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[steve mahoney]

As you may have noticed, I like to make New Zealand tugs – old and new. This next one is also a New Zealand tug but it doesn’t actually exist – yet.

While I was photographing a potential project (the Christine Mary) at Thomson Towboats in Auckland, Lance Brown (Thomson’s owner) gave me some plans of a new boat that he has in mind.

It’s a small 8.4m pusher tug. Unusually it’s single screw but with twin rudders. The 240HP engine is reasonably powerful for a little 8.4m boat so it should be able to get up and move pretty quickly between tows. Lance knows a thing or two about tugs so he might be onto something.

I’ve always liked the Canadian fast tug Nellie Irene and the Bratt tugs so I’m going to jump the gun on Lance and build this one as if it is aluminium. A lot of local boats under 10m are aluminium and there are some very good local builders of sport/fishing boats. They are a good choice for saltwater – low maintenance, stronger than fibreglass, robust, and reasonably priced, if any boat can be called 'reasonably priced'.

I’m also going to have to give it a name, something Lance hasn’t got around to yet. Most tugs in NZ have Maori names so a couple of obvious options are:
Piha = a steel lance (also a beach in Auckland),
or Mauri = brown.

However I think it’s going to be Ikatere = fast fish, on account of its imagined speed. Ikatere is also the name of the God of Fishes, who is the father of all sea creatures.
Ika tere = fast fish, Ika rere = flying fish, i.e. a fish that can fly.

Not a Flying Fish (the local Black Wing Flying Fish, Hirundichthys rondeletii, or the Four-Winged Flying Fish, Cypselurus lineatus), both of which are known here as Maroro.I’ve had a few Maroro fly into the boat while fishing way out and you wouldn’t want to get hit by one. They can be up to 45cm long, weigh 2 kilos and can fly at 55kmh for about 200m. Pretty cool to see a school of them out of the water though.

[steve mahoney]

First step was to convert the plans to laser cutting templates and get them cut out of 1mm ply. Easy enough. 1mm for the skegs seems quite thin but it’s about right for scale. The wheelhouse components are 0.8mm which is very delicate.

Laser cutting the parts might seem extravagant to some of you, and an easy way out to others. It is the easy way – but the parts are much more accurate than I could get by hand, and it’s way quicker. I’ve had a jig/scroll saw in the past and there’s no way I could cut parts as fine as these. Drawing the parts takes a bit of computer time but I actually enjoy that part. Figuring it out and problem solving to get the bits to fit together properly can be complicated but very satisfying. It usually works out OK, I haven't had to re-cut many items so far. For things like tyres it's a godsend.

It’s not expensive either, I’m not working any more so every dollar counts. On a 600 x 600mm sheet of ply I cut all of the components for 7 models. All up cost including the ply: $125 or less than $18 per model. And these are NZ$ which are worth 70% of a real one.

Same for the photo etching and rub-downs, if I can gang up all of the elements for 3 or 4 models onto one sheet the costs are reasonable. I’d still never let my wife know what a model really costs to make – that would be a deal breaker. It even makes my eyes water just thinking about the costs, Styrene, brass, paints, tools and things like propellors are double what they cost in the UK or US. The freight cost to NZ is a killer.

The rudder heels on this one are very delicate and I have a bad history of breaking them on other builds so I made sure to reinforce them with styrene before they got any handling. Then the hull frames went together fairly easily. It’s stronger than it looks, especially when the deck is glued in place. I didn’t need too much bracing as the twin skegs line everything up and hold it all in place nice and square.

[steve mahoney]

OK, the deck’s on and the stern quarters were packed out with balsa blocks and sanded to shape so that the side and stern panels could be glued on. The hull plates went together without any drama and everything got a coat of light sealer/primer to highlight any areas for filling or sanding.

Surprisingly little filler required and minimal sanding this time – I’ll take that as progress – and a win. Using paper, then thin card patterns to get the correct panel shapes is worth the extra effort.

This hull is quite different to the conventional hulls I usually make but it's starting to look like a boat. "It's a hull Jim but not as we know it".

The hull is only 1mm ply but with all those internal frames it is very strong.

Next time I’ll have to remember to run a few stringers – I totally forgot about it until after the first panels had been glued on. Got a bit carried away with my own success, but – so far so good, and I haven’t snapped off any rudder heels yet. Touch wood. I'm pretty happy with the shape so far.

[steve mahoney]

With any build I never know exactly what the building order will be. Sometimes I need to jump ahead and get something done before everything starts to fit into a more logical sequence. This time it was the fender rail. I would normally make the railings towards the end of a build because railings are so fragile. This boat only has a low rail for fender ties, however, the rail locks in the bow samson posts, which lock in the bow gunwales, which lock in the push knees. So the rail gets made now, it’s also trickier than it looks at first glance. The real rail posts are 100mm high x 100mm wide x 10mm thick with a 40mm tubing rail. And there are no breaks in the rail from bow to bow so I need to bend it quite precisely to sit in place.

It would have been simpler to make the whole thing as 40mm tubing but this is a training exercise so I’ll make it as per specs.

I have a lot of spare PE brass stanchions about the right width and thickness. They also have tabs to slot into the deck. I cut some down, glued them in place and filed them to down the correct height. They are tiny.

With a lot of spacers and tape holding everything in place I could then solder the rail in position – while holding my breath for most of the time. Centering the rail on the posts was quite tricky – tweezers in one hand , soldering iron in the other, really needed a third hand at times.

Filing the joins clean was fussy work as there isn’t much space between the rail and the deck – less than 2mm – not much more than my thinnest file. The whole thing took a lot longer than planned – all afternoon and then some, but eventually it turned out OK. It’s as solid as a rock.

Everything will be painted ‘aluminium’ so no complicated masking will be required for spraying.

[steve mahoney]

Back to the build...
With the fender rail in place I could then start on the push knees and forward gunwales.
The knees are styrene U channel, and the samson posts are styrene tubing with a brass rod core that slots into the deck. They need to be solid as the bow gunwales attach to them.
The rubber padding will be added to the knees after final painting.
The gunwales got a capping rail and some bracing. The samson posts got their cleats.
The plate on the deck is to hold the superstructure in place.

[steve mahoney]

Next: The propellor shaft housing, struts and rudders. The shaft was simple, quick and easy. The single shaft strut looks weird, but – hey! that’s how it is on the drawings.

The struts are styrene with a brass rod spine. The rudder footing is locked in place with brass rod pins. It all looks simpler and easier than it was.

Since this is an ‘aluminium’ hull it has had some strakes added to the base plate and one to the middle chine panel. On a real boat these strengthen and stiffen the hull and also help with lift to get the hull up and planing. In retrospect these may be a little over sized. If you can show me a photo of the real boat proving otherwise I'll happily alter them.

Quite happy with the hull so far. It’s all primed, undercoated and had a good go with wet&dry 400/800/1200 – smooth as silk.

Now I need to make the rudders. That’s for tomorrow.

[steve mahoney]

I usually base my models on real boats and spend quite a bit of time researching the boats and getting as many reference photos as possible. I try to keep them as close to the real thing as I can – you can get away with just too much fanciful stuff with freelance subjects.

The drawings I have for this boat are concepts only and don’t have much/any detail on the rudders so I decided to install Schilling type rudders.

Why not?

[Trucker]

All coming together very nicely mate, rudders look just the job, ive also had to do some research for the same type of rudders for my work boat thats currently under construction, a few attempts at making them though before i settled on the right method to build them, thats the fun of the build though..


Trucker

[steve mahoney]

Thanks Trucker, I only had to make 3 rudders before I got 2 good ones. That's pretty good going for me, I usually make and remake enough things to make 2 boats. Not so bad with this next bit.

The drawings don’t show a side fender, only some tyres – 22 of them. On the drawings they have calculated the weight of the tyres at almost 900Kg – nearly a ton. That’s a lot of extra weight so I’m giving it a lighter, chunky rubber rubbing strip upgrade.

Why not, indeed?!

The fender/rubbing strip is made out of sections of Basswood cut to fit the curve of the hull, with L profile styrene for the housing channels. That was an enjoyable afternoon – Basswood is so good to work with. Cuts and sands so well.

Then I added some deck fittings: bollards, stern engine-room escape hatch, and bow chain locker. The small circular plate at the stern is access to the emergency steering.

Experimented with a top coat but it’s not quite right. Let’s see how it looks with a decent colour...

[steve mahoney]

As this is an ‘aluminium’ boat the colour was pretty straightforward – aluminium everywhere!

Marine grade aluminium alloy is darker than you might think, much darker than standard aluminium, even darker than stainless steel but not as dark as steel. It’s shinier than standard aluminium but not as shiny as stainless, and not very metallic looking. Metallic paints never look very convincing at 1/50.

I experimented with a few different paint colours: silvers, raw and polished aluminium, polished steel, all with varying amounts of white or pale grey to try and replicate the colour and finish of real aluminium.

I have a very old very, very battered airbrush – the cheapest on the market, but it works just fine. Getting metallic paint successfully through any airbrush is tricky – too thin and you get no opacity, need too many coats, and it ends up way too glossy – or it can run. Too thick and it splatters or dries as it sprays and goes quite granular. I like the paint mixture to be about as viscous as milk – full fat that is, not the 2% stuff.

It took a few trial runs. Eventually I got the ‘Goldilocks’ (or Aluminiumilox) mix – not too silver, not too grey, not too shiny, not too cheesy metallic – just right. I’m quite fussy about paint colour and finish so it took a bit longer than usual to get it right.

Worth the extra effort though. You could make the best model in the world and ruin it with a poor paint job. You only get one shot at it. No way I’d want to have to sand it back to primer again.
Aluminium boats don’t need zinc anodes but they do need anti-fouling if they never leave the water and I thought I’d stay away from bog standard red or black. This one is warm grey. The colours are working for me.

The hull is now 95% done except for a couple of minor paint touch ups, adding the rudders, propellor, push knee rubbers, 2 large tyre fenders, and sea chest grilles. It can now take a back seat while I get cracking on the superstructure. The deck fittings (bollard, bow fairlead, hatch handles, etc) can wait.

In hindsight I should’ve made the deck from chequer plate. Didn’t have any, didn’t think about. Hindsight is always 20/20 vision. We’ll never speak of this again.

[steve mahoney]

These bits are all 0.8mm ply and they are very fine/flimsy. Some of those windows sections are very delicate. Luckily I had a few spares. The cabin ceiling needs to be in place to keep everything true and secure. The console got some access panels and I’ll add some instruments and controls – maybe.

On a previous build I got carried away with the interior details only to realise that you couldn’t see any of it through the windows. I’ll keep this stuff fairly rudimetary

[steve mahoney]

The roof went together quite easily but won’t get attached until much later. The drawings don’t show anything but this will also need nav lights, a mast, aerial, horn, spot light, and deck lights.

[steve mahoney]

Not a lot of action on the forum lately, where is everybody?

On the drawings these rails are attached to the ventilators, and all the rails are at the same height (higher than I have them). In practise neither of these things wouldn’t work well. The ventilators need to be removable or at least turnable, and the engine room access hatch wouldn’t open properly with all the rails at the same height. It opens from the bow end. Modeller’s license.

[steve mahoney]

The vents are styrene tubing. I raided the spares box for some diamond mesh. It was originally something I made for an SDM MkI model a long time ago. Never throw anything out.

Mesh was for the SDM funnel vents. The SDM is RC with offset bow and aft ADS units – spins, crab-walks but hard to get to go in a straight line.

[steve mahoney]

... and with a coat of paint...

[PierreP]

  well done for this little tug

[steve mahoney]

Thanks Pierre, nice to know someone is watching.

]Next: the roof can get attached to the cabin. The rear grab rails and mast were fitted and the whole thing got a light coat of paint to touch up any blemishes. So far so good.

The mast is brass rod and strip.  Also added a fuel tank cap (brown) and water tank cap (blue) on either side of the engine-room housing.   

]The window rubbers are laser-cut 0.4mm ply, they overhang the window opening very slightly. Once in place the windows can be glazed – the ‘glass’ drops in behind the rubber from the inside. I’m always very careful with this as it’s so easy to mess this up and fog the windows. I experimented with several glues beforehand and had pretty good results with an airplane canopy glue. Expensive, but did the job well. Please don’t tell it’s just plain old PVA glue.

[derekwarner]

Steve...what is the significance of the blue & yellowish/orange lamps?................ Derek

[steve mahoney]

They are tank caps. blue = fresh water, brown = fuel (diesel).

[steve mahoney]

Now that the windows are in, the exhaust and wipers can go on.

The exhaust is styrene tubing and the heat shield is some very fine PE stainless steel that I have had sitting around for ages. I think I found it on a trip to Tokyo years ago. It's very good quality and won’t need any paint.

[Capt Podge]

That heat shield material is probably the nearest to the real thing I've ever seen - looks great!


Cheers,
Ray.

[steve mahoney]

Thanks Ray – I figure that if I never throw anything out I will eventually find a use for it.

Back to the final hull details.

Added sea chests to each side. Why not indeed? The grates were cut down from some spare PE grating. Also added a water oulet on either side. The hull is pretty much finished now so I can attach the propellor, rudders and knee rubbers. I’ll leave the bow tyre fenders off at the moment as they are likely to catch on something.

[Trucker]

Hi, Steve
i like your little tug model, its a nice build to follow, the paint job interests me, you seem to have nice even coverage which i struggle with using a blue and a iwata neon air brush, as i spray the finish appearance is quite blotchy , nice gloss look then some dull areas, have you changed the needle for better flow, im currently using a 0.35 as standard but now thinking of getting 0.5 thinking this would be the way to go.


Trucker

[steve mahoney]

Thanks Trucker,

Might not be your needle, could be the flow rate. I have mine at 60psi for large areas, undercoat and metallics, and 45 for fine work. Won't dry the paint in the air or give too much overspray.

I use the cheapest airbrush available ($20, or 10 quid, for the set: airbrush and a couple of bottles). Many, many years ago I had several Badgers, Aerographs and an Iwata for airbrush illustration work. All quite good but very expensive. All long gone. For model work now, which is mostly areas of flat colour, I use the budget options and the results are pretty much the same.

I also use a cheap compressor with a tank ($120: 40L, 2hp). Constant pressure, adjustable flow, and dry air. Just need to remember to bleed the tank every 6 months, only takes 5 minutes. The little desktop compressors or anything without a tank are hopeless – no grunt, and supply air in surges.

What type of paint are you using?
High end airbrushes are designed to use inks and dyes or very diluted gouache, and don't handle acrylics and enamels well. They are too thick for them and if you dilute them too much they will splatter or give a very uneven coverage. I only use Humbrol enamels as they have always been readily available, and are reliable. I've gotten good results by thinning the paint (thinners, not turps) to about the consistency of milk and really making sure it is mixed thoroughly. I put the paint down in several light coats to avoid runs or 'orange peel' spots. Getting the consistency right is crucial so I always take a bit of time getting this right.

I'm experimenting with acrylics: AK, Valejo, etc, and have tried and didn't like Tamiya (not really acrylic, and their thinners is a rip-off) but 99% of my paints are good old Humbrol enamels. Undercoat and thinners are whatever is cheapest at the hardware store.

Disassemble and clean after every session. I go through a lot of thinners. I sometimes soak the metal parts in thinners for an hour. And at only $20 I can replace the airbrush after about 5 years.

Good luck and just keep practising.

[Trucker]

Hi, Steve
Thanks for replying , i have decanted some rattle can blue, stuff that is used on cars, had some results in the past, but, you have to let it stand for a time to allow the gases to escape before putting it through the airbrush, can you tell me what docks you visit, only way back in my early days i use to run from tilbury docks london to australia and new zealand on container ships, LOL, back in the good days..


Trucker