I wanted a fairly simple boat so that I could install and test a brushless motor.

It is a long time since I have made anything in balsa, and the
the design of the mermaid appealed and once scaled up to 28"
seemed to be about the right size for the new motor.

I came across the Mermaid on the Keil Kraft Eezebilt website
I think that DodgyGeezer (who frequents this forum) is the
man responsible for all the work on the site - have a look at

http://modelboats.hobby-site.com/

He responded to a post I made to the other Mermaid Blog
(Toylanders) asking about the possibility of more build info
about the mermaid for his website.

What I shall try to do is post the info as I progress the
build here and then possibly it will be copied onto the
modelboats.hobby-site website.

richald

p.s. what is the best size for pictures uploaded to this
website - I haven't found any advice about this anywhere. ?

I used the pdfs from the http://modelboats.hobby-site.com/
website scaled to 200%, and printed out on a Canon inkjet printer
(each original A4 page expanded to 6 A4 pages - cue the sellotape!

The original kit used 3/32" Balsa - I simply doubled that up to 3/16" (5mm)

Pic 1 : A view of the hull base - I also cutout the centres of the two largest
hull formers to allow access to the rudder horn at the stern and allow
clearance around the propshaft and motor amidships

Pic 2 : On the underside I have added some simple triangular fillets to keep the keel
aligned at 90 degrees to the base and also to assist come time to put the
hull sheeting on.

Pic 3 : At the stern I have added a brace under the deck to help when I
come to glue the transom on.

The brushless motor is a HobbyKing No-Name special - 1000Kv 222watt
outrunner with a 30amp HobbyKing Car ESC - this is the ESC . . .
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11742
cost for motor and ESC about A£16.50 !

Pic 4 :The final photo shows the motor on a metal motor mount - which is
thermally connected to the motor coils so it hopefully should avoid
overheating and motor damage (fingers crossed smiley required here!)
I have made a wedge-shaped motor mount baseplate, which will allow the
motor to be slid backwards and forwards & raised & lowered easily
to get motorshaft and propshaft alignment 100% before glueing in.

I have ordered a 45mm long double jointed connector from SHG models
to connect the propshaft and motor - should avoid any minor
alignment problems (fingers crossed again!)

Richard

I am still waiting for the propshaft connector from SHG, so
I'm holding off sheeting the hull to give easy access to install
the motor and motor mount.

Decided to build the cabin in a combination of 1/32" (0.8mm)
ply and 1/16" (1.6mm) Balsa - Balsa for the roofs, ply for
the remainder.

The thin ply for the cabin 'walls' makes for a much more
realistic effect - see what you think.

Pic 1: Because the walls are very thin I fitted soft 5mm
fillets around the tops of each cabin to allow the roofs
to be glued on securely. BTW : all the glues used are
either thick or thin superglue.

Pic 2: the cabin fronts did cause a lot of head scratching
to get them to line up and 'look right'.

Pic 3: The boat is definitely coming together and looking good!

Pic 4: Cabin detail.

You might notice that the stern sections of the cabin walls
aren't fitted - I decided to split the very long panel where
the KielKraft instructions suggest 'cracking' the sheet at a
bend line - when you have doubled up the scale, the full panel
comes out at over 500mm! -I didn't have a long enough piece
of ply to cut then out full length!

More pictures coming soon!

A bit more work done .....

Pic 1: Roofs (Rooves?) on front and main cabin fitted

Pic 2: Long view of boat from side

Pic 3: Rear cabin sides fitted

Pic 4: Rear of cabin and stern

I took a flyer and glued the deck down to the hull
base - I still need to install the the motor and
propshaft but I think I can do that before doing
the hull sheeting - I also had a dry run on installing
and removing the rudder through the hole in the rear
hull former....

Dave M - I will post an update specifically to answer
your questions, plus any other constructional hints and
tips I can think of.

I would appreciate any info on using sanding sealer (like
I said in earlier post it is a long time since I built
anything in balsa - like 45-50 years ago - gulp!)

I did have in mind using polyester resin to toughen up
the balsa surfaces and edges possibly put on with a plastic
'scraper' (I'm guessing that it may be too thick to brush on)
I shall experiment with this!

Richard

Not a lot of progress on the build - still waiting for the
propshaft coupling and sanding sealer etc.

Pic 1: Rudder Linkage : standard rudder but with a sheet brass horn
soft soldered to a 3mm I.D. brass collar.

Pic 2: Standard size servo with aircraft type links at each
end of rudder pushrod - all from the spares box.

Pic 3: Small clip made from leftover etched brass sheet

Pic 4: When your super glue is running out, or is more
'soup' than 'super' this speeds up the build!

Pic 1: Transom on and sanded to shape ready for sheeting -

two items of note :
a) A medium cut metal file held flat against the deck sheet
doesn't rub off much material - but it does allow you to
produce a really tidy chamfered edge (on the transom in
this case)

b) if you double up the size and the thickness of the components
you will find that they need to be cut a little larger come time
to chamfer them where the side and bottom sheeting will attach.
I had to glue a few extra strips around the transom (you may
be able to see the two pieces of 1/16 balsa glued to its lower edge
The other troublesome component was the first former back from
the bow - Immediately under the deck.

Pic 2: Rear cabin roof now on.

Pic 3: The removable cabin is now secured to the hull with two M3 bolts
through the (ply) cabin floor to a reinforcing plate and captive nut soldered
to a brass plate on the underside of the deck (Pic 4)

Pics 1 and 2: Motor and Propshaft Coupler fitted
The ESC is mounted Immediately ahead of the motor
and the power switch (which works through the
ESC) is mounted under the edge of the deck.

The propshaft coupler is from Mobile Marine Models
in Lincolnshire - it is really intended for tug use and
as such the power is transmitted through two shear
pins (visible through the plastic tube)

Pic 3: Motor Mount Side View - The angle of the
'wedge' matches the angle of the propshaft - you
just need to slide the wedge backwards and forwards
to get the motor shaft into line with the propshaft

Pic 4: Propshaft epoxied in and receiver mounted.

Its hull sheeting next!

Pic 1: Sheeting almost complete - just the difficult bit to do . . .

Pic 2: Rudder, prop, and propshaft skeg.

Pic 3: Sheeted Bow - chine line is a bit 'freeform' at the moment
but I intend to attach a 2x2mm spray rail from bow to stern,
it should help to define the chine line around the bow & act
as a painting guide.

Pic 4: Full hull and cabin

The sanding sealer has arrived, so next big job is sealing, sanding, and
filling any dips in the hull. Still have't really settled on a colour scheme
yet current thinking is : bottom of hull black, white separator then gold
and dark blue up to the deck. Will probably cover deck in varnished
mahogany planking, finally cabin will be gloss white

Boat building's a bit like the weather at the moment, Wet and Dry!.

I am typing this in a haze of dust from freshly sanded balsa, filler & sanding sealer, etc. etc.

I have decided to put a layer of tissue on with the second coat of sanding sealer.

The paint has been bought for the main part of the hull - dark metallic blue. There
will be a couple of coats of white high-build primer before the final colour coats.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Been looking at wattmeters - anybody got experience of this one from 4-Max ?

http://www.4-max.co.uk/wattmeter-budget.htm, A£18 with p. & p. Picture nicked from their website

The thought was that it could be mounted (in a waterproof container) on a boat & display
watts, amps & volts in realtime - it also has a facility to show maximum amps & watts.
I think that reading the display may involve using binoculars from the water's edge
unless your eyesight is good!

OLDHSLS - thanks for your posts - BTW already getting some boatshed rash!
I'd forgotten how soft unprotected balsa can be.

Richard