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Author Topic: Fire boat 39  (Read 9704 times)

Garabaldy

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Fire boat 39
« on: September 09, 2008, 11:02:14 PM »

Ok i started working on this tonight.  I have decided to do a proper build blog because all you guys can give me your input and keep me right!  This is my 2nd build and first scratch build.  Im looking forward to the planking.  I have a pile of 1.5mm x 5mm obechi planks, possibly i would have been better using 10mm wide planks but its too late now......

heres some info on the build;

The boat is 1016mm x 210mm wide.  Twin props, i intend to use 2 MFA torpedo 850s turning 3 blade brass props.  I will be using an action mixer too.  Of course because its a fireboat, there will be working fire monitors and lights to match.  Im still unddecided whether to use ply or plasticard to construct the superstructure.  Im familiar with plasticard but i find it warps very easily.  Does anyone else find this?

Heres all ive done so far, its not much but its a start!   Il start cutting wood tomorrow night.

Gary

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barriew

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Re: Fire boat 39
« Reply #1 on: September 10, 2008, 08:41:50 AM »

I use plastic card a lot and don't have problems with warping. You do have to use the appropriate thickness, and brace if necessary.

Barrie
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John W E

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Re: Fire boat 39
« Reply #2 on: September 10, 2008, 10:22:44 AM »

hi there Gary

It is looking good   O0   an old saying my friend 'Cross that bridge when we get to it' - regarding building the superstructure.   Get the hull right first and then you will find building the superstructure and what materials to use will naturally fall into place.

With regard to the planking material; I notice you have opted for 5mm wide - in actual fact this may be a bonus to you; meaning - you will have a slightly stronger hull, due to the fact that you have a greater gluing area on the edges.

Remember Gary to purchase for yourself a boat-load of plastic clamps - springy clamps or the curler clips the aluminium ones.  The reason for this, is, if you clamp them over the planks to keep them level between the frames.

2nd last thing, is more of a tip/suggestion - you may already have done this - it is difficult to tell on the photograph you have shown - go over your drawn pencil line with a black or blue biro - you will find this does not sink into the plywood so quickly and then fade away; leaving you to struggle to find out where the line is.

Is there any chance of you putting a pic of the Plan on the Forum here; so we can have a look at it?  KEEP THE GOOD WORK UP  O0 :)

Aye
john e
bluebird
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Garabaldy

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Re: Fire boat 39
« Reply #3 on: September 10, 2008, 12:53:17 PM »

Blluebird, thanks for reminding me about the clamps.  Thats one thing i dont have!  As funds are low at the moment im trying to be as resourcfull as possible so would this sort of thing be ok for clamps - http://www.istockphoto.com/file_thumbview_approve/1878182/2/istockphoto_1878182_stationary_clips.jpg providing they have a big enough 'bite'?  Im relieved to hear that about the planks width, they are tiny!

I shall get a picture of the plan up tonight, after i cut out my frames of course! O0

P.S. i know the picture is terrible and doesn't really show anything other than a sheet of plywood!  Sorry.
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barriew

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Re: Fire boat 39
« Reply #4 on: September 10, 2008, 12:59:30 PM »

Gary,

Do you have a 'Pound Shop' near? They usually have plastic clamps for sale at £1 for several. Much better, and probably cheaper than the ones you showed, although the larger of these could be used - the spring ones not the paper clips.

Barrie
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Garabaldy

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Re: Fire boat 39
« Reply #5 on: September 10, 2008, 01:09:12 PM »

unfortunatly i live in a pretty remote place and only get to go to the big city once a month or so but my work has thousnds of those clips i showed ::)

Although after hearing a pound shop has that sort of stuff i will deffinatly be taking a look the next time im there.

Thanks,

Gary
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John W E

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Re: Fire boat 39
« Reply #6 on: September 10, 2008, 01:53:00 PM »

hi there Gary

I am attaching 2 pics - the top one shows the variety of clips that I have - I have collected these over a period of time - from the Pound shops, paper shops, you name it...even from the hairdressers and, if you look on the far right- top row you will see the granny clips some of the hairdressers use - ....

the other pic - pin vice drill - you may have one of these already, but, if not - they are only 2-3 quid on ebay - with a selection of very small drills they are extremely useful.   The idea is, pre-drill the planks with the tiny small drill before you push the pin through - it prevents the plank from splitting when you are planking.

hope this helps.

aye
john e
bluebird
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Garabaldy

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Re: Fire boat 39
« Reply #7 on: September 10, 2008, 10:50:38 PM »

Ive been thinking long and hard about this build again.  I know at this stage when im cutting out the frames it would be easier to drill the necessary holes for the propellor shafts in the frames but because im having a little difficulty figuring out where they will be im wondering if in this case it would be easier to "cross the bridge" when the time comes around?  Anyway i havent got as far as cutting the wood yet anyway, only marked most of it out as the pictures will show.  Also i have a picture of the plan.  If anyone would like to see the full size picture of the plan as its far clearer than the resized one pm me.

I have marked out the areas in the frames to be removed which you can see in the pictures, I have left a frame thickness of 15mm all the way round and left it slightly thicker at the bottomo f the frame where the keel joins to the frame.  I am yet to go over this with pen as bluebird suggested earlier because  im watching instinct which is an amazing movie.  I still need to mark out the notches in the frame for the keel joint too but this can wait.  Oh and the keel thickness is 20mm.

now its beer time ;D

Thanks,

Gary



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Garabaldy

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Re: Fire boat 39
« Reply #8 on: September 10, 2008, 10:52:33 PM »



direct link to plan photo
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John W E

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Re: Fire boat 39
« Reply #9 on: September 11, 2008, 10:48:01 AM »

Hi there Gary

Right, to plot the position of propeller shafts on your frames – it is quite easy to do.  :D But, bloody difficult to explain  ;D  so….we shall take it in easy steps.

Stage 1 – we need to put your main plan on a table; then you need a good steel ruler, plastic ruler, nice sharp pencil and a pair of drawing compass’ (you know the ones – they are used for drawing circles with.)    So, the first thing we do is on the view of the side of the model; we will locate the propeller shafts and we draw a centre line through the very centre of the propeller shaft on the side view plan.   This centre line goes well inside your hull.    In other words, on your particular hull, the centre line should pass Frame I; when you have drawn that centre line in; we need to draw in the frame positions at right-angles to your keel.   These are drawn in as dotted lines in my scribble to help you.    These must be at right-angles to your keel.

Stage 2 - move over to the drawing which shows the frames, the ones you have traced off to produce the ribs.   On this drawing you will see the position of the propeller shaft which has already been marked with a cross and a dotted circle to represent the propeller (on the plan).   

You will see the distance between the centre of the cross and the centre of your frames – it is called the prop shaft centre line.   This centre line runs parallel to your keel, at a set distance and in fact it never varies (on this particular model).  So, now you have 2 dimensions – these 2 dimensions are equal on both sides of the frame, port and starboard.   Now you have 2 plotting points from which to work, one from our side view plan and one from our frame plan.

Take your first frame, where the prop shaft begins to enter the hull; this looks as though it is frame K on your model.  Take a dimension from the bottom of your keel to where K dissects the centre line of the prop shaft – on your side view model – with a pair of compasses.   You move over to where you have drawn rib K on your plywood, on the centre line of Rib K you mark this height – from the keel up over.   This marks the position of the height of where the prop shaft enters the hull – now what we need to plot is the distance from the centre line of the frame to your centre line of your prop shaft.  This dimension comes from your frame plan which is marked with the cross.   Mark this position on Rib K on the plywood.

Move on then to the next rib and do exactly the same on Rib J, same procedure mark your height from the keel and also mark your distance.   This produces what is called a ‘plot’ of where your propeller shaft will pass through your frames and this in turn will give you an indication of where to drill holes through your frames for the position of your prop shafts.

I hope you can understand my above description.    I am attaching a couple of scribbles – hey I hope you can understand them.    If not give a yell and will have another go at an explanation for ya.   Neee worries.

Aye
John e
Bluebird
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Garabaldy

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Re: Fire boat 39
« Reply #10 on: September 11, 2008, 01:08:29 PM »

Thanks bluebird that all makes perfect sense.

How did you determine that the shaft goes through frame I?  Im not disputing this, just interested in how to work this out for myself in the future.

Also what is your take on the size of hole to drill in the frames for the shaft?  Is it wise to make the hole slightly larger than it needs to be as an allowance when installing the shaft?   

Thanks,

Gary
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John W E

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Re: Fire boat 39
« Reply #11 on: September 11, 2008, 02:31:32 PM »

Gary hi there

to answer your question about the prop shaft length and how did I determine that it should come through Frame I, to be honest, I had to do some guesstomation work  O0  looking at your photograph and knowing that the model is 40'' long - I had to determine, the rough position where you would like to put the motors - it looks as though you may place them at the back of the midship section - roughly about 14-18 inches from the stern.   Therefore I picked a 12'' standard prop shaft to work with (for length) and based the calculations around that length of prop shaft.   

To answer your second question, normally I will cut or drill the holes for the prop shaft through the frames about 6-10 mm larger than the diameter of the prop tube.  This, as you say, allows for mis-alignment during building and soforth and also allows you to relign, with packing, the tubes.  When you are happy with them, I normally epoxy the prop tubes in place.

However, I only fit the tubes after I have planked and fibre glassed all of the hull. 

I know some people fit the tubes first - which I have done in the past and then plank - but, I found it very awkward to sand and fibre glass around the tubes without damaging them.

aye
john e
bluebird
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Garabaldy

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Re: Fire boat 39
« Reply #12 on: September 11, 2008, 11:49:39 PM »

Perfect, again O0

Plotted the points out.  It would appear the point where the shaft exits the hull is also where the frame meets the hull meaning when i cut the hole in the frame (its frame k by the way) it be nearer a notch than a hull.  I assume it will be easier to create this hull once the hull has been built and im installing the shafts.  The one thing which concerns me is when i am doing this i will probably strike the brass pins when drilling and make a real dogs dinner.  Will i be safe enough to just not use brass pins in the area to avoid this?

Thanks,

Gary
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John W E

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Re: Fire boat 39
« Reply #13 on: September 12, 2008, 10:58:09 AM »

Gary good morning there

when you refer to the hole for the prop shaft in K frame, is it very close to where the planking is going to be?

if it is, what I normally do in this case, rather than pin with brass pins in this area of the frame; as you suggest, just glue and clamp the planks there.

What you could do, is, instead of drilling say a 10mm hole in the frame K; drill a 6mm hole and use that hole as a pilot hole to open up when you are ready to put the prop shafts in.

Last but not least, forgot to mention - another great clamp source - clothes pegs - the springed ones plastic and wooden - but remember to put a bit of cellotape over the jaws of the wooden pegs to stop the glue from sticking to the peg.

aye

john e

bluebird

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Garabaldy

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Re: Fire boat 39
« Reply #14 on: September 16, 2008, 12:00:12 AM »

Hello,

Ive been hard at work!  Ive got all my frames keel etc cut out now as you can see from the pictures.

When i traced the keel i just used the side elevation on the plan and traced right up to deck level which i though was the most sensible thing to do.  Now when i dry fit all my frames to the keel it would appear the frames at the stern are too high.  (the same problem at the front woops sorry i  mean bow!)   You can see in the picture i have drawn on a couple of lines roughly where deck level should be?  Or have i done somthing wrong when i traced out the keel shape?  I also included a picture showing the frame nearest the stern against the line drawing to show its been copied exactly as per the drawing.

Other than that though, everythings going good (i think!)




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Garabaldy

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Re: Fire boat 39
« Reply #15 on: September 16, 2008, 08:21:45 AM »

I have been thinking about this again on the way to work,

Is it possible i have drawn the slots on the keel facing the wrong way?  All the frames nearest the bow i projected the line on the drawing on to the keel then proceeded to draw the slot "towards" the bow"  On the frames nearest the stern i did the same but drew the slots "towards" the stern.  If i did this the other way around and drew the frames nearest the stern towards the hull and vice versa this would been the 2 frames at the stern would be  "further down the hill" on the keel there for would sit lower and the same would be at the bow.  Im not sure if this is true as the hill isn't very steep at the stern and the frame would have to move quite far before i would see much height change.   :-\

Oh well, back to drinking coffee and pretending to work :angel:
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dougal99

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Re: Fire boat 39
« Reply #16 on: September 16, 2008, 01:12:18 PM »

A good start would be to check the height of the drawn frames with the height of the deck at each frame position on the side elevation on the plan. I have found that there are sometimes inaccuracies even on plans bought from plans libraries. At least you haven't started gluing yet.

HTH

Doug
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John W E

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Re: Fire boat 39
« Reply #17 on: September 17, 2008, 10:33:12 AM »

Hi there Gary

I think by your posting on another topic - that you may have sorted your problem out with regard to the height of the frames - so let's do a checklist  O0

you have cut all the notches in your frames to take the deck edge stringer - the stringer which runs around the top of your frames; level with your deck

you have secured all your frames to a building board; and they are all in the correct position

you hare fared all the frames in with a sanding block, meaning you have checked that no frames are higher or lower than the next one to it; and that they all run in line smoothly - so when you put a piece of planking strip over any frame, it sits on the edge squarely & that you are happy

You have added strips either side of the keel? between the frames, so that your first plank lies on it and gives more support........

all singing and dancing

happy building there mate

aye
john e
bluebird
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Garabaldy

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Re: Fire boat 39
« Reply #18 on: September 17, 2008, 01:22:00 PM »

after alot of head scratching and measuring i came to the conclusion the lines for the 2 rear frames were slightly too high, this combined with some other minor inaccuracies added up to about 8mm - so i chopped it off the top of the frame.  Sorted!

Notches cut, 1 question though, the string should be flush with the edge of the frame so that we can plank over it?

Im not sure qhat you mean about adding the strips either side of the keel, what should these strips be made from?

securing and fairing will be finished off tonight ;D
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John W E

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Re: Fire boat 39
« Reply #19 on: September 17, 2008, 01:28:44 PM »

Gary hi there

Your stringers should be flush, to enable you to plank over them; yes

The strips I referred to, which go either side of the keel - well, I normally make them from 1/4 square Obechi.   If you have a look on the Whaleback build thread; where I am actually fitting stringers onto the hull, you will see a photograph where I have added these pieces between the frames, either side of the keel.

I will do a scribble if you want one  O0   got a new printer/scanner so I need to go to HongKong and back to let me post the scribble to ya.

Aye
John e
bluebird
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John W E

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Re: Fire boat 39
« Reply #20 on: September 17, 2008, 02:19:36 PM »

hope this works Gary, I may have crashed Mayhem website trying to post this pic....with words added trying to be clever ya nar......it's been saying me jpg is nee good..... here goes....
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Garabaldy

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Re: Fire boat 39
« Reply #21 on: October 01, 2008, 06:08:09 PM »

ok the hulls planked.  Ive not made as good a job of it as i hoped i which is why i havent posted any pictures yet.  I just need to do alot of sanding and it should be ok.  I l post some pictures tonight.

My motors arrived today.  You may have seen elsewhere on the forum i opted for brushless.  I  got 2 tornado c3530 thumper 340watt 1100kv which will hopefully give me some flexibility with batteries etc....  I ordered 2 35amp sea king speed controllers from himodel too which should arrive over the next few days.  Im just looking wondering how to mount the motors now.  Is anyone aware of any problems using brass or any other metal to mount brushless motors?
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Garabaldy

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Re: Fire boat 39
« Reply #22 on: October 01, 2008, 11:36:10 PM »

some pictures of progress.   hopefully get a coat of resin on tomorrow

i have also included a photo of the motor.  1 problem i can see is the small circlip on the shaft which means a larger clearance hole is needed on the motor mount. 




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John W E

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Re: Fire boat 39
« Reply #23 on: October 02, 2008, 10:01:58 AM »

Gary hi there

You know what - I have had a good look at your hull and planking and for a person who has never planked a hull before - you have made a dam good job of it - SO NEVER PUT YOURSELF DOWN - ask your mam when you were born, before you walked did you complete the London Marathon .... I don't think so mate, you have made a better job of it than a bloke who sits and talks about it and does nowt.... keep up the good work

aye
john e

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Garabaldy

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Re: Fire boat 39
« Reply #24 on: October 02, 2008, 10:15:41 AM »

Cheers bluebird.  I have learned alot with this one.  laying the planks was really therapeutic!

Hardware is all ordered and on its way O0
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