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Jonathon Gillham

Racing Sparrow RS750

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So this really started a few months ago when I was talking to my 5yo son and we made a treasure chest out of a shoe box.  He talked about things we could make and I said we could make a boat one day when he was a bit older.  I made a hydroplane when I was about 14 and used all the gear from my Boomerang so sort of knew what I needed to do.  He persisted and so we made a monohull powerboat which is finished now, and that got me thinking.  During the research for the first boat I stumbled across www.racingsparrow.co.nz and the site intrigued me.  I bought the book which is a step by step instruction on how to make a yacht and knew that I would end up building one, and here I am.

 

 

This is all new to me as everything about this boat is built from scratch so there is no hiding anything.  Still, it should be a lot of fun and I’m hoping that it will take about 100hours so should be much better value than a Top Force, which would cost about the same.

 

 

First up, a trip to the LHS for supplies.  I did consider other options for the supplies but the guy at my LHS really knows his stuff, so even if I could save some money by buying online it wouldn’t be worth it.  I took the book in and he went through the list and supplied what he could, and gave advice about what he couldn’t supply.  Most of it is easy to source but there are a couple of things which are proving challenging.  The mast is 1045mm long, and most metal tubes are 3 feet or 1m long.

 

 

Another important thing to decide is what it will look like.  I toyed with a few ideas and ended up deciding on NZL20 Kiwi Magic, which was New Zealand Challenge’s 1992 America’s Cup entrant.  Its probably my favourite of all New Zealand’s America’s Cup boats.  It has a small bowsprit which ultimately lost us the challenger series.  We were 4 – 1 up in the final when the Italian syndicate protested the use of the bowsprit and won.  We were docked a point and no longer allowed to use it which affected the performance of the yacht and we lost the next 4 races to lose 3- 5.  All that it means for this build is the colour and the way I shape the bow and stern and of course paint it.

 

http://www.americas-cup-history.at/english/nzl-20 kiwi m 92.htm

Getting started

Reading the book is great, but it refers to the big plan all the time.  I thought about getting it printed but A1 is near impossible to find so I ended up printing it on A4 sheets and taping it together.  This will work fine and I made sure the top diagram is lined up correctly as that’s the one that I need to take measurements off.  I then needed to make sure that the formers were the right size which took a bit of playing around with sizing on the printer.  I ended up printing them at 108% and they came out marginally larger than they should but that is fine for this build since I need to sand them down as well.  I also glued the 2 75mm pieces together to make the 150mm wide one that I need which would be ready for the next day.

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Formers

There are a number of methods to cut the formers out.  The book suggests marking dots from the paper templates and drawing a line to join them by hand.  I tried this and its not for me.  I have read that spray on contact adhesive is the way to go and think this would be the best option, but that would mean going out and I really can’t be bothered, so I resorted to my tried and tested pinning the template to the wood.  This works fine.

 

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Once the formers are cut out then I had to sand them to get them ready for the strip planking.  This was a straight forward job, with former B requiring special attention to get a good shape.  The rest were fine although later on when doing the planking I realised I could have done some sanding when the formers were glued to the backbone.  This way I could have put a bit of shape into them so the planks are flush on them with the full 5mm contact point, rather than sticking onto part the former only.

 

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Backbone

Next was cutting the backbone and gluing the formers to it, and this is where I made my first and second mistakes.  Everything was perfect as far as spacing etc goes and these mistake weren’t fatal, but I should have made sure that I centered the formers when gluing to the backbone, so an equal amount of backbone was sticking out fore and aft because you need to use the backbone to make a bend in the boat.  The other thing was gluing the nose bulkhead along its whole length, when of course you have to remove the backbone later and a few dots would’ve held it.

 

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You then place a bit of balsa under the backbone in the centre to create a curve in the hull, with weights at either end.

Strip Planking

The next step is the strip planking, which is about the most rewarding thing you can ever do in your life ever.  Without exception.  Unless my son turns out to be the Black Caps captain, then all those nights in the backyard playing cricket would be more rewarding.  But really, what are the chances of that?  (very high as hes off to the paras at 18 if he isn’t in the Black Caps)  (wait my wife might read this, he can do whatever he wants with his life and we’ll support him).  There is a tedious part which is cutting the planks, you have to cut 4mm strips from a plank of balsa and that isn’t easy.  Well, it isn’t hard either, it just takes patience.  I asked my wife if she wanted a turn and she didn’t, but she really likes the boat build and has even sent a picture to a friend. 

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Once the planks are cut strip planking is amazing.  You glue and pin each plank on next to the previous one and get this fantastic hull shape.  The books tells you to put 2 planks on the keel line first, then single planks halfway down each side to split it in half, then a plank on the deck line.  Now that its nicely divided into sections you plank each section in turn.  This is wise, as by splitting it you end up with a far better hull than if you just started planking from the deck line.  When you get to overlapping planks you simply mark your cuts and cut angles – I only messed up 2 so it must be easy right?!

 

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So far all of this took a week doing roughly 2 hours a day.

 

Preparing the hull for fibreglass

This is pretty straightforward, you just need to cut the backbone off, trim the bow and stern and then sand it to a reasonably smooth finish.  The bow is left flat like that as you glass it then make a balsa bow and glue it on.  This is so if you collide with someone else the bow won’t do any damage to the other boat, and it doesn’t matter if you lose the balsa bow as the boat is sealed without it.

 

Trimming the stern was a bit fiddly as the hull doesn’t sit still, and its easy to break off a plank.  It would have been a lot easier if I wasn’t trying to measure to get the right shape for NZL20 and I just cut a straight line.

 

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I found sanding hard because the planks would flex in the middle.  I ended up running some glue on the inside of the hull halfway between the formers with the idea being to glue the planks to each other.  It did the trick and made sanding a lot easier.

 

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This is how it sits now and I’m really writing this to procrastinate.  I have never fibreglassed anything and thought I was saved by the weather, but its much warmer than expected so I guess I should go and give it a go…

 

 

 

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My grandfather was an avid wooden ship modeler. This brings back memories. You're doing a great job!

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This is brilliant, great work and write up. Reminds me of building small balsa rubber band powered planes from my youth. Love seeing how a 2d plan forms into a 3d vehicle, think I'd be nervous of fibreglassing too however! 

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One thing I found when I got my first RC boat is:

Don’t put it in the water if your not prepared to go for a swim to get the f’ing thing. 

But impressive build, not sure I’m patient enough for that! 

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@Jonathon Gillham - Nice! I've subscribed to your build thread. Currently in the same boat (Lol) with a Racing Sparrow 750 as well, although, not as far along. I have the bulkheads tacked down to the jig, awaiting stringers.

I've been building RC boats since the late '70s, have several 1/10 scale vintage scale hydroplanes, F1 hulls. The Racing Sparrow intrigued me, so off I went. The project has been stalled for some time, but maybe I'll get back into it soon.

ps... while purchasing rigging parts through Atomikrc, the Dragon Force RG65 main and jig boom gear I bought has been sitting as well. What do you know, the carbon fibre boom is 4.9mm OD, perfect to make carbon gear shafts for my M05 Ver.II build! =)

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Thanks for the comments guys.

@studioRS you should post up some pics when you get a chance, I'd be keen to see the right way to do things!

I've made some more progress since the last post and thought I'd try to keep the updates more regular.

Fibreglassing

This was the most intimidating part, so far.  Its actually reasonably easy, you just need a bit of patience and attention to detail, but its starting it that is the problem.  You have about 30mins to work with the resin too so that’s plenty of time.  I was able to do the whole boat in about 20mins which included a lot of going over it and making sure there weren’t any air bubbles.  It was also something that was much easier each time.

 

I did 4 layers, with the 1st and 4th being sheets covering the whole hull, and the other 2 covering about 2/3.  This means the keel, bow and stern all have 4 layers of fibreglass but the sides have 3.  The book just says one layer, but it also doesn’t specify the weight of the cloth so I went with what I was told in the LHS as the cloth I have is very light.  He actually said to do 4 layers with each overlapping the centre, so the keel line gets 4 layers and each side get 2, so I guess I did a hybrid of the 2.

 

The book said to layer the resin on first and then place the sheet compared to the advice from the LHS which was place the sheet on and then coat in resin.  I prefer the second method, as when I did it the other way I found it hard to position the sheet properly and ended up with it just missing the top of the hull.  I also tried using pegs to keep the cloth on the bow better but it caused a bubble along the keel so won't be doing that again.  I didn't get too many pics as its hard to take photos while wearing gloves which are covered in resin.

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I tidied it up after the first attempt with sandpaper, which I thought was important as there were a few bubbles or creases in the sheet, so I thought it best to sand these off, effectively removing the fibreglass, but then covering it properly next time.  If I had layered up a bubble then I would have ended up sanding through it at the end when cleaning up the hull.  I didn’t sand between the 2nd and 3rd coats, but did a tidy up before the final layer. 20181102_12052920181102_120529

 

Its currently curing and is ready to sand within 2 hours, but I will leave this one for 6 – 8 hours before no doubt not being able to help myself and start trimming it tonight.

Keel bulb

You need to cast your own keep bulb in lead.  To do this you make a balsa bulb which you use to make a mould out of plaster of paris, and then melt lead and pour it in.  Simple right?  I have a friend who has asked if he can come when I pour the lead and I’m going to take him up on his offer, partly because he might make himself a keel bulb and then he has to make a boat right?

 

The plan gives the profile of the bulb and says its 30mm at the thickest point.  I cut out 7 of the shapes slightly bigger than the plan’s profile and glued them together.  I will start carving this to get a good shape, and no doubt use some filler to perfect it.  I figure that the better I can make the bulb the better the mould will be and hopefully the better the lead bulb, but who knows.

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So thats it for now.  Tomorrow will be tidying up the hull and shaping the keel bulb.  I really need to sort out what aluminium I am going to use to make the keel too, with convenience no doubt winning...

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3 hours ago, Jason1145 said:

Go for a Tamiya Blue Aluminium ;)

I would, but the aluminium is hidden inside balsa and fibreglass...but then I would know its there, and it may qualify as a Tamiya then?

Was talking to a friend who works for a sign company. Hes going to cut me out the masking stuff I need for thr final painting, score!

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@Jonathon Gillham - Looking good!

Your are light years ahead of me on progress, so I'll have to follow your lead. Your Sparrow looks really nice. Personally I will keep some of the clear wood finish hull look, maybe a white top deck or racing line of red and white.

My only suggestion for would be two layers of glass, that should be fine. Note: also depends on the weight of glass and what type of resin or if you used epoxy, after two layers dry up, test for stiffness. I like to use a light spray of 3M Super77 spray glue to tack down the glass, this keeps it from moving and allows you to stretch and fit the curves, shapes much better. Then coat with epoxy or polyester resin. Think like you are building a scale racing sailplane for the water...

I prefer to use epoxy, my source is System Three.
https://www.systemthree.com/products/general-purpose-epoxy-resin

(here's a project I've done — covered a 2m EPO foam scale sailplane with 3M Super77 spray glue and cotton bed sheet cloth, filled with water based wall spackle, then soaked with CA glue, painted and applied stickers. https://www.rcgroups.com/forums/showthread.php?1494472-ST-Models-ASW-28-detailing-and-scale-graphics-project  )

About the only update I could give you on the progress of my build is how well the Dragon Force RG65 carbon boom works in my M05 Pro and MF-01X projects... Lol.

Cheers, Thompson

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A few months back, I picked up a 12 inch canoe kit off eBay. It was an unbuilt kit from the 1990's. My plan was to carry it on the top of a crawler. I've never built a boat like this before, so naturally I thought, how hard can this be? I opened the box and found a bunch of strips of wood and a diagram. :blink: I then put the lid back on the box, and it's been on the shelf since.  

This build thread has been helpful as I now see how things are supposed to go together. What kind of glue did you use? Are the pins easy to push through the wood without splitting the wood?

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I'll try to help with glue aspect, what works well on balsa for me is Gorilla Wood Glue. This holds to balsa really well and dries almost clear. Out of all the PVA glues, this sets the fastest. Super reinforcing too. (note: jump in the hot tub time machine and zip back to kindergarten, lots of glue on your fingertips — the after effect — you'll love to peel it off!). I've used this on my 1/4 scale 1954 Bergfalke sailplane.

Another glue that works well for Balsa is UHU Hart. Smelly, and with vapor, but works.

Another, medium CA glue.  I think it soaks into the wood too much and to make it work well you have to use CA kicker. However, it will be the lightest. This will also give you the quickest setting time of almost instantly. Keep in mind you are just framing up the hull structure. The real strength will be in the fiberglassed shell, the bulkheads (after outside glassing, some of the interior section of these wood bulkheads can be removed) and stepped mast which should be glued in with epoxy and glass.

 

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2 hours ago, Kingfisher said:

A few months back, I picked up a 12 inch canoe kit off eBay. It was an unbuilt kit from the 1990's. My plan was to carry it on the top of a crawler. I've never built a boat like this before, so naturally I thought, how hard can this be? I opened the box and found a bunch of strips of wood and a diagram. :blink: I then put the lid back on the box, and it's been on the shelf since.  

This build thread has been helpful as I now see how things are supposed to go together. What kind of glue did you use? Are the pins easy to push through the wood without splitting the wood?

I've used balsa instant cement (basically CA super glue) and PVA. The instant cement is good for internal stuff but dries really hard and cant be sanded. The PVA is much better for external stuff as it doesn't form little hard bits that you're then stuck with.

Yep the pins are dead easy, just push them in. For the thin planks and going into the edge of the formers its best to centre them obviously, but you don't have any issues really. The only thing is get the thin sewing pins, i tried drawing pins because i didn't have the sewing ones and they were so thick they caused problems. 

Also, studioRS knows far more about this than me so really what he said

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@studioRS what do you know about fairing compound? The guy at the LHS didn't have fairing compound (the bubbles to add to the epoxy) and said I could use builders bog instead. The hull is fibreglassed now and needs smoothing out, would you get fairing compound or just use the bog? 

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@Jonathon Gillham - Did you use polyester resin or epoxy for the fiberglassing?

I've used different methods of thicken agent for sanding epoxy such as super fine sawdust (on hand!), chopped fine glass, baby powder, to micro balloons. I don't think you need to use builders bog. Even try out some flour, gluten free? =). Mix up what you've got on hand and test it out with the sanding properties, this is always my best recommendation. You want to mix it so it won't sag when curing. Epoxy heats up while curing, so need to take that into consideration with what you use, baked gluten free flour Lol... =) Otherwise, you can buy some specific micro balloons or other medium for your use. If you've used polyester resin to lay down the fiberglass, definitely stick with this, don't use epoxy over it, won't stick and vice versa.

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15 minutes ago, studioRS said:

@Jonathon Gillham - Did you use polyester resin or epoxy for the fiberglassing?

I've used different methods of thicken agent for sanding epoxy such as super fine sawdust (on hand!), chopped fine glass, baby powder, to micro balloons. I don't think you need to use builders bog. Even try out some flour, gluten free? =). Mix up what you've got on hand and test it out with the sanding properties, this is always my best recommendation. You want to mix it so it won't sag when curing. Epoxy heats up while curing, so need to take that into consideration with what you use, baked gluten free flour Lol... =) Otherwise, you can buy some specific micro balloons or other medium for your use. If you've used polyester resin to lay down the fiberglass, definitely stick with this, don't use epoxy over it, won't stick and vice versa.

I used epoxy so thats a start!

I have been trying to research this and see people use talcum powder, sawdust etc, not come across flour yet though. I have builders bog and have used it a lot in the past which is why thats appealing, my main concern is weight. My understanding is the microballoons etc used in fairing compounds are designed to be light and bog probably isn't light.

There is enough strength from the fibreglass so its just to get a smooth finish. I've sanded the hull a bit to take the tops off some of the high points but want to fill from here so I don't weaken it. Also have the spray putty/primer filler stuff for the final finish to get it super smooth.

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1 hour ago, Jonathon Gillham said:

I used epoxy so thats a start!

I have been trying to research this and see people use talcum powder, sawdust etc, not come across flour yet though. I have builders bog and have used it a lot in the past which is why thats appealing, my main concern is weight. My understanding is the microballoons etc used in fairing compounds are designed to be light and bog probably isn't light.

There is enough strength from the fibreglass so its just to get a smooth finish. I've sanded the hull a bit to take the tops off some of the high points but want to fill from here so I don't weaken it. Also have the spray putty/primer filler stuff for the final finish to get it super smooth.

So now a cooking show — Top Chef Tamiya Club! Of course, all taken with a grain of salt, gluten free flour was supposed to be a jk 'just kidding' moment as epoxy heats up when curing...  Yes, most of the filet medium has always been considered for the lighter side use in sailplanes, air, etc.

Sounds nice on the filler, you'll find it easier to see all the undulations and bumps after a few light sprays of grey primer and light sanding. Keep after this, your build is looking good!

Cheers, Thompson

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I have spent a lot of time on this since the last update although there isn’t really that much to show for it. 

First I had to trim off the excess fibreglass which is straightforward but you have to be very careful as you can easily end up with splinters.  I found out the hard way.

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Next I had to make the bow which is a separate piece of balsa glued on rather than fibreglassed.  I think I mentioned previously but this it acts like a bumper, so if you hit something it won’t damage another boat or crack your own hull, the bow may break off but the boat will be watertight, just slower.  This meant cutting some rough triangle shapes to glue together to get the thickness, then shaping with a knife and sandpaper to get the right look.  I managed to get close enough to NZL20’s shape to be happy, then glued it on.

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Then I had to fit a couple of pieces to make the stern, or is that transom?  Who knows.  Anyway, usually this would just be a single piece but because of the shape of mine it meant 2 pieces.  It was pretty straightforward as its made from 5mm balsa so it makes it easy to tidy up by sanding later.

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Next was the hull fairing, which is basically covering the whole thing in a filler compound and sanding it back to smooth out all the undulations.  I ended up using builders bog instead of fairing compound which was what the guy at the LHS said I could use, and since I had it and was struggling to find the fairing compound (well, would have had to wait a few days for it to arrive) I went ahead.  I put a fine layer over the whole hull in 9 stages as its easier to mix and work with a smaller amount of the bog.  I did some of this at night since the bog cures chemically, not with heat and messed up one segment by not putting enough of the hardener in.  This was because the light in my garage is awful which I’ve now remedied with a $30 LED worklamp.  Its brilliant, like daylight over my workbench and its actually easier to see imperfections under that light than during the day.  I had to scrape all that off as it was never going to cure and redo that part.

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It was rough to start with but sanded down relatively quickly to a pretty nice finish.  I was happy with how it turned out as it was a very thin layer which meant it didn’t add much weight to the boat.  I did a few touch up parts until it was about 90% and then used the primer filler which the book says to use.  The can said it would fill imperfections up to 1/16” deep but it doesn’t.  I put that on thick in about 4 coats and left it for a few days to dry.  I has given a really nice finish over most of the hull and shown up the spots that need more attention.  I have just spot filled these with more bog ready to sand later tonight, then will give it a final coat of the primer filler.  This should give me a hull that’s as close to perfect as I’m capable and be done.

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After sanding, ready for the next lot of filler in small spots

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This is only chapter 3 of 17 (almost) complete, although I’ve done half of the next chapter as well which is making the mould for the keel bulb.

 

 

 

 

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What an epic tale and the finished result will be a legacy for the family

Pity you are not in the UK I could have sent you used air gun pellets to melt down as they are lead.

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Only step 3 of 17!!!!!!! 

Patience of a saint you but it’s looking awesome now there’s some boat shape to it 🚤 

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On 11/20/2018 at 8:05 AM, Nobbi1977 said:

What an epic tale and the finished result will be a legacy for the family

Pity you are not in the UK I could have sent you used air gun pellets to melt down as they are lead.

I hope it turns out well enough for that and doesn't sink on first use!

That would have been great as man lead is expensive as you have to buy it made into something. Luckily a friend who no longer can dive gave me a 1.5kg weight the other day. Not sure how easy a big lump of lead will be to melt though.

8 hours ago, Jason1145 said:

Only step 3 of 17!!!!!!! 

Patience of a saint you but it’s looking awesome now there’s some boat shape to it 🚤 

This is surprisingly easier than say a body shell. If you mess up there is nothing that can't be undone or fixed. Anything can be reglued, bogged (bodged?!) and hidden by filler and paint! Get a decal wrong or a paint bleed and you are forever reminded of it, well I am since I don't know how to fix them

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Ok so a long overdue catch up of where the Racing Sparrow is at.  Part of this is because I was away for a month over summer (5 months ago now) but mostly because my laptop doesn't like TamiyaClub and I have to restart Firefox in safe mode to post anything.

Hull

The hull is getting close to finished now.  I need to fibreglass the deck then do a final tidy up which will require a little bit of filler, sanding, spray putty and finishing off with some wet 1200grit sandpaper for a super smooth finish.  This will be done at the end when the keel is attached.

 

The main work that’s been done on the hull is fitting the internal structure, radio gear and deck.

The internal structure allows you to fit the radio gear and provides places to anchor the rigging and support the deck.  It is all taken from the big plan and basically just means gluing bits of wood in the right places so everything fits in.  Generally you cut a bit big and then sand it to fit so everything is a nice snug fit.

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The radio gear is all fitted and works.  I ended up using Flysky FS-i6 tx/rx which works really well.  I don’t need any of the functions for this build, but it has been used successfully to make a tank which was a bit of fun.  I was going to use MG995 servos which are super cheap, but in the end bought a Savox 0230MG waterproof servo for the sail.  It currently has a Futaba S3003 for the rudder but I have ordered an Alturn AAS700 which is similar specs to the S3003 but its waterproof.

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I’m deviating from the plans for the deck because the plans use a piece of ply veneer for looks.  A sheet of this is $60, and I want a white deck which is in line with the Americas Cup boats.  I used a sheet of 1.6mm balsa and am tidying that up with filler before fibreglassing it.  Just a single layer will be plenty for this.  I’ve cut the hatches and tidied those up too so its getting close to finishing.  I also need to mark out all the spots where the deck fixings go.

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It currently has the hatches cut out properly and some filler on the line in the centre and the gunwales but it needs a little bit more done before fibreglassing the deck.  Then its a case of attaching the keel and then do a final once over with some filler and primer, and it'll be ready to paint.

 

 

Keel

The balsa bulb ended up pretty good.  I tried to measure it using how much water it would displace to get an idea of how much the bulb will weigh.  It was very rough but ended up working out ok, with a heavier than expected bulb.  Its much easier to file off some weight than add it.

The second attempt at the keel bulb was far more successful than the first.  I found the problem with the first was that I followed the instructions for the plaster of paris and it was too hard.  This meant I had to push it down into the corners of the box and it ended up with a pitted surface from my knuckles.  It was impossible for the 2 halves to seal properly, so the lead spread out through the mould.  This would have worked if I had more lead, as it did form part of a bulb, but obviously wasn’t ideal.

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The second mould was made with much wetter plaster of paris which meant the drying time was longer, but as it was wetter it poured in nicely and had a much smooth surface.  You have to make sure that they are absolutely dry before pouring molten lead in to them, any moisture can actually cause the plaster to crack or worse.

 

A friend wanted to help with the lead pouring so I happily obliged.  We tried the gas bbq first to melt it but it just wouldn’t get hot enough.  The charcoal bbq worked a treat though and easily got up to a high enough temperature to melt the lead.  The pouring worked surprisingly well too with none being spilt on hands or “safety jandals”.  I'm not sure if the video will work but thought I'd add it in.  Yes there were 3 kids running around when this was done, any beer you see is light beer (honest)

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It came out with a lot of flashing but that just broke off.  The bulb was about 1450g which was 15g overweight, so I used a hacksaw to roughly cut it down and a file to shape it into a nice torpedo shape.  Its shorter and fatter than I would have ideally made, but not complaints, I think it’ll work just fine.  Next was just some filler to fill in any imperfections and it was good to go.

20190311_091703 20190311_135504 20190416_201253 20190402_142706

 

The keel is made of a strip of aluminium 4mm x 20mm and 270mm long.  I screwed a piece of wood into the window frame in the garage to hang it from so I could line it up properly.  First attempt I had it perfectly vertical in both directions, but didn’t notice that I ended up about 1mm off the centreline of the bulb.  This probably wouldn’t have been fatal, but for the sake of 30 minutes with a Dremel I didn’t want to risk it.  I had to cut and grind the epoxy glue/filler out and start again.  The second attempt was a success, so the keel is close to done.  It needs the balsa/fibreglass sleeve to be epoxied onto it which I’ll do when I fibreglass the deck as I’ll have the epoxy mixed already.

20190418_121752(0) 20190418_121806

20190516_130147

 

20190424_084711

The last photo is showing how its off centre so that isn't the final version.

 

Its actually pretty close to finished.  If I could spend the time on it it would probably be about 2 weeks work (waiting for stuff to cure etc) but only about 10 hours max.  Making the rig will be fiddly, so my 10 hours might be optimistic, but it should be ready to try by summer...probably

 

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