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Author Topic: Two piece mast?  (Read 4740 times)

Mi Amigo

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Two piece mast?
« on: September 18, 2009, 12:56:27 PM »

Hi
 I have just started building a Graupner Norderney, I think I may have bitten off a bit more than I can chew, I hope someone can offer some advice.

I think this will probably be the first of many questions regarding this kit.

It has a wooden mast which comes in two parts which must be joined together, It has  a very accurately machined V splice just under two thirds of the length

The mast is 1060mm long 12.3mm dia, the Vsplice is only 40mm

The instructions don't mention anything at all about the join, the only reference being on the plan ' mast splice (cement)'

I am wondering if I should strengthen the splice with a couple of bands cut from brass tubing, or maybe even just replace the 2 part mast with a single piece of dowel as I am sure the only reason for the splice is because the full size mast wouldn't have fitted in the kit box.

Or maybe I shouldn't worry and just build it standard with no modification at all.

I've included a picture from the plan.
 
Translations are as follows:
30 foresail
31 gaff topsail
33 top mast
34 mast splice (cement)
35 drill 2 holes in gaff, cement halves of throad(99) in place
36 2 belaying station 1 (throad halliards winch) (111)

All the best
 Neil
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roycv

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Re: Two piece mast?
« Reply #1 on: September 18, 2009, 02:22:10 PM »

Ola mi amigo, I have a Norderney, which I did buy in an auction part made and there is no splice in the mast.  But I think that there is a shroud point at the join.  Maybe that is just my model.  It is quite an old kit perhaps 20+ years old?

Anyway I have recently rebuilt a Gracia  yacht kit also by Graupner and it has an identical type splice in the mast. I had to remake this joint so this is what I did.
 
Personally I would first find a dead straight piece  of angled aluminium, H section is best, of about a metre in length. Glue the joint as specified using an aliphatic resin glue, see model airplane shops, make sure all contact surfaces are wet with glue make the join and tape into the corner of the aluminium angle piece so that it cannot move and is dead straight.  Wipe off excess glue with damp rag.

When it is dry give it a couple of days, I would then make a tight fitting dowel of about 1 - 1.5 mm diameter and drill through the joint at right angles and glue the dowel in place I would think 2 dowels would be fine.  Here perhaps you should match the drill sizes you have to the dowel.  For the dowel use toothpicks, sand to fit if necessary.
When dry sand it and it will vanish into the wood.  This joint should now be as good as solid wood.

If I can pass on a tip that came from correspondence some years ago with Ken Impey for finishing the mast, try this.

Sand the mast nice and smooth.  Wet the mast surface and let it dry.  This will raise up any spikey bits of wood.

Sand using very fine sandpaper, and then varnish with diluted 50 /50 varnish to turps substitute.  Let it dry and  gently sand again. Do this twice or til satisfied.  Diluting the varnish will get it soaking into the wood.

Then use full strength varnish sparingly and let it dry.  This time use wet and dry about 600 grit lots of water.  Do this at least twice and when you have let the final coat dry make sure the mast is straight and put to one side while you are doing other things, for maybe a week so allowing the varnish to go hard.

Then the (no longer) secret bit.  Get some fine quality wire wool and get a good surface layer of polish on to the wire wool, , furniture polish or similar.  Then proceed to gently polish all of the mast just get into the top layer of varnish, leave it for an hour or two and then use a soft cloth do a final polish.  The result is a very hard surface that is incredibly smooth.
I do all my masts like that now.

You can use a satin finish varnish to avoid too much shine.  I recommend at least 7 or 8 coats of varnishing for a good finish.
You can do the other spars as well at the same time including bowsprit.

The fishing boat is a nice easy build, the above only takes about 10 minutes each session.

The instructions suggest that you cannot take to the water with all the sails set, well I do.  I can give you some guidance along the way if you wish, do not give up she looks really good on the water.

I have some thoughts on :- lead displacement, keel, mine is as per the plan, removable mast, rigging, motor and propeller choice and method of working the rudder.

best of luck with the build.
regards Roy
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tigertiger

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Re: Two piece mast?
« Reply #2 on: September 18, 2009, 02:34:30 PM »

Hi Amigo

From what I can see of the plan there will be no major stresses on the joint, as the main sail gaff rests on the joint itself so that pressure is bearing on the lower part of mast, and there is no leverage on the upper section.

I believe if you use some glues, like Resinmite (Cascamite) the join is stronger than the original wood.
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Mi Amigo

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Re: Two piece mast?
« Reply #3 on: September 19, 2009, 03:47:54 PM »

Hi Roy and Tiger
      thanks for the replies.
Yes it is an older kit, the person I bought it from said he'd had it for 25 years.

The longer part of the mast does have a bit of a bow in it, when rolled on a glass surface it has a gap of 5mm between the mast and the glass so it is a bit more than slightly bent.

I didn't realise that a perfectly straight mast was so important, I have just  supported the ends and weighted the centre to try to straighten it, I'll leave it like that for a couple of days.

I am happy to use the original mast if I can straighten it having listened to the advice from both of you, whether I use the original or buy a new mast I will definately follow your instructions to the letter Roy.

I would be very interested to hear any Ideas at all on the list you mentioned.. 'lead displacement, keel, removable mast, rigging, motor and propeller choice and method of working the rudder', especially method of working the rudder as I really don't like the setup on the plan, space is limited, I can't think of anything better, I'm all ears

My thoughts so far are to use a geared  5 pole 545 instead of a 400,
I'm considering increasing the depth of the keel by 20 to 30mm and using fibreglass sheet in place of the ABS.
I would like the mast to be removable if I can find a good way of doing it.
I would also like to make the hull more or less watertight with lexan lids inside the coamings, I don't think heat build up will be a problem as I won't be using the motor very often.

I would also very much like to see some pictures of your Norderney if you have any.

All the best
 Neil
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roycv

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Re: Two piece mast?
« Reply #4 on: September 20, 2009, 01:49:58 PM »

Hi amigo,  I can do as you say but think it might be boring for other members of the forum, perhaps I can do it via email unless others are interested.  It is an old kit so not many people will want to know.  I can answer all the points you make though.
Perhaps you could tell us where you are with the build?

Mast.
If you can wet, even soak, the wood of the mast at the bend first, you may get a better response to bending it straight again.  The mast should be straight as otherwise the ready made sails will not set correctly.  I think use of a hairdryer would speed things up.

Hi T.T. There are  stresses on the upper part of the mast as if you look carefully at the plan ( 101 and 107) you will see that the forestay is connected above this joint and has 2 jibs running from it.  It is not obvious unless you have the full plan though.

Also I made the topsail removable for a heavy blow and it makes a substantial difference when you take it off.

I will follow up with some pictures, which views do you want?
regards Roy
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tigertiger

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Re: Two piece mast?
« Reply #5 on: September 20, 2009, 01:57:15 PM »

Hi Roy

Pics are always of interest.  :-))
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Islander1951

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Re: Two piece mast?
« Reply #6 on: September 20, 2009, 04:56:23 PM »

Hi amigo,  I can do as you say but think it might be boring for other members of the forum, perhaps I can do it via email unless others are interested.  It is an old kit so not many people will want to know. 

I, for one ,am interested. And there are always other applications of an idea.
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Mi Amigo

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Re: Two piece mast?
« Reply #7 on: September 20, 2009, 09:28:55 PM »

Hi Roy
 I will PM you my email address, please do post pictures on the forum too though.

I am sure there must be other Graupner Norderney kits gathering dust, seeing some pictures of yours might help get some of them down from the loft, built and onto the water.

Any pictures would be nice Roy, any views or features, some pictures of it on the water fully rigged if you have any, anything would be good though.

I've had the kit about 2 months but i just started it last week, I'm still working on the ABS, I haven't touched any of the wood yet.

I've trimmed the hull, assembled and glued on the piece below the rudder, cut out and trimmed the rudder halves, assembled the keel box but not installed it in the hull yet, and that is about it.

Once I get the ABS stuff all done and out of the way I will build the stand, I need to decide whether to extend the keel or not first though as I might need to build it slightly higher if I do.

I checked the mast today, it's a bit straighter, I'll give it some more of the same treatment, it might take a week I don't want to bend it too far in case I over do it.

All the best
 Neil
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roycv

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Re: Two piece mast?
« Reply #8 on: September 21, 2009, 12:05:09 PM »

Hi Amigo, well first I bought my Nordeney in an auction part made, which did limit me a bit.
The fin box was already in place but I have had the keel as per the plan in shape fixed in place so I did not really need the keel box.

I made my own keel from a piece of lead flashing with thin ply cheeks.  The main ballast is in the hull and as low as possible.

As a fishing boat she does make a lot of lee way and I decided that she maintains her scale appearance with just the designed keel.
In subsequent sailing I have not regretted putting most of the ballast in the boat, she goes just as well, and needs about 4 inches of water to sail in.  She does manage to carry all sails with internal ballast.

If you look at the hull you can see that she is quite streamlined underneath and does not require much power from the electric motor to drive her.

I made a bigger rudder and she does need it with a bit of a blow, I will show you how I operate the rudder.
There is something I may do and that is to plank the deck, it will look so much better.

I will follow this up with more but I need to take some photos.

regards Roy
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tigertiger

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Re: Two piece mast?
« Reply #9 on: September 21, 2009, 01:04:36 PM »

What is her hull section like. It is hard to tell from the pics I can find.

But as a barge, if she has a reasonable length of flat bottom and square profile, this will resist heeling a lot. And so the need for external ballast can be a lot less, especially if she is ballasted low in the water.

I think there is a fear with some people that low in the water means that she will get the gunwhales underwater faster when a boat heels. But I think in many cases the resistance to heeling is increased to a point that counteracts this risk of swamping. And with good scuppers should be little problem.

I find the biggest problem I have when heeled over is broaching.
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roycv

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Re: Two piece mast?
« Reply #10 on: September 21, 2009, 06:05:07 PM »

Hi all, OK I have taken some piccys so here goes.
 I made wooden jaws for the booms as I did not like the wire jobs.  They have a wire loop with black beads threaded on and the wire superglued in.
On deck you can see the tube leading the jib sheet out its about 1cm. high.

There is a sort of false heel on deck of quarter circle section. This was made from several layers of ply glued together and then a centre point was found and a screw put through.  This was placed in an electric drill and turned with the aid of a file and then sandpaper.  When the right shape it was removed and a hole drilled / filed to give a close fit to the tube glued to the mast.  All this is to stop water swelling the wood and jamming the mast in place.

You can just see the brass tube protruding this is glued to the mast and goes to the end of the mast.  The end of the mast drops into an easy fit tube located in the hull.  The tube on the mast has vaseline smeared round to prevent water entry.

The gaff boom has an angled internal slope to fit angle of the mast and there is a round hook as an uplift.

more to follow.
Roy
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roycv

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Re: Two piece mast?
« Reply #11 on: September 21, 2009, 06:07:37 PM »

Hi the missing picture.
Roy
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roycv

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Re: Two piece mast?
« Reply #12 on: September 21, 2009, 06:10:20 PM »

Hi sorry can't get rid of second picture.
The yellow wire is the RC aerial which has an inline gold plated connector.  I cut my rx aerials short and put a plug on them and have permanent aerials i the model.
Roy
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roycv

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Re: Two piece mast?
« Reply #13 on: September 21, 2009, 06:18:02 PM »

HUll.  I have hopefully got 2 pictures here, one shows the rather elegant underwater section with the fixed keel.
The other has the rudder showing the extension and even this sometimes has a fight to turn the boat.
Not so easy to see is the propellor.  This is an 'X' prop so that it has a large pitch to give it less drag when sailing.
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roycv

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Re: Two piece mast?
« Reply #14 on: September 21, 2009, 06:26:17 PM »

Rudder control.

This one shows the non-stretch fishing cord which operates the rudder.  It runs on a separate tiller underneath as there was a sailor at the helm and the upper rudder would just rest in the figure's hand.
The cord goes into the wooden boxes on each side and is fed down using tubes to the rudder servo where there is a screw compensator used to get a firm fit.
There are pulleys, any will do these are small Graupner ones attached with a small screw into a fitted block.
There were many fittings missing from my model so I had to make do!
regards Roy
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Brooks

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Re: Two piece mast?
« Reply #15 on: September 22, 2009, 12:59:54 AM »

Leeway is a direct consequence of insufficient keel...been there done that :-). If you want to improve windward performance, then adding a fin to your hull will help. I make mine detachable, both for out-of-water looks and for ease of transport.

Scale, or even scale-like, rudders have a hard time turning a model boat. I'd double the area of your rudder with a clear plastic extention (I find that those bubble packs holding tools etc. make a great source of plastic). Your rudder, operating just aft of the propeller cutout, will be particularly inefficient, so will benefit from more area. Real sailing ships used to see this loss of rudder effectiveness due to the prop gap. Rudders like smooth waterflow, something hard to achieve with gaps and props just upstream. Power vessels' rudders only work because of the propwash. The fast water makes up for the gap - I see this every time I am maneuvering barges with my tug: If I chop power to slow the assemblage, a turn will stop unless I feed in periodic bursts of throttle.
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tigertiger

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Re: Two piece mast?
« Reply #16 on: September 22, 2009, 01:48:10 PM »

Nice pics Roy

Thanks for posting.
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roycv

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Re: Two piece mast?
« Reply #17 on: September 22, 2009, 03:34:40 PM »

Hi Brooks thanks for your input nice to here from someone so far away.
I accept all you say but decided to go along with the less than yacht performance as it was a fishing boat.  I do sometimes use the engine to tack a little quicker.

I have attached a picture of the finished article and a view into the engine compartment.

I used a 380 piggy backed to a Graupner open gear box reduction 1 : 2.  It is noisy but saves some space as the motor points back towards the stern.  To be honest I don't think you need reverse as it is impossible to stop the boat in a medium wind but might back you out of a bad situation closer to the shore.
 
To bring you in with no wind then all it needs is about 4 - 6 watts max.  i.e. 4 -  6 volts  @ 1 amp.

I run everything from 4 x  2 Ahr cells giving 4.8 volts including the sail winch.
This is an arm winch with a servo slower box between the sail servo and the rx.  This gives a nice steady pull without sudden jerks as most arm winches do.

Excuse the messy wiring around the sail winch but I do have a slight leek somewhere and so it gets disturbed rather more than I like, this is my only sailing boat that leeks!
I think it could easily be run on 2 channels by having the maximum out sail travel also bring in forward on the motor.  This would release a 4 ch set for something else.

The mast shrouds, and rigging, are thin multi strand wire with a nylon covering as found in fishing tackle shops.  This made off onto a hook with a small section length of tube to hide knot.  I should have mentioned before that the mast sits in a tube that has a spring at the bottom so that when the shrouds are attached they are under spring tension so that there is no need to fit bowsies.

 A spring at the bottom of the mast (6 -7 pounds compression) , as in this case where the forces are moderate, works well.  In another boat I have (Endeavour J class, with a bigger spring) the forces are much greater and the spring compresses with the wind at the stern and slackens the fore stay.  I have a mod for this but it is not fitted yet.
I have not taken the mast out for many years now as it fits into the car ready rigged quite easily.

If I were starting again I would not have an external keel as the internal ballast works well and I do dislike seeing for example a Thames barge being brought out of the water with an 12 inch keel extension.

I might try a much smaller propeller but not sure.

Hope this helps and best of luck with the build, happy to answer questions.
Roy
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roycv

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Re: Two piece mast?
« Reply #18 on: September 22, 2009, 03:42:06 PM »

Hi all, I knew I had forgotten something!  The fore sail, I do not have this attached to the sail servo. there is an adjustable line that goes through the clew hole at the foot of the sail and across to the other side of the boat.  There are 2 possible hook on points depending on wind strength.  The sail just flips across as the tack changes.  You can just make out the hook on points on the port side near the bow.

Regards Roy
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Mi Amigo

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Re: Two piece mast?
« Reply #19 on: September 23, 2009, 12:05:24 AM »

Thank you so much for the pictures Roy.

It's a lovely boat, You have made a great job of it with quite a few modifications.

Crikey, where do I start, so much information.

I'll take your advice, I won't extend the keel, I will make it standard size as per the plan, as you say it is not a racing yacht, I will just accept the way that it sails and enjoy it for what it is.

Something you mentioned that I never really considered before is the use of reverse to get me out of trouble if the need arises, I've already bought a Graupner 550 gearbox for it with the intention of using the slower speed higher torque 5 pole 545 motor in it, I may be able to use quite a coarse pitched prop as you say for reduced drag and to pull me out of trouble when necessary.
I was thinking of using 3 channels and using the 3rd channel as the throttle, controlled by a pot with a centre indent so I can easily find the motor off position.

I have a Hitec 3/12 turn drum sail winch, I do need to make my own 26.5mm diameter drum for it though, (if my calculations are correct), I  would like to have the sail control standard as per the plan.

I am keen to have a removable mast, I do have a young family, there will be times when there will not be room in the back of the car for a fully rigged boat and 2 kids, I really don't mind spending 10 minutes to rig it at the waterside, the kids will appreciate it too as they won't have to travel in the boot  ;D, your spring loaded mast idea is novel but what are bowsies?

Also are the wooden jaws you made for the booms common on full size boats?

If you do decide to plank yours would a card template of the deck be useful?

Seeing the pictures of yours has really spurred me on, thanks again Roy.

Neil
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roycv

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Re: Two piece mast?
« Reply #20 on: September 23, 2009, 10:35:05 AM »

Hi Amigo, I am sure the sail winch you have will be fine, I use them myself.  Make sure you have access for the odd tangle that might happen.  I separate the running lines of the winch from the hanging sheets to the sails with cardboard, ex-cornflakes packets.

When I bought my boat in auction and not viewed, there were no booms or fittings so I made them as per the odd picture of full size craft.  Fortunately as I unrolled the plans  the sails were in there as well!

Bowsies are the adjusters used to tension the shrouds or sail sheets, I am sure you will find them on your plans.

When you connect the control sheets to the main and jib boom just use a hook so that you always have the same setting.

If I do plank the deck I was proposing to use the printed pattern already on the deck.  I have just done this on my Gracia re-build and it looks good.

One of things I do is to make a simple hard board flat container that you can put the mast and sails in complete.  Just do an outline of the combined sails and mast and make a simple minimum thickness box with easy latching catches.  This means that the sails do not get damaged and can be stored safely and easily at home.

Have you made a boat stand yet?  Most boaters do this first as it is easier to work on the model that way.
When I take a yacht out, the sail box goes flat in the boot (make sure your box fits your car!) and the boat on its stand on top.

Let us see your progress please.
regards Roy

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