Author Topic: 1970s Diesel Harbour Tug 'RANGI'  (Read 15797 times)

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sea monkey

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1970s Diesel Harbour Tug 'RANGI'
« on: April 07, 2016, 23:31:05 »
At this time of year we are officially half way through Autumn but this year weíve 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 Iíve spent a bit of time back at the bench.
I had decided to build a model of the Karetai, a 1970s diesel harbour tug from Otago, here in New Zealand. It is 28.6m LOA and is quite a nice looking boat. There are several very nice models of this tug around the country (especially one by Vanya & KiwiNZ on the forum) so I thought that Iíd give it a go too. Not a motored version this time, just something to gather dust on the shelf.
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 Ė 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.

sea monkey

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #1 on: April 07, 2016, 23:32:47 »
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 Iím betting that it also had the scruffy appearance. When I was young describing something as Ďa bit rangií was a very derogatory term for poorly made or maintained, shonky or shoddy. The first stages of my build were Ďa bit rangií too.
The developers of the hydroconic hulls were very protective of their designs and didnít let any hull drawing 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.


sea monkey

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #2 on: April 07, 2016, 23:36:39 »
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.
Below: Day 1 and everything is about to hit the fan.

sea monkey

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #3 on: April 07, 2016, 23:40:47 »
The ply I used I had picked up on special a few years ago (canít 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 didnít become apparent until I started sheathing the hull Ė some of the curves were very clunky and the hull just didnít 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 Iíll probably go through this all again sometime.
Thatís 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'm now making the Rangi.
I was too embarrassed to photograph the hull construction (it was sloppy workmanship) so in the next post Iíll jump ahead a couple of weeks to a slightly smoother, straighter, cleaner hull.
Below is stage 1 of the hull straightening, with half of the fibreglass bracing that went into it.

2tugboats

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #4 on: April 12, 2016, 11:52:13 »
I also know about running into poor plywood. Like you say, lots of wood filler.
Your pictures are gems for laying the keel and on, thank you for sharing and
keep it up Sea Monkey.

Michael
Yet another case of why men and women go down to the sea in ships. . .A pleasure to be here and smell the salt air. Thank you Tugboat Forum. . .Michael in Anacortes, Washington www.twotugboats.com

sea monkey

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #5 on: April 17, 2016, 00:21:40 »
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.

sea monkey

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #6 on: April 17, 2016, 00:35:22 »
A few more...
You can see some of the areas that need some more attention.

sea monkey

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #7 on: April 17, 2016, 00:38:24 »
I managed to make a major mistake on the stern and had to adjust the bulwarks. Luckily the fender housing hides most of the problem.

VANYA

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #8 on: April 17, 2016, 00:59:14 »
Steve,

Its only a hobby mate, not a race. At this rate you will have it complete but the end of May.

Must say it looks good, very good actually and that laser cutter has done a treat. Its premo work and after seeing the Seatow this one will be brilliant also.

What can we get to you to build next...

How about the Te Maru, the Japanese style tug from Timaru. That will be a challanging bow to shape. We have the drawings.

We were down at Dunedin Model Engineers on Saturday for their 80th birthday celebrations.Brilliant day.

Keep up the good work.

Hayden
VANYA

sea monkey

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #9 on: April 19, 2016, 13:04:06 »
Thanks Hayden. Finishing this one quickly would allow me to start another before the wife knows I've pulled a swifty.
I do have something from Timaru on my wish list. Aorangi, Aoraki or Te Maru, whatever I can get plans for. Aoraki is a powerful looking beast and Aorangi is classic 60s look. That Timaru green looks good on anything.
« Last Edit: April 19, 2016, 13:17:27 by sea monkey »

sea monkey

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #10 on: April 19, 2016, 13:15:31 »
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 and 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.

sea monkey

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #11 on: April 19, 2016, 13:16:47 »
Only a few blemished left to correct and then onto the wet & dry!

VANYA

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #12 on: April 19, 2016, 19:44:26 »
Hi Steve.
I think I can get the Aoraki drawing set. It is a chunky machine and plenty of modelling to offer for a good keen builder like yourself.

I have parts of the Aorangi drawing set but not keen to let them go as it is my ultimate bucket list build. There is actually one been stylised down at Otago Model Engineers from photos I think. They are after the colour match too.

Te Maru certainly would be different. Did we include a lines drawing with that bundle we sent up for your archive? Have photos also as now its all locked off and you cannot get near her for photos.

What is the length of the Rangi your building? 1/48th scale?

Hayden
VANYA

sea monkey

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #13 on: April 19, 2016, 21:35:23 »
At 1/50 it's 575mm long. That little bridge/wheelhouse makes it all appear smaller than it really is.
I've got 2 more contenders ready and waiting after the Rangi Ė the old YTL James O'Brien (ex Westport) and the Parahaki from Whangarei (a monster). I'd be keen on the Aoraki drawings if possible, I could slip that one in next spring. How approachable are Timaru Port regarding photos?Only got the pilot boat lines in the pack you sent up.
Steve

VANYA

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Re: 1970s Diesel Harbour Tug 'RANGI'
« Reply #14 on: April 19, 2016, 23:33:14 »
Steve.

My yacht club friend is a relief skipper on the Aoraki every somoften so I am sure I can get photos without going through the full induction/ worksafe/HSE rubbish that percolate through everything these days.

It is one vessel I have not examined in depth.Might be worth doing once for posterity just in case it gets sold off. Have the drydock photos from Lyttelton on last survey if thats any help.

Good that you are building a model collection of museum standard tugs and workboats.Impressive.
VANYA