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[si101]

Hi,

First post so be gentle please.  I’m building a part works HMS Hood but to get my sea legs working a bit I have decided to build a second simpler project to try out a few technics etc.  I picked up a magazine from Smiths on the weekend called Model Boat Warships (special Issue) and in there was a plan for a semi/stand-off scale ww2 destroyer titled HMS Temerity.  The ship itself is a generic ww2 destroyer design, the instructions are pretty good but it doesn't really list all the bits I’d need to build it.  Reading through the pages I have completed a list but I’m hoping some of you with more experience could fill in the gaps and also add detail to what I’d actually need.

• Motor – RE540 or Graupner speed 500/600 (27 turns)
• Fine pitch prop 35 or 40 mm diameter
• Prop tube – 6 inch
• Shaft – Matching tube with M4 thread for the prop
• Motor to shaft connector (maybe flexible?)
• Motor Mount Plastic
• Rudder Assembly RMA 3065
• Rudder Servo (unknown)
• Rudder Servo Linkage wire (1mm or 1.5 mm steel)
• ESC Controller?
• Batteries 3x2 pack of 6 rechargeable cells
• Wires
• Radio Controller?

I have the woods, general tools, glues etc already.  Also I’m aware there are simple boats and designs to build than warships but they don’t really light my fire so I’m pretty set on this one.

I know there’s a lot of options here but I’m looking for fairly cheap parts for a beginner to build a boat to sail so if you could let me know maybe part numbers and also if there’s anything I have missed please. 

Many Thanks


Si

[malcolmfrary]

The list looks OK, your big choice is the radio, a lot of the other stuff will follow naturally.  Since you are doing a Hood as well, you will probably need a few extra functions, so a radio with enough channels would be a good idea. These days, that is almost ant 2.4GHz set.  These often come with a matching receiver, its a good idea to make sure that you can get extras.  What little compatibility there is between systems is being judiciously eroded by the individual manufacturers as time goes on.
Standard servos are pretty much just that - standard.  The differences that matter are in the spline arrangements on the output shaft and the shape of the plug moulding.  The former is not usually a problem as they are normally supplied with enough arms.  The latter is not a real problem as the pin layout is universal now and modelers have knives to remove the offending bits of plastic.
ESC - any reputable make of marine brushed control with a BEC and capable of handling 15A.
A stock (cheap)540 will do the job, these can often be got with a mount included.
Battery - thats a very normal "racing" pack as described.  The bigger the mAH number, the longer your run time.
Most ESCs come with wire attached, the only bits needed are a couple of lengths to connect to the motor terminals.  If desperate to buy some, Halfords for auto wire.  Otherwise, wire recovered from a dead electrical appliance mains lead is good.
Coupler - the Huco type is commonly available, you get the bits separately so that you get ends to match your motor and the shaft, and a bendy middle bit.  There are plenty of other suppliers of probably better ones, though.

[Tug-Kenny RIP]

Hello and welcome to mayhem Si.   

My,  you are making a good start. We all watch with interest and will follow your build.  Feel free to post any pictures  (we love pictures)  and ask any questions you like.  Have a read through the blogs about your particular taste and gather all the info you require.

have fun

ken

[si101]

Thanks Malcolm, Ken,


From the list and your pointer Malcolm I have come up with the following shopping list, could you have a look and see if there is anything that stands out as maybe over priced or could be done cheaper but still as a reasonable quality?  One question on the prop, how do I know if I want a left hand or right hand one?



Turnigy 9X 9Ch Transmitter w/ Module & 8ch Receiver (Mode 2) (v2 Firmware) - £36.59
Turnigy 9X 2.4GHz 8Ch Receiver (V2) - £5.48 (x3?)


Sun 540 Motor - Ref: 2134 - £6.78
6v 3 pole. Operating range: 6-12v, Free load drain: 0.7A @ 6v. Speed: 8,900RPM @ 6v


Motor Mounts - Ref: 2120  - 500 - 600 Mount £2.40
Aluminum Motor mounts for various sizes of electric motor


ESC - Mtronik Tio Marine15 - £25.99
The tio Marine15 is a new Brushed Speed Control designed specifically for use in RC boats that allows for the use of Lipo battery packs as well as the usual NiCAD/NiMH/Lead Acid that are more commonly used.
The Marine15 has a 15Amp motor limit, what this means is that you can use any, DC Brushed motor, as long as the current drawn by that motor does not exceed 15Amps under load (with the prop connected, under water).
A break down of the tio Marine15 specification can be seen below


NEW built in failsafe to protect against complete loss of signal or when out of range (compatible with all manufacturers receivers)
ABSOLUTE short circuit and motor overload protection
15Amp motor limit
1.2A BEC
5 -10 cells NiCad/NiMH input voltage (6.0-12.0V)
2 - 3 cells Lipo input volyage (7.4-11.1V)
Waterproof
Dimensions : L39.0mm x W34.0mm x H13.0mm
Weight : 55g


Battery: 6.0v 5000mAh Ni-MH Rx Pk Flat
Price:£30.00 (Including VAT at 20%)


Charger: Pro-Peak AC/DC Delta 3(2/3.5/5A)Chg
Price:£26.08 (Including VAT at 20%)
This Delta peak quick charger can be run from mains or DC. Its small size make it a very convenient piece of equipment to have! Some specs below
* Double AC/DC input
* AC : Charges 4-8 cells @ (2/3.5/5A)! * DC : Charges 4-7 cells @


Couplings:


Insert 1/8th Plain ( 3.17mm) Most 500 / 600 series motors
Price:£2.08 (Including VAT at 20%)


Raboesch Universal Joint
Price:£3.65 (Including VAT at 20%)


Insert 4mm (4ba) Threaded
Price:£2.08 (Including VAT at 20%)


Raboesch alan Key - Is this just a standard Alan key????
Price:£0.96 (Including VAT at 20%)


Shaft:  4mm Threaded Model Boat Shafts - 6inch - £11.09


Prop: How do I know if i need a left hand or a right hand????
40mm M4 Threaded 3 Blade R/H Brass A-Type Propeller - Pt - 146-13
Pitch 41.0mm
Price:£10.30 (Including VAT at 20%)


Rudder: Brass Rudder-Large +£4.99


Servo:
Futaba 148 Std Servo
One of the most popular general purpose servos. Its reputation is second to none. Ideal for use with cars, power boats, yachts, electric and engine powered aircraft and helicopters.
Specification
Weight: 44.4g
Voltage: 4.8v/6.0v
Dimensions:40.4 x 19.8 x 36mm
Torque: 3.0 Kg/cm (6.0v)
Speed: 0.22 sec/60° (6.0v)
Price:£11.99 (Including VAT at 20%)




So a GRAND total of about £150 - mmm, I must admit I was hoping for more like a hundred, maybe get a cheaper battery charger.


What do you think though, would that get my boat up and running???


Cheers - Si

[malcolmfrary]

Yes the gear will work, but do shop around a bit.  Have a look at Component shop, Howes of Oxford, Marks model Bits.  Shaving a few pounds off here and there will bring you nearer to your target figure. There are lower cost servos than the Futaba that work equally as effectively in a boat at much lower cost.
Unless you are determined to run on a LiPo, you dont need a Tio, the "ordinary" Marine Viper will do the job equally well.
Some of the items like the transmitter and the charger (dont stint on the charger, a good one will save a later fortune in batteries) will hopefully serve many years over hopefully many models, so thats a spread cost, even if its budget comes out of the same pocket as of now.  One thing to watch for on modern radios is whether they are full range or "park flyer" types, which are only intended for close range operation.
For a displacement boat, a 545 might be more appropriate, Same size and mount, usually the same price.
Coupler bits, OK - yes it is a standard allen key, one of what will probably wind up being a collection of that size as they get lost, replaced and subsequently found as they come out of hiding.
On a single screw boat, handing doesn't matter.  Terminology of handing varies between countries of origin anyway, some regarding rotation from the front of the boat looking back, others looking forward.  Just make sure it is properly locknutted on helped with a bit of threadlock.
Most of my rudders were home made from brass rod, balsa laminations, plastic tube to match the rod and recovered bits from dead 13amp plugs, but commercial ones work well.  Check the sizes against your plans, a big one costs more and might need a considerable amount cutting away at both ends.  A small blade can be enlarged by sticking styrene sheet to it.
Over the years, I have noted that building a boat costs £100 plus £100 per foot length, as a rule of thumb.  Lots of bought-in extras will obviously up the cost, home fabrication and more modest detail can reduce it.
As Ken said, read through the blogs, but use the search facility on the site as well.  The browsing and reading will give lots of useful information

[si101]

Thanks again Malcolm. 


I got my prices wrong on the radio gear, they must have been american prices, the postage cost was massive so i just bit the bullet and ordered a Spektrum dx6i and a few OrangeRx 615X's.  Hopefully they'll do the job.  I'll look at the other gear tomorrow and order them.  I'll reuse the radio gear for other models I will build in the future so hopefully it's a good investment.

[si101]

Well, all bits have been ordered, fingers crossed i have the right bits and they go together.  One question though, do i need to put an on/off switch in the circuit?  If so what one do i need to buy, there's to many to choose from.


Started doing some wood today, made a space on the bench in the garage.

[radiojoe]

The ESC has a switch already wired to it and as the receiver is powered via the ESC there is no need for any other switches, unless you are using a separate battery for the receiver.

Joe

[si101]

Thanks Joe, anything else needed like a fuse anywhere in the circuit or anything else?

[radiojoe]

Some advocate fitting a fuse, some fit distribution panels with built in fuses, personally I never fit fuses and have never had a problem, it's really up to you, the way I see it whether it's a blown fuse or burnt out motor/ESC your boat is still dead in the water.

[Colin Bishop]

the way I see it whether it's a blown fuse or burnt out motor/ESC your boat is still dead in the water.

But a blown fuse is just a bit cheaper to replace than a burnt out ESC or motor....

[si101]

Yer, I think a fuse maybe in order, I'll swim after it for the price of a motor or ESC 

[radiojoe]

As I always say, each to there own 

[si101]

So I have cut out a few bits and glued some stuff together and it's starting to look kind of boat shaped.   

[lakesidebob]

Many apologies if you already know this...the motor and prop shaft must be in-line......don't run it like that...ssss.

[si101]

Many apologies if you already know this...the motor and prop shaft must be in-line......don't run it like that...ssss.

Thanks lakesidebob, I was going to line it up more but not completely in line.  I thought that having the universal joint would allow for the transference of power through an angle like that, is that not the case with models like this?


Many thanks and please keep on pointing out issue I have, I'd prefer to learn on here than have it sink on me first trip.

[lakesidebob]

I am a noob myself,Si.18 months.Don't take what i say as gospel,but if you pour over the forum,all say boat prop shaft angle,motor to shaft being in line, is most important.It will take 1-2 degs,but you don't want any more,causes loss of power and perhaps vibration,no doubt other things.I am still learning the mysterious world of motors,shafts,prop sizes myself.Great job your doing,love the shape of that boat.Good luck with the build.Very helpful bunch on here too.Bob.

[malcolmfrary]

Yes, a big angle like that is a no-no for anything rotating rapidly.  A single universal will cope with a modest angle provided that there is only one plane of misalignment - in this example, the one seen in the picture.  It wont cope with any other, the two shafts must align perfectly looking down.  Also, the lines through the centers of the two shafts must meet in the middle of the spider.  Anything else, there will be excessive movement on the splines causing early wear and tear.  A double coupler will cope better, but is longer if sticking with this design.
Now is the right time to get it right, before it is hidden.

[si101]

Thanks, I'll make some modifications and post a few more pics.  My concern is that the motor may end up to high and cause the boat to have balance issues?

[malcolmfrary]

Make sure that other heavy stuff like the battery is as low as possible.  A less steep prop angle would help this as well.  Using a commercial mount is convenient, but needs space, raising the center line of the motor.  My preference is normally to mount the motor in a cradle (block of wood each side, hold down with elastic bands over pegs in the wood, block the other end up to match) and then line up the shaft to that.  The very early stages of building are the best time to sort this.
Just what size is it?  I have a 85mm long Revell Snowberry which goes very nicely with a 385 providing the power, and that at rather less than the rated voltage.  I made the assumption that your original shopping list was based on build information that came with the plan, but that motor does look big in there.