Plank on frame – Sparrow

[Boiler BriParticipant @boilerbri]

Sparrow, 750.

At our Wednesday club – ROFWACS, we race four types of boats or should i say there are four categories which we hope the wind will show up and push our boats along in it.

One of the categories is for a boat up 31" long and to any design you may choose and sail plan to match.

I have a couple of boats for sailing and of course the Panache – which is very much still on my best building board, Note to self (get on with it).

Brian

[Boiler BriParticipant @boilerbri]

First attempt at a plank on frame

[Boiler BriParticipant @boilerbri]

Intro 2

The category is filled by many different models and some of them are very experimental – the skippers who take it seriously have some very sleek vessels with innovative design and parts. I sometimes look at them and wonder who will turn up with a torpedo with a fin and sail to match the speed of the Whitehead device one day?.

A couple of chaps have a sparrow and I like the look of them with their large sail area. I have a 5 minute handicap which suits my sailing skills (always at the back)! The Sparrows soon catch up and pass me like they are J class vessels passing a sailing dinghy. I have to practice more.

Searching the internet a couple of years ago i turned up the plan and saved it for future plans in modelling. My steam engines do not get to run as much as i would like and all the hassle that goes with them teased me into looking for a more suitable and equally entertaining hobby. So i looked around a found the ROFWACS on a Wednesday and that got me interested.

I believe that if someone puts the effort into designing, testing and finally getting the result they wanted then they should have some reward. Fortunately the chap who designed the Sparrow wrote a hand book to go with it and at a few quid is well worth it. For me anyway as i dont have much vision with looking at plans and interpreting them, the detail sometimes eludes me. So the hand book for me is well written and has daily work listed and is easy to follow. Its also loaded with pictures. Nice BIG pictures.

I don't think i will deviate from the original build unless i cannot find a product in the boat in the UK.

So, i have made a start, i marked out my building board with a different coloured fine point marker to the colour i had used on the JIF build. First mistake. The boat is made- assembled on a back bone made from 5mm x 25mm balsa. All the bulkheads are glued to this and then some of the detail parts added in between them.a balsa stripper which is very basic, but it functions well with a good blade in it.

[Boiler BriParticipant @boilerbri]

Intro 3

When this has been done, the back bone is clamped to the building board and a 5mm thick packing piece put under the back bone at the centre point. The other end of the back bone is then clamped down to the building board. This puts a negative curve in the deck, aesthetic appearance, special requirement, key design? Who knows but its in the manual so i have it in my build. The chaps at the lake have not done this, but their boats sail ok so i can not see it making any difference?

I have put pictures in my Sparrow picture folder rather than put them all here, i will probably add one or two as i progress.

I forgot to mention, i have never made a plank on hull boat before. Always sticking to chine hulls with ply skinning.

That's the introduction, now to go to the model shop and get some 1/16" balsa sheet to cut up into strips. In my youth i made

[Boiler BriParticipant @boilerbri]

My simple stripper, 38 odd years old and getting a new lease of life. we did not have a milling machine so it was all free hand cut on a drill press YIKES.

 

Edited By Brian Dickinson 1 on 19/12/2019 20:40:33

[Boiler BriParticipant @boilerbri]

PANK ON FRAME -/ really ??? 🤔

[harry smith 1Participant @harrysmith1]

Hi Brian

I've had a go at planking, but with 3mm Ikea wooden blind strips cut down to 4 and 6mm strips.

The wood bends and steams very well, also like a strong balsa.

One tip is start from the keel and work up to the deck because you can use small clamps between the frame for a better shape.

Second tip, before planking sit the deck on and mark out all frame on the under side.

Mask tape all these up and seal the deck underside.

It's one off my bucket list, a long with double diagonal veneer planking !!!

Harry Smith

[Ray Wood 3Participant @raywood3]

Hi Brian,

1/16" panking sounds awfully thin to me? If that's what the drawing shows it must be ok!

Not wanting to contradict Harry from down under, I'd also start from the deck level aswell and work towards the keel if you want pretty topsides.

Happy Christmas

Ray

[Tim RoweParticipant @timrowe83142]

Brian

Great to see you up and running and good advice from Ray.

I have built this hull but with some modifications so I feel justified in making it first as a plug to make a mould from. I want three identical hulls.

Bryn is not very accurate with his metric / imperial conversions and he says 1mm or 1/16" for the planking. 1/16" is actually 1.5 mm but either way it is very hard indeed to plank a single layer at 1/16. Edge alignment is very hit and miss plus you get no sanding allowance. Very thin planking also tends to go flat between the frames as I does not wrap very well. The frame spacing on Swallow is very wide so be careful.

I would never consider balsa planking in anything less than 2mm and would use 2.5 and 3mm where there is lots of shape. After sanding and fairing up you will lose a lot of this extra thickness and anyway in the case of boats, the weight is not relevant. Some of his other conversions are a bit open but not so critical on the larger dimensions.

You will probably find than the hollows in bulkhead B give you a very hollow waterline with the bow quite pinched in. It was in this area that I made most of my design changes to increase the buoyancy in the bow. Swallow has a big rig and this is likely to cause behavior akin to a submarine at times.!

Tim R

[Eddie LancasterParticipant @eddielancaster]

Hi. Tim,you are right about the pinched bows of the Sparrow and it does want to behave like a submarine running before a strong wind.

I built mine as per the plan and used a fairly hard balsa and got a well shapeed hull, it was the second boat that I built, the first was Varmint a DF65.

Regards.

Eddie.

[Boiler BriParticipant @boilerbri]

Right so all sound advice so far. I did wonder about the plank thickness. I think I will increase to 2mm and see how it goes. The instruction says plank from the deck up

Varmint was a fellow club members design.

Only contradiction is the comment about weight in a boat. All the chaps bang on about getting the hulls to be a light as possible with out compromising the strength. I am only a beginner but I would have thought the lighter the better, which I can contradict as they have to sit correctly in the water which is all about weight ?

I also thought that the wettted surface was best kept to a minimum? Large ships have the bulb on the lower bow each designed to keep the flow of water down the ship uniform and as low as possible to reduce drag?

Works do today so no playing in the workshop.

Brian

[Boiler BriParticipant @boilerbri]

Thank you to admin for correcting the title.

Brian

[Ray Wood 3Participant @raywood3]

Hi Brian,

Enjoy the work do 😀

Boat speed is mostly about hull length, so wetted area is less important, you don't need to worry about balance as it's a proven design, radio behind the fin keel low down should do the trick 😁

All hulls have an optimum speed, something to do with wave length, that's why destroyers & cats are good for 30 knots +

Tim knows the technical stuff 😉

Regards Ray

Edited By Ray Wood 2 on 20/12/2019 16:23:52

[Boiler BriParticipant @boilerbri]

So. Last night I had a quick bash at stripping the balsa sheet into planks. 3mm x 2mm.
I retired after about 4 attempts putting it down to not being in the mood. I was trying it all in the hands.
I will probably be better mounting the stripper in the vice and holding the sheet with two hands to do it. Watch this space. 🤔

Bri

[Boiler BriParticipant @boilerbri]

This evening i had another bash at splitting the sheets into planks. This time i clamped the splitter to the bench so i could use both hands to steady the sheet of balsa as i pushed it through the blade. Hey presto, I ran a full sheet off.

I did select the sheets carefully this time so the grain matches.

I temporarily pinned a strip in place to see how it bent and what it looked like. After a bit of thinking about it and how it looked i glued it in place and pinned all the joints. My grip is not good – on a good day i can crush a grape! Trying to squeeze the Gorrila glue was impossible. Has anyone a good idea for dispensing glue easily?

I managed but it took me both hands (glue is new not old). So one plank on and glued. Tomorrow i will do the opposite side and then start to work my way up- evenly.

I have put pictures in my files if your interested.

 

Brian

Edited By Brian Dickinson 1 on 03/01/2020 20:49:30

[Ray Wood 3Participant @raywood3]

Hi Brian,

Make life easier and cut your planks wider for the topsides, I use one of those disposable syringes for pva & gorilla glue it's more accurate and maybe better to dispense for you, I expect screws may stock them ??

Regards Ray

[Boiler BriParticipant @boilerbri]

Hi Ray.

That’s a good idea. The action of a syringe will be easier to work.
I have cut all my planks, so for this model I will use them but thank you for the suggestion.

Brian

[Boiler BriParticipant @boilerbri]

I tried the syringe method tonight. I only have a 5ml one but it works great. Thank you for for suggestion.

Brian

[Boiler BriParticipant @boilerbri]

The planking is coming along but it's a slow process.

I bet you could do a complete boat in a day if the glue set quicker

Having time to play as well would help

Brian

[Ray Wood 3Participant @raywood3]

Hi Brian,

Balsa cement, and it smells great 😀 dries fast, sands better than PVA.

I use the big UHU tubes.

Regards Ray

[Boiler BriParticipant @boilerbri]

Just to reassure Ray, we are still building and planning more boats. Covid has encouraged more building with me and having now not run some of my steam engines at the track for nearly 12 months i think a change is in hand.

I only managed to run my engine 3-4 times a year and looking at VFM i think its a bit on the low side. I have been sailing Yachts more than running the loco and i enjoy the simplicity of it, go sailing, go home charge batteries (if needed), drain any water out and leave to stand until next time. This is far simpler than the Loco. Its also lighter to manoeuvre.

As for building, the time i allow myself if far more productive on a boat build that engineering requires. I also have 6 grandchildren now and time is spent with them rather than in the workshop engineering. So maybe for me the future will see more boats.

I have been attaching more planks to the sparrow and soon that will be complete and ready for preparing for the glass cloth. I have to say that i have not found the planking easy but it is only the first time doing that method.

Brian

[Boiler BriParticipant @boilerbri]

Well you can always tell when the weather is rubbish and the days are getting shorter as we all start to look to our indoor pursuits and I am no exception to that.

For now i have put my locomotive and traction engine to one side. No one at the club is testing boilers and if we were no one is running steam.

So back to the Sparrow. I am by nature not a repetitive manufacturer and when i got half way up the sides of the boat with the planking i got bored and put the boat half way up to the roof on a shelf to gather dust. So now in the last few days i have taken it back in hand and pushed on with the planking. God you have to be a patient geezer to get it perfect, which is why my planking looks like it was shot at the boat from a few meters away. I am sure a bit of 120 grit will make it smooth, but to you fellows who make the joints 100% i take my hat off to you. I also have a Ray Wood secret weapon up my sleeve in the form of water based resin and glass cloth, plus some filler.

So by this time tomorrow i will have closed the keel and will be already for that 120g paper.

Now, at this junction anyone who has one of these will spot the mistake.

That's right, i have made the stern a bit shorter than it should be. The deck finishes where the planks end and the planks should go further back to allow a sloping section of the hull to be made.

Like this shown in this picture taken from the building manual:

I might see what it looks like when i take it off the building board, modern boats are all square at the back end – please do not quote me i could be wrong, again!

At the worst i can shape a balsa wood block – so now you can all say, measure twice cut once old man.

Any way progress and taking shape.

Brian

[Ray Wood 3Participant @raywood3]

Hi Bri,

Yes strange how the interest changes with the time of year ! The autumn is my railway time traditionally, used to be looking forward to the Midland show and I've been messing around with my branch line station in 00.

My best tip is if planking gets you down make them wider !! You may have to file flats on the bulkhead s to make them seat properly.

Looks like you need to wittle a balsa block for your stern, so she measures ok.

Regards Ray

[Boiler BriParticipant @boilerbri]

Cheers Ray,

I think i might upset the balance if i make it shorter?

Brian

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