Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Working Vessels => Topic started by: steve mahoney on April 08, 2016, 08:59:22 am
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At this time of year we are officially 7 weeks into Autumn but this year we’ve had a record breaking summer and the extended spell of great weather has distracted me from my latest project. It has started to cool down a little over the past week so I’ve spent a bit of time back at the bench.
I had decided to build a 1/50 model of the Karetai, a 1970s diesel harbour tug from Otago, here in New Zealand. It is 28.6m LOA and is quite nice looking boat. There are several very nice models of this tug around the country so I thought that I’d give it a go too. Not a motored version this time, just something to gather dust on the shelf. Any viewers from Otago feel free to offer any advice.
In 1974 the Otago Harbour Board ordered 2 identical tugs, designed by Eken & Doherty in Sydney and built by Sims in Dunedin, Otago. They are hydroconic hulls with twin ASD drives and have very clean lines and uncluttered deck/superstructure areas. My last build was a hard working ocean going tug that was cram packed full of equipment and this build has no winch and very little deck gear – yahoo!
The Rangi was built first and then the Karetai was delivered in 1976. They served Otago until being sold off to Australia a couple of years ago.
Although they were supposed to be identical, some design flaws were ironed out in the second build and there were some minor cosmetic differences. Apparently one engineer was a stickler for cleanliness and his boat was kept in showroom condition while the other had a slightly rougher life. Rangi had the design flaws and I’m betting that it also had the scruffy appearance. When I was young describing something as ‘a bit rangi’ was a very derogatory term for poorly made or maintained, shonky or shoddy. The first stages of my build were ‘a bit rangi’ too.
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The developers of the hydroconic hulls were very protective of their designs and didn’t let any hull drawings out of their control. Now days these type of hulls are all over the place but back then it was all new technology so not many hull plans are floating about.
I managed to find some reasonable drawings of the Karetai, drew up the hull and had the parts laser cut out of 3.6mm ply. Those were my first 2 mistakes.
The ply I used I had picked up on special a few years ago (can’t resist a bargain) and it is hopeless: too flexible, very coarse grained, splinters and split easily, and warps in the slightest sunlight.
The original drawings I had found were not accurate, probably on purpose so that no competitor could use them. It didn’t become apparent until I started sheathing the hull – some of the curves were very clunky and the hull just didn’t look right with bulges and bad angles. After a few days it also developed quite a warp/twist and it took some serious clamps and about 500ml of resin to straighten it out again.
Then the crappy ply really came into its own and the hull needed about 7-8 rounds of filler/sanding/undercoat/repeat to even start to get smooth enough. Quite satisfying going at it with 60 grit, things smooth out pretty quick then.
So much for saving a dollar on the ply! Unfortunately I still have 1/2 a full sheet of ply left so I’ll probably go through this all again sometime.
That’s when I realised that I must be making the Rangi instead of the Karetai so the subject was changed 2 weeks into the build.
I was too embarrassed to photograph the hull construction (it was sloppy workmanship) so in the next post I’ll jump ahead a couple of weeks to a slightly smoother, straighter, cleaner hull.
The first 2 images are Day 1 just before it all hit the fan.
Bottom image is stage 1 of the hull straightening, with half of the fibreglass bracing that went into it.
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After much filling and sanding I finally got the basic hull to a stage that I was happy with
Still plenty of imperfections on the hull finish but nothing a little more filler and some 800 grit won't sort out.Fitted the bulwarks and made a basic error at the stern. Had to re-fit the stern bulwark, there's plenty of filler in there but luckily the fender housing hides most of the mistake.
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Someone else with a laser cutter :-)) I'm liking the lines of this build from the start, also the minimising of waste material by cutting out the bulwark supports from the part of the deck to be cut away. I look forward to your next update.
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Thanks Brian. No I don't have a laser cutter. I could never swing that past the wife. The house would constantly smell of burnt ply.
There are several firms that provide a cutting service in my town and to get all of the hull and superstructure components cut out only costs about $50 (20 quid). Saves tons of time, super accurate and I get plenty of spares.
Managed to get a few solid afternoons at the bench over the last few days and have got the hull to 95% finished.
Cut out the scuppers, added the cap rail, fender housing, bracing on the bulwarks (not sure what they are called) and hawser holes (not sure what they are called either).
And yes, the forward bulwark braces are supposed to be further apart than the aft ones.
The ply template is the base for the superstructure.
Only a few blemished left to correct and then onto the wet & dry!
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Sometimes I think its a good thing not to own your own laser, I've found I spend more time at the computer designing stuff on Coreldraw than actually modelling!
Your build is coming on great and the finish you have got on that hull makes it look superb, look forward to the start of the superstructure.
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Managed to get the hull finished, undercoated, wet & dry polished as smooth as a baby's bum, and prepped for painting.Added some anodising plates although I guessed at their placement as the only photos i have seen of the boat out of the water are when it was being repainted and the plates had been removed.
Also added some details to the hull.
I had brass etched some fender tie loops. They are 2 separate pieces – the hull plate and an eye that slots into it and through the hull ply.
Worked out OK. I attached the bases for the bow and stern fender straps.
Don't worry about the rough finish inside the fender housing, it will be hidden by the rubber fender.
And scribed out the outline of the ASD hull section. The ASD plate has rounded corners in a square cut hole in the hull.
You'll never get to see these lines but at least I'll know that they are there.
Now ready for the paint job.
Over the years the 2 tugs have had several colour schemes. The hulls have always been mid blue and the superstructure white but the decks have been pale grey, pale blue, light blue and the same blue as the hull. The bulwarks have been white, hull blue, pale blue and light blue.
The funnels have been white, hull blue, dark blue and yellow.
Plenty of options to choose from. I'm tending towards pale blue decks and bulwarks (yes, that happened) and yellow stack.
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This next part – the ASD drives, was quite easy. I thought that I might have a try at 3D printing so I drew up the drives and tried to convert them into a 3D modelling program. That's harder than it sounds unless you're a tech savvy teenager. The initial 2D drawing was easy, knocked it out in Indesign in about 20 minutes. After much trial and tribulation battling with a 3D program (another battle lost in my continual struggle – man versus machine) I eventually sent it to a 3D specialist and he cranked it out in about 20 minutes.
Then off to Shapeways. For a test run I chose strong, white and flexible, hit 'print' and waited. Nothing turned up for 3 months, apparently it was lost in transit somewhere in Brussels. The help team at shape ways where very helpful and re-printed the file, however for some reason the file kept hitting a print error and failing and the final stages of printing. After a minor file adjustment and a change to polished, strong, white and flexible, the finished products arrived. 2 weeks from ordering to delivery in New Zealand – not bad. The finish is a bit rougher than I had anticipated and the material doesn't handle sanding too well. I've read that you can smooth out the material by washing it in acetone. Acetone will melt ABS pretty quickly so I'm not really game to try it on something expensive.
Getting the props printed at the same time was quite cost effective. Getting 2 brass props sent from Europe would have cost 4 times as much as the total cost of printing both drives and props.
Still, not bad for a first attempt, and nothing that can't be fixed with a few extra layers of paint.
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I hadn't been able to find any pictures of the ASD drives on the actual boats before I made them, and as is always the way, the day after the drives arrived from Shapeways someone sent me a great photo of the Karetai in dry dock, with the drives in full view. Damn! I had made my main shafts cylindrical while the real ones are much more elliptical and only have 2 fixing points. They are almost like small rudders or vanes in front of the drives.
But if I hadn't just told you no-one would ever know. I'm sticking with my cylindrical versions as I can't really afford or be bothered reprinting them. Better luck next time.
After a few coats of undercoat and some extra layers of top coat they look OK. The props even spin freely. I'm satisfied with the result and know how to improve next time.
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Nice job!! :-)) :-))
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Great work Steve, it looks great.
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They look fantastic with paint on. A bit rough looking in the raw plastic. I'd never thought of having them 3D printed, I might have to draw one up and give it a try myself, my next project has an azimuthing (360 degree turn) kort nozzle and prop. The fly in the ointment for me though is that it also has to retract into the hull.
She is coming on famously man, but I've just realised with those props/housings does this mean she is a static model?
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Thanks boys. Yes, Brian, this one is just for gathering dust. What have you got in mind for your ASD drives?
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Well it has two main drives in Korts at the stern. Two tunnel thrusters at the stern, two tunnel thrusters at the bow and then the retractable azimuth thruster used for station keeping. I'm hoping to get them all working along with a daughter boat launched from a 'garage' in the stern and a working ROV - I did say HOPING :}
I won't give the name away just yet as it was only launched last year and has only been on active service for 9 months. :-))
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In the end I decided to go for the mid blue decks and bulwarks. The OHB didn't use this scheme for long and it tends to camouflage the vents and deck equipment but that's how it is in several of the photos I have. So now the basic hull is completed and I can move on to the superstructure. The bow bull's eye isn't attached yet, just there for the photo. I'll leave the deck equipment and fendering till later and I always leave applying the hull markings and name until the very last thing – sort of signing it all off. Plenty to do before then.
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... a couple more.The flash has made the deck colour appear yellower than it is. The colour in the previous post is correct.The deck will have another few coats of clear satin once the deck equipment is installed.
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And finally, a question for any Otago boys out there. What are these?Is it a valve of some sort behind the door? The only photos I have all have the door open and obscuring whatever it is. And what is the safety valve/cut off towards the stern and what would the text around it say?
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Steve....the AFT lever system will be a fire damper...on the stern vertical face of the engine house casing will be a pair of louvers which allow external air to be drawn into the engine room for both combustion and ventilation
In the event of an engine room fire, the dampers are closed so to inhibit fresh air [oxygen] from fuelling the fire....you may find that the handle lever is cross pivoted athwart ship on one shaft so to be operated on either the port or stdb side
Words such as Air Damper - Open - Closed would be a good bet O0
Not really sure what the handle/lever behind the door is...would be specific to the vessel, however is certainly of questionable design >>:-( with respect to access when the door is open %% ............. Derek
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The quality going into this build is superb you are doing a grand job Steve.
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The one behind the door looks like it has a hose or cable leading down away from it. Unfortunately I couldn't clean the picture up enough when I enlarged it to see what it actually is. If you look closely there is a similar hose or cable at the front of the superstructure next to the hatches.
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Go to the source.....
"Good morning
The object behind the closed door is the shore power cable connection to the inlet supply on the cross alleyway at the top of the access way to the Engine room on the port side of the tug Karetai
On the Rangi and Karetai this was only on the port side of the vessel. The electrical meter was positioned on the port side of the E/R cross alleyway
The other small lever at the aft end indicated in red is the lever for remote shut off of the fuel supply valves from the daily service tank to the main engine and generators. This was a lever system connected to wire rope and through a pulley system to the trip block on the fuel supply valve. - There was a lever on each side of the vessel in this position. Ie – Port side shut off the Port Main Engine and on the starboard side similarly shut off the starboard Main Engine and Generator.
The writing is – Fuel shut off valves or Fuel Trips – Open and closed are indicated.
Hope this clears this up.
Regards
Hugh M
Hugh Marshall
Chief Pilot
Port Otago Limited, 15 Beach St, PO Box 8, Port Chalmers, New Zealand"
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You beauty, Hugh!
Thanks, Steve
Go the mighty Hurricanes!
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I'm sure I'll be asking Antipodes a lot more questions as I only have limited reference of the boats.
In the meantime I've been making slow progress. The hull is pretty much completed and I'm happy with the paint job, only a couple of minor touch-ups required.
Now onto the superstructure.
I had the basic form laser cut and in theory it should have slotted together smoothly and quickly. In fact it took ages and quite a bit of interior bracing. I used ply 50% thicker than probably needed and had had it cut with the grain running the wrong way – it's 3 ply so bends better one way than the other. Getting it to comply to the curves required lots of cross bracing to bend around. I think I ended up with as much glue on me as on the wood and some serious clamping action. Once constructed I was able to cut out some of the excess bracing.
Here are the basic carcasses.
I can never resist putting the pieces together to see what it will eventually look like.
Still plenty to do and it looks pretty rough at the moment but you get the idea.
... and yes, I will have to cut out a section of the wheelhouse ceiling to glaze the windows. I didn't think of that one beforehand – Doh!
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Had some time over the weekend and managed to give the build a good crack and added the lip to the top deck, some of the etched brass stairs, hand rails and deck plates/covers to the superstructure. Also cleaned up the surfaces and got a couple of layers of undercoat and filler applied.
At this stage I realised that the plans I had were not 'as built' and that the portholes were not in the same position port and starboard. A bit more filler and drilling new holes but I really should pay more attention to the reference photos.
Skinned the funnel carcass with styrene and added the exhaust vents. I couldn't get the 0.5mm styrene to bend smoothly to form the curved front section of the funnel so it is made up of 3 layers of 0.2mm styrene. Worked out OK and is very solid.
I had expected the guttering on the wheelhouse roof to be quite difficult but it went on really easily. Glad I decided to add it, could easily have left it off. The wonders of CA glue! Couldn't do without it.
Still a way to go but it's starting to look the part now and there seem to be fewer blemishes after each session.
One more round of filler/sanding/undercoat and it'll be about ready for a topcoat. Fingers crossed.
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Slow progress on the build at the moment. Making lots of fiddly little bits that seem to take ages. Spoke too soon about the easy installation of the guttering. Took most of a weekend to install the window frames. Made a real hash of it and had to start again several times. Took the best part of another day to make the 2 engine room vents. Got a box full of completed hatches, vents and doors.
[/size]I've assembled the funnel/mast and added the very small life raft rack and radar/running light brackets. Just about ready for last undercoat and topcoats.[/size]The roof is not installed yet as that needs to be painted the same blue as the deck. Too hard to mask up when attached to the funnel and wheelhouse.Also, the downpipes from the guttering won't go on until later.Trying to dodge making a decision about fitting out the interior.
Still need to make the lights, searchlights, radar and safety equipment.Only major bits left to make are the anchor windlass and railings. No idea what the anchor windlass looks like as every photo I have shows it covered with a tarpaulin so I'll have to decide whether to make a best guess or get some more research. The real boat now works out of Australia and the owners where quite helpful at the drawing up stage but I don't really want to hassle them anymore so might be a 'close enough' scenario.
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"covered with a tarpaulin"
There's your answer staring at you!! %% :-)) %)
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Tarpaulin is easy to make. Kitchen paper roll with pva glue brushed well in and then draped over your item, add creases and folds as you mould it to the shape so it looks natural. 24 hours to dry and set solid, then paint in your tarpaulin colour, green/blue or offwhite. If you want to rope it down, use sewing thread and a small needle along the edges.
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Teabags also make good canvas. Same treatment as the paper towel method.
Ian.
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I haven't updated the build recently as I pretty much lost steam on it. Started with a hiss and a roar and then work and other thing got in the way.I have been slowly and intermittently making little bits and pieces to go on the boat – and there always seems to be more on the list however I'm back on the job now.
First thing I managed to do was drop the bridge and break off the top of the mast – Doh! It had gone together really easily first time round but the repairs took ages and needed lots of tweaking.
I hadn't had any reference of the anchor windlass but Phil (Mermod) sent me a couple of images of another (Tasmanian) vessel in this class and using a bit of licence I came up with a reasonable looking windlass based on Phil's version.
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Also made a start on the railings.[/size]I made up a simple jig/template for the flying bridge railings – much easier getting the 3 rails to bend into the same radius this way.The other railings took a bit longer than anticipated but I don't mind the whole soldering/filing process so it was a quite relaxing couple of evenings.I've slowly been adding to the box of bits to go onto the boat. There is a completed boat in there somewhere. Only the lights (12), flying bridge console, life buoy brackets (4) and speakers (2) left to make – yahoo!From today there should be more coming out than going in.Started placing the various components in place. First the deck equipment, then the fenders, then starting on the superstructure. As usual there is a order that things need to be done and as usual I find that I either haven't made something or need to remake/repaint something and the whole process stops for awhile.Everything is waiting on the glazing at the moment, which is waiting on a paint touch-up.
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The fenders went on much easier than I had imagined.[/size]The fender rubber is a strip of foam rubber that I have had laying around for ages. That was stuck on with contact rubber adhesive. You only get one shot with that stuff so I was very careful when positioning the rubber. Worked out OK.The fender straps and turnbuckle straps are the thinnest brass rod I could find.The hull and deck are now just about finished. Added the fire-hose piping, engine room escape hatch, towing bow and capstan, and the anchor windlass and platform in the bow. The deck and its equipment are all the same colour so it all tends to blend in together, same with the turnbuckles on the fenders – hard to see any detail – I guess that works in my favourOnly things on the hull left to do are the tyres and I can't put them in place until the boat's name and hull markings go on and that is always the last thing I do in a build. Hopefully that won't be too far away.
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Slowly but surely making progress. [/size]Needed to touch up the paint in a few areas and was then able to start attaching items from the box of bits. Also repaired the damage to the mast – I'm taking a bit more care with it now – don't want to do that again.The tow hook came together surprisingly easily. Not functional so it's made from styrene.The engine room vents are waiting for their covers and the work floodlights will go onto the supports next to the vents. Just the deck lights, railings and a few more deck vents to add.Finished the nav lights yesterday and the binnacle this morning so more pieces to make. The end is in sight. Yahoo!
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:-))
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These next photos have shown up a few areas that need to be touched up but well into the home straight now. I've been attaching all of the pieces made earlier and it's coming together at last.
These photos show the superstructure all completed apart from the searchlight and lifebuoys and widow wipers.The hull still needs its tyres chained on.
And a display stand – forgot all about that!?
Should all be finished in a few days if work doesn't get in the way.
The loud speaker is bigger than the original but at a smaller size it was hard to tell what it was.
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When the real boats were in this colour scheme the Otago Harbour Board (OHB) had become Port Otago so the OHB logo was no longer used, however it is such a good logo and was originally on the boats in brass so I've re-instated it. Similar license with the fire hose – the real boats had black rubber hoses, I've used the woven type, which is strip styrene – and they do stretch the length of the deck.
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Same licence with the work lights – the real boat had wimpy little fluoros so I've upgraded them to beefy halogens.
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Awesome!
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Lots of words we could say Steve....how about superbly crisp sharp detail %)......
If you keep up like this & with a bit of practice we could make a 1/2 decent model builder of you one day {-)
Cannot wait to see the engine room.......Derek
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Thanks boys.
Finally got round to adding the last little bits and pieces – aerials, lifebuoys and put on tyre fenders. A few areas needed a little touch up with paint, and lastly... the names and hull markings were applied.
I'd forgotten to make a display stand so that took a few hours extra but now it is all finished and can start gathering dust. Yahoo
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A few more before it goes on the shelf...
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Wonderful sir! O0
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Awesome work :-)) :-))
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Thanks boys.
Next one is ready to go.
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Great model and equally great job. Well done!
Regards
Wilhelm
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Thanks Wilhelm.