axis.

Bulkhead 3 is 2460 along the horizontal grid. It's bottom point is 117mm up. On Bulkhead 3 the stem is 150+57 = 207. 207+ 117 = 324mm total to the top of the stem at Bulkhead 3 from horizontal axis. (John has written 323 at this point - only 1mm don't sweat that).

The horizontal co-ordinate for the bottom chine at Bulkhead 1 is 47
The horizontal co-ordinate for the bottom chine at Bulkhead 2 is 232.
The bottom panel near the 'chin' says its drawn on a 250mm grid.

The stem profile: stem is marked going up from the horizontal the stated amount. e.g. 200mm along the horizontal axis 428mm up...same deal up the verical axis 400mm up its 216 to the stem outer.

The intersection with the middle of the stringers is given as 562 - 707 - 862 - 1055. Just draw a line accross at this point. The top of the stem curves back a little and is 134 to the stem.

Overview - put the bottom board down on the correct curve. Make your bulkheads and make sure your stem fits YOUR bulkheads perfectly, for a perfect fit. The stem will also be supporting the front of the front cockpit deck. It's not a straight line it seems but has a curve fore and aft. Might have it wrong, but thats my interpretation. You can see that the stem goes from 189 to 201 to 207 tall at BH 1 - 2 - 3 respectively. Would you concur or have I got it wrong?

It'll be a great boat.

Ed.

[Rik van der Vaart]

Ed, thanks for your info on the bulkheads. What about the two number at the stem cutouts for the stringers?

Have you built your Pathfinder?

[keyhavenpotterer]

Nope so don't take what I say as gospel.

PM PaulG as he has for confirmation.

But I'd like one...got to finish my Shearwater, then build a Scamp and a Nautilus before a Pathfinder or a CY.


Mine has two numbers there. The 562 - 707 - 862- 1055 are in BOLD type and look like there supposed to be there and have a small tick by them. The 552 - 690 numbers are feint and personally I wouldn't go on. It'll all connect up once you loft it onto your plywood with a batten.

Remember make it all nice and fair and you'll be adjusting the stringers to make it look sweet later anyway. Especially on boats that carry beam forward you sometimes have to pull the sheer up right at the nose to make it avoid excessive powderhorn optically as the gunwales converge in.

I've looked at a good few of these, the top strake can look a bit bigger than the others, putting a bottom rub strake on the sheerstrake and painting it the same colour as the strake below the sheerstrake, takes height out of the top strake and seems to make it look more even to my eye.

This one has a lower rubstrake and it just makes the the top strake a bit smaller and well proportioned. This one is same wood as top rub rail/ gunawale.



Ed

[Rik van der Vaart]

Thanks a lot Ed! This is great info.

Rik

[keyhavenpotterer]

There's lots of build pics on Perry Burton's blog if you need to visualise how a Pathfinder slots together...






http://buildingpathfinder.blogspot.c...-paginate=true

Ed

[Rik van der Vaart]

Ed,
I got the stem numbers. On the vertical axis on Frame # 2 it has a number which I cannot read, it's either 550 or 590, right below the "711". Can you see what it is?

[keyhavenpotterer]

On mine it says 550 in bold black over 550 in very feint.

Frame points are -141/ 232, WL/ 442, 152/586, 315/688, 550/752, 711

A few Pathfinder owners have switched the mast to a deck stepped arrangement to aid lifting solid wood masts windy weather. If you do want this (and you can get a lighter alloy mast or hollow wood mast as an alternative approach) now's the time to consider beefing up Bulkhead 2's scantlings (under the mast base) for this purpose. I think somewhere on the jwbuilders Yahoo forum John Welsford gives the scantling increase but i can't find it..have a search if you want this.

Also some owners found a little spray water pooling in the front cockpit sides, so some have run copper pipe drains through to the aft cockpit, from where it can be pumped out to keep it dry and consider what side your most comfortbale helming and pulling the engine start chord to decide on the bulkhead motor mount arranged to port or starboard when you cut/ arrange that one, in case you'd prefer it on the other side, unless your going for an outboard bracket.

Ed

[Rik van der Vaart]

Ed,

I read Perry's blog many times and it is a great resource. If I ever get to assembly it will support my build a lot. Right now I just want to cut all pieces correctly. And your help was great. Without it I would not be able to proceed correctly. Thanks a million!!!

I also looked at the SCAMP but just love the design of the Pathfinder. It is a more complicated build but in the end I have to have a passion for the looks of the boat, which I do in Pathfinder's case. Right now I do not think there will be a third build for me but you never know.

Thanks for the heads-up on the choices. I intend to make hollow main mast which will set in the original Welsford arrangement, idem with the mizzen's mast. The copper pipe drains I will look into. I expect wet sailing here with high winds and good wave action. I will need all the water management I can get. My 2hp Honda will be mounted inside. I saw one build with a port side mount because the right hand start-pulling. I am sure John intended the starboard side mount for a reason. Until I know this reason I will keep this setup. With the speed I am working now it may take some time before the setup is final. All the parts of the frames will be glued together after everything is cut.

I appreciate your help very much Ed.

Rik

[Rik van der Vaart]

Most posters are of great skill and have much skill. Me, I come from self learnt carpentry wanting to get the function of what I build. Of course it needs to look good, be solid and function as intended. But what i see around on this forum is often close to wooden art. Cutting frames after reading dimensions on a plan I bought, days on end, I often feel very humble posting here.

Of the seven frames, for have now been cut. As accurately as possible the two halves were produced in an hour of work. Just keeping at it, may sound boring, but i am feeling that the boat's structural parts are getting done. We are half way. 3 More and the transom. Then the assembly of the frames and of the entire structure will start... Step by step.

Listened to Voyage in Desperate times From the goodoldboat website. Very nice story about the auxiliary coast guard during the 2nd WW. Well narrated and just a great story. True one also. Just like Trekka's story...

[Rik van der Vaart]

Finally continued the build. Rather, preparing the build; still cutting parts. Frame 6a has been cut. Not the stringers, not the doublers, just the frame. Had some doubts about the measurements on the drawings but these are sorted out thanks to JW and the building forum. The frames seem smaller than my imaginations tells me they should be if i look at the pics of the pathfinder. But the 17 ft 4" is pretty long and since i am used to only a small dinghy's dimensions my imagination does not mean much. Frame 7 and the transom are left to cut. Then assemble each frame, ready for final assy. The centerboard and trunk are the starting points for this final assy after which she should start to look like a boat.

[Paul G.]

If I was building this boat again I would do a couple of things differently.

Build it light, bottom in 9mm and planking in 6mm (with Johns approval of course)and avoid stringers or use the smallest I could manage.
Id use a steel plate centreboard and have a narrower centrecase. There is a lot of work in the board and I had to use extra ballast in mine.
I would separate out the buoyancy chambers, port stb aft fwd, as it stands theres one big one up front and 2 small one under the seats.
Outboard on a bracket, the well makes the boat into a box full of bees with the motor running. Less work too. I changed mine over after a while and I ended up using a 5 hp as motoring with a 2 into 20 knots and sloppy sea is a waste of time.
I'd consider carbon for the mast if I went for the gaffer but whatever material/construction to keep it as light as possible.
I went back to a yawl as its so handy, (but not a sprit boom)

Good boats, you'll love it.

[Rik van der Vaart]

Hi Paul,

Is this your website? Or is it coincedence? The boats don't look alike at all...
Thanks for your feedback and good ideas.

I have been doubting to allow for an outboard, in any case inside the vessel. With your experience in the bee hive, I will opt for no inside engine. If I will need an engine besides the sculling oar a bracket will be used.

I like the gaffer but not the sprit. For some reason a boom with lazy jacks is my preference. I wonder if the can make sails for the pathfinder like that, main with a gaff and boom, mizzensail and jib without changing the centerpoints of sails.

You created more buoyancy or just kept the same volume but created more chambers?

The centerboard and rudder will be made by laminating marine plywood to dimension specified. No way am I going to slap all those batons together just to sand them down again. I want to get to the water asap without rushing. I have seen many sailboats with centerboards and rudders made from ply and fiberglass and the stiffness and strength should suffice. With the belt-sander things should be ready quickly. The centerboard may receive some more lead than specified. Our winds here average around 20 knots all year round so I will need low centers of gravity. Added ballast around the centerboard is planned also.

Your tip on the stringers is also a good one. I think they are not there for joint strength but for base-alignment and filler. so they can be made 1cm thick max. I intend to rip them from a couple of 2x8x20ft with the grain vertical so that they bend really easy. Did that with my previous build and came out well. Needed some extra hands to hold the beams while I guided them through the table saw...

To keep it light I am intending to follow John's advise about not epoxying the inside and outside of the boat but just prime and paint it. Maybe a fiber-mat on the lower two panels and epoxy that mat of course so that I can beach her without any issues. What is your take on that?

[Paul G.]

Is this your website? Or is it coincedence? The boats don't look alike at all...
Thanks for your feedback and good ideas.

No its not me, but it gives you a good idea of whats involved.

I have been doubting to allow for an outboard, in any case inside the vessel. With your experience in the bee hive, I will opt for no inside engine. If I will need an engine besides the sculling oar a bracket will be used.

You wont regret that decision especially if you need to take a 3 hour trip to get home under motor

I like the gaffer but not the sprit. For some reason a boom with lazy jacks is my preference. I wonder if the can make sails for the pathfinder like that, main with a gaff and boom, mizzensail and jib without changing the centerpoints of sails.

The gaff rig is handsome and would be faster all round to handle as well as sail. Lazyjacks and a conventional boom are best if youre a serious salior and there is no problem ditching the sprit booms. I found the sprits to be clumsy to handle especially when you need to reef.

You created more buoyancy or just kept the same volume but created more chambers?

I built to plan, but if you think about it, if the main buoyancy chamber got holed thats more than 2/3rds of the total volume.

The centerboard and rudder will be made by laminating marine plywood to dimension specified. No way am I going to slap all those batons together just to sand them down again. I want to get to the water asap without rushing. I have seen many sailboats with centerboards and rudders made from ply and fiberglass and the stiffness and strength should suffice. With the belt-sander things should be ready quickly. The centerboard may receive some more lead than specified. Our winds here average around 20 knots all year round so I will need low centers of gravity. Added ballast around the centerboard is planned also.

If its windy you will need plenty of weight in the board, hence the suggestion of a heavy steel plate, 20 or even 25mm. If going for the wood CB then triple the lead, my board weighed 80 kg and i needed all of it. The strips for the rudder are easy, its the shaping which is the same for both ply and solid wood, I recommend solid wood.

Your tip on the stringers is also a good one. I think they are not there for joint strength but for base-alignment and filler. so they can be made 1cm thick max. I intend to rip them from a couple of 2x8x20ft with the grain vertical so that they bend really easy. Did that with my previous build and came out well. Needed some extra hands to hold the beams while I guided them through the table saw...

Good idea,

To keep it light I am intending to follow John's advise about not epoxying the inside and outside of the boat but just prime and paint it. Maybe a fiber-mat on the lower two panels and epoxy that mat of course so that I can beach her without any issues. What is your take on that?

Epoxy seal the interior of the tanks etc, 2 or 3 coats of neat epoxy- dont paint as its wont seal these areas. Paint the whole boat with 2 pot epoxy primer, as its an excellent filler/primer/waterproofer then either one or two pot on top of that. Same on the exterior, but glass only the bottom, glass the bottom chine edge with double bias heavy glass for abrasion, and the stem up to the bobstay fitting. If youre launching and retrieving onto a boat ramp and dont pull it up on rocky beaches I wouldnt even glass the bottom, just the chine edges. Any extra glassing is a total waste of time and money, I was over zealous and even glassed the deck! Two pot paint is my choice, it is 10 times better in durability, abrasion resistance etc, but harder to touchup.

[IanHowick]

If I was building this boat again I would do a couple of things differently.

Build it light, bottom in 9mm and planking in 6mm (with Johns approval of course)and avoid stringers or use the smallest I could manage.
Id use a steel plate centreboard and have a narrower centrecase. There is a lot of work in the board and I had to use extra ballast in mine.
I would separate out the buoyancy chambers, port stb aft fwd, as it stands theres one big one up front and 2 small one under the seats.
Outboard on a bracket, the well makes the boat into a box full of bees with the motor running. Less work too. I changed mine over after a while and I ended up using a 5 hp as motoring with a 2 into 20 knots and sloppy sea is a waste of time.
I'd consider carbon for the mast if I went for the gaffer but whatever material/construction to keep it as light as possible.
I went back to a yawl as its so handy, (but not a sprit boom)

Good boats, you'll love it.

Interesting to see you think it's worth it to build this boat as light as possible. I went to a lot of trouble to build my GIS yawl as light as possible (lots of paulownia and carbon spars), figured it was worth it to keep the in use weight under what I could wheel around on a little trolley on my own, or carry over rocks with someone at each end. Opens up lots of launch possibilities such as trundling along to the other end of a beach where there's some shelter from the surf before launching and also keeping the car off the salty boat ramp.

I had however thought that once you got beyond that weight threshold, and had to use a boat ramp/slide it off a trailer straight into the water, it didn't make much difference if it was 10 or 15 % heavier or lighter. The pathfinder at 220 kg is about three times the weight of my boat, so I wonder what you gain by making it a bit lighter.

Just curious as to how you see this, thanks.

Ian

[Paul G.]

Just curious as to how you see this, thanks.

I made the classic beginners mistake of thinking heavier is stronger, and stronger is better, sure it is but why not build it in 5mm steel if thats the case? Its just has to be strong enough for purpose.

Light weight equals less glue and timber so there is a cost saving, plus there is a significant performance gain and you can add the weight with personal gear instead. Its not a trad heavy planked fishing boat, its a ply camp cruiser which goes pretty good.

John also specifies making the frames out of 3 or more pieces, I think it is to save wastage, but for all the fiddling I would cut them out in one piece, the frames dont do a lot by themselves but by the time seat tops etc are attached its an amazingly strong and rigid construction method.

[Rik van der Vaart]

Frame 6a is actually frame 7 so all frames are cut now frame six (two parts) are cut. The transom was also cut from 9mm ply. I decided to fabricate the centerboard by laminating 4 plywood of 9 mm and one of 12 mm giving me practically the required thickness of 50 mm. I intend to fibermat and epoxy it liberally creating shell strength from foreign objects like rocks and anything else. The one piece 20 kg lead will be two sections of close to 20 kg each. With our 20+ knots ave wimds I will need all the lead as low as possible as i can get. Instead of one large patch of lead i will cut out two areas with a one cm border between to keep it together. Or think of another way of doubling the lead amount as low as possible in the centerboard.
The reason for a ply centerboard versus the 20x60 wood pieces is that these are not available on the island. If the marine ply is good for structural pieces and everything else, why not make the centerboard with it? It will be very stiff!
Next is glueing up the centerboard and getting the lead.

[Rik van der Vaart]

Read some more posts on this and the jw forums about rigs and ballasting. The sprit rig does seem to be the simplest and best for the pathfinder. Of course, this is why jw advises this rig. Instead of maxing the weight in the centerboard, making it tough to pull up, and possibly overpowering the rig as designed, it will not put in more lead than 30 kg. Jw advises ballasting around the centerboard but also mentions this for novices. It slows the movements, giving more reaction time to trim or luff up closer to the wind. But in my mind the extra weight in the boat will not keep it more upright by itself. Reefing the main and proper sailing does that. The moment of an extra 5 or 10 kg at 80 cm from the centerboard's pivot in the centerboard is same as 40 or 80 kg 10cm next to the centerboard, but worse for sailing performance.

[Paul G.]

The best rig is the one you like, I prefer conventional booms, far easier sail handling. I tried a gaff sprit yawl, a bermudan sloop and ended up with a bermudan yawl for simplicity, handiness and performance.. Weight in the boat next the cb is hopeless doesnt do much at all. 20 kts is windy enough for you to need a heavy board, 6:1 tackle will lift the board. As I mentioned my board was around 80 kg, and it made a significant difference.

[Rik van der Vaart]

Paul,

How did you get your board to 80 kg?

[Paul G.]

Paul,

How did you get your board to 80 kg?

I made and shaped the board, then I made box about a third the height of the board and filled it with cement and plunged the board in. Then i set up some threaded rod and poured the lead and bolted it to the board.

A 25 mm steel board would work well too!

[Rik van der Vaart]

Not having the specified materials for a centerboard, I am on a tangent to make it with ply. 5 Sheets, center one is 12mm, other four 9mm. The outer two will have a thin bracket to hold the lead in. The dimensions are higher than specified because I would like to approach 30kg ballast in the board. Pics show the dry fitted panels to be laminated together, followed by sanding down to the foil shape.


The sanding will be interesting since there is already a big gaping hole making for less sanding but possibly more difficulty getting everything to line up. Hopefully the veneers in the ply will assist with getting a nice foil. The artwork of my assistant will probably not survive the sanding process.

[Rik van der Vaart]

Used the planer and belt sander to create sort of a foil shape from the ply plank. Now it does look a lot like a centerboard but not to specs yet. It is a lot of work to get this to spec. It calls for .5 cm lagging edge thickness. Right now it is at 1 cm and at the higher section it is 1.5 cm. i wonder if it makes a big difference in sailing... Tomorrow i will finish it with a finer grit. The leading edge is round. The middle section is flat and the tail tapers evenly. To me that sounds cool. Will post some pics later.

[darroch]

Great picture to get your dreams started...just think of the adventures awaiting you at the end of your build!

[Rik van der Vaart]

Yes, that is a cool sight...

Here is the promised pic of the profile in the rough:

[Rik van der Vaart]

Not perfect but good enough. Sanded the cb more today with the random orbit, in the new clamp-grip Johnno recommended. Great tool for holding things while you work on them.




Yes, I have bought a couple of new tools for myself over the last months, figuring it makes a lot of sense investing in good stuff so that the boat comes out even better. But even with these tools, strange things happen. I found that the cb has a slight bend in it, lengthwise. it is about 4 mm lengthwise (1000mm). I do hope it will not make the boat veer off to some strange unintended direction and cause eddies which will make the magnetic poles shift around me. The only issue I have to watch are the tolerances of the cb casing.

Next up is the lead pour...

[Paul G.]

Have you checked the naca profile using a pattern from the drawing? You board does not look right and if you use a thick board it has to be correct. If you have a router you can do it easily

[Rik van der Vaart]

No naca profile, just a draft on the drawings. That router method does look easy enough. I need to find a better profile specification somewhere to make those rails and finetune the profile.
thanks for the feedback paul.

[Rik van der Vaart]

OK, it was not good enough. As the little voice in my head told me all along, others also reminded me that too thick of a cb is not going to work.
Researched about the optimal foil shape and got learnt about NACA foils, which some builders have used to shape their cb's. But in the end I decided to stick with my designer's specs, as close as I could.
So took of a bunch of meat of both the leading and trailing sections, narrowing down the leading edge to somewhere around 2cm radius and the trailing edge to 5mm, flat, leaving the thickest section 175mm from the leading edge at 5cm. It is still not a nc-produced piece but it is good.



Did not take this picture exactly from the bottom up but you can see the leading (right) and the trailing edges:


The trailing edge is pretty thin now:


The leading edge is also much narrower:


Now a quick break, weight the cb now and start setup for lead pour.

[Paul G.]

Its an improvement, but I still wouldnt pour the lead just yet. You have plenty of other jobs to do, come back to this later or nibble away at the shaping over a week or two. On the plan iirc john has a cb profile, make a 1/2 profile pattern out of plywood and put it over your board and get it right. The foil shape helps the boat to windward, if you don't do it well then you'd be better of with a thin steel board as all you are creating is lots of drag, you also have to consider the cb slot is huge and creates lots of drag as well so to justify the hole and get the max advantage of a shaped cb take your time. Pathfinders are not rocketships but they have a fairly modern underwater shape and they plane easily, mine was often cruising at 6-7 kts which is well above hull speed so efficiency of the foils is important.

[Rik van der Vaart]

Making planks, hollow masts, foils and rudders, none of these things I ever made before but they do not create a feeling of slight apprehension, to be modest. The humbling effects of creating a water-faring vessel are known to me and I enjoy the process. But to have to melt lead into a ballasted centerboard gave me the jeepers from even before I saw any sailboat design. Somehow the process just seemed insurmountably difficult. Even though I have seen many examples on the forums and websites. But It has been done. The centerboard now has around 30kg, still hot, added to its weight.

I purchased the lead from a scrap dealer here in the island for 1 dollar per kg. Pretty good deal I think. It was from roofing so had some tar and other adhesives and stuff attached. I figured that a non issue because it would boil off during the melting process.

Luckily the hardware store had exactly the right cooking apparatus I was looking for and got that for around 80 bucks. Propane tank hooked up, we were ready to go.

With my old fire retardant coveralls, boots, face protection, respirator, welding gloves and some cooking mints I borrowed from the kitchen I was ready. With a fire extinguisher nearby I fired the cooker up after checking for gas leaks. It took about 45 minutes before I saw a small pool of melted lead in the bottom of the pan, and was continuously adding small pieces of lead into the pan. After a short while all was melted and I test lifted the pan to see if I could easily handle it, without taking unnecessary risks.

The board was set level and supported for the to be added weight.



Not wanting to melt 30 kilos in one batch I decided to go for a two step process. The cavity was filled with the melted lead and all went well. Small boiling bubbles appeared from where the lead was poured and some popping occurred. But the board did not catch on fire nor did any other strange things happen, like lead pouring into my boots or something like that. Of course I was slightly stressed as this was the moment I was looking forward to... yeah right. But all went well, and I felt pretty excited.


So the second batch started up right away and all lead was melted in less than half an hour. I was more actively pushing the lead into the molted pool as to quicken the melting process. There was quite some junk I scooped out f the nicely looking metal pool, with a piece of wood. After the silver pool was pretty clean I went for the second pour.



That one also went flawless and the volume poured was exact. The lowest ends of the cavity are a few mm above the lead which is perfect. This will now be topped and faired with filler epoxy and covered with fiber.
I think the total is around 35 kilo now. Not sure, will weight the entire cb when cooled down.

So now I am having a (few) beer (s) and a cigar to celebrate this milestone. For others this may not be a big deal, but for me it is.

[Rik van der Vaart]

Paul, thanks for you reaction. I did make a half a profile of JW specs and used it to significantly reduce both leading and trailing edges. Most of the board is now per JW spec so I am OK with it. A steel cb would be great but I could not get that here in Aruba. I wanted to pass this station so I can make the cb casing and on with setting up the frames. If in the future I have another Pathfinder to compete against here I may just make myself a steel cb... but for now I am extremely pleased to have taken your advice and bring down the thickness in both ends of the cb.

[Paul G.]

Looking good, take your time remember you can always change things later if you want to experiment with more/less weight or different shapes.

[johnno]

Well done Rik, looking great. Enjoy that cigar!!