Author Topic: Imara /Perseverance new thread 2016  (Read 5992 times)

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2tugboats

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Re: Imara /Perseverance new thread 2016
« Reply #30 on: January 17, 2017, 10:01:54 »
The data base of tugs and their photos sounds like a pretty neat feature
to help every tug builder glean ideas and proofs from. I don't have any
idea of how to build one but perhaps someone here on the Forum knows.

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

Toby

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Re: Imara /Perseverance new thread 2016
« Reply #31 on: January 19, 2017, 05:50:48 »
Photo of Perseverance 1951

Toby

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Re: Imara /Perseverance new thread 2016
« Reply #32 on: January 25, 2017, 10:25:56 »
I am wanting to know about wash ports!

In the attached photos it can be observed that in the photo of the kit the wash ports have a hinge on the face of the plate and in the photo of the full-size boat there appears to be no visible hinge.

Anyone know how wash ports generally work, lock or are operated?

Is the top usually rolled and a bar inserted to act as a hinge; the ends of of the bar then seated in an appropriate boss on the edge of the cut-out in the bulwark in order that it can operate rather like a one-way cat flap?

The wash port on the model seems to have a weight on the inside when on the full-size boat that is on the outer face of the plate and in-line just above the rubbing band.

Should the deck be flush with the lower edge of the cut-out for the wash port.

des

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Re: Imara /Perseverance new thread 2016
« Reply #33 on: January 25, 2017, 15:10:48 »
Wash ports, or freeing ports.  As an apprentice, I worked on the construction of around 40 tugs, of which probably 30 had simple, open ports.  Water could slosh in from the sea just as much as out from the deck.  Larger, ocean-going tugs more likely had swinging port flaps, whereas harbour tugs, working in more sheltered waters, tended to have the open ports.

Hinged ports were generally fabricated by using the section of steel that was cut out from the bulwark to form the port opening - the remaining section was not a close fit, as the cutting process consumed around 6 - 8 mm all round, but it was close enough to stop a lot of water coming aboard once fitted back into the opening.

A hinge was formed by welding a horizontal section of round bar across the inner flat of the flap, just above half-way up, and protruding each side by 100 mm or so;  these protrusions simply fitted into a short piece of pipe (loose fit) welded to the inner surfaces of the bulwark.  Nothing sophisticated like bearings or grease nipples.  With the hinge bar above the halfway point, the bottom was slightly heavier than the top, so the flap had a natural tendency to stay closed, but would swing open just far enough to let water flow outboard off the deck.  A stopper piece of flat bar, welded across the top of the flap would stop it from swinging open inboard, which would allow water to come aboard from the seas.

The advantages of this crude, but effective method of construction were that it was cheap to fabricate; very little additional material required, as the flap was made from steel that otherwise would have been scrap; no maintenance required until rust in the "hinge" caused complete seizure; and then easy and cheap to cut off the rusted pieces and re-weld new pieces on as required.

I never saw a hinged freeing port with top hinges as in your kit photo - I think the flap would be too heavy to allow free flow of water from the decks, especially once the hinges became tight from rust.  This is why you don't see any hinges on the photo of the actual boat - they are hidden inboard behind the flap.

Finally, yes the bottom of the opening is flush with the deck in order to allow the maximum free-flow of water off the deck outboard into the sea where it belongs.

Des.
« Last Edit: January 25, 2017, 15:15:11 by des »

2tugboats

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Re: Imara /Perseverance new thread 2016
« Reply #34 on: January 25, 2017, 16:22:38 »
Thank you Des. On the two ships I sailed as refrigeration engineer, the over-boards
from the processing of fish had one-way doors and they were constructed just like
you describe. When I was given the order to make them, the owners both said,
"What ever is the quickest and cheapest". I made the hinges using pipe and rod having
a sloppy fit to keep them working free in spite of rusting.

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

Toby

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Re: Imara /Perseverance new thread 2016
« Reply #35 on: January 25, 2017, 17:02:55 »
Hello Des
Good to hear from you!  Trust all is well with you down there.

What a marvellous reply.  I took one look at the kit pieces and then the photo of a model shown in Model Boats magazine and thought , um I have misgivings about this. Then as I have acquired a few photos i am noticing a few more things.  In one photo under Perseverance there appears to be no mast  mid-ships and then in another the second mast is about 3/4 the size of the main mast.

Thank you for taking the time to help me especially as it seems my suspicions and my thoughts as to how it ought to be appear to be correct.

Strangely,  there appears not tobe any photograph of the tug Imara.  I am waiting on the Royal Maritime Greenwich as to plans and photos of the rug under either name.


I shall go ahead and start preparing and correcting the wash ports and then that shall be the hull just about ready apart from adding riveting and riveted plates for the joins in the bulwarks pieces and perhaps adding angle iron about the bulwarks, planking and superstructure.  I presume that these areas would have angle iron riveted holding all to the deck. Any idea as to the size? 1"1"  or 2"2" perhaps.

Toby

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Re: Imara /Perseverance new thread 2016
« Reply #36 on: January 25, 2017, 17:11:05 »
Michael. ......you have been up to all sorts!  I am pleased with your response too for to me that in the kit did not make sense for to what would the hinge bits on the flaps be fastened. No the idea that crossed my mind and that which you have both confirmed seems logical and correct. I shall construct those in the morning and hopefully enjoy doing it in the knowledge that it is the correct way and can be supported by the photos of full-size boat.

Toby

des

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Re: Imara /Perseverance new thread 2016
« Reply #37 on: January 26, 2017, 01:59:29 »
Quote ...  I presume that these areas would have angle iron riveted holding all to the deck. Any idea as to the size? 1"1"  or 2"2" perhaps.

Sorry Toby - can't help you there.  I have no experience at all with riveted construction techniques.  Every boat I worked on was fully welded.

Des.

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Re: Imara /Perseverance new thread 2016
« Reply #38 on: January 31, 2017, 21:34:47 »
I have placed the superstructure on to the deck to check its  appearance,  but note that the rivet heads don't run vertical but run rather slope left to right.  If I were to add doors it would look odd with this misalignment of rivets to the true upright of the doors.
The superstructure is the correct height compared to drawing.  Although deck and superstructure slope I assume the riveting, door edges and windows will be in true vertical alignment.  What is the point of adding rivet detail to kit parts if it has to be removed by the modeler.

 The funnel is the similarly problematic in that the rivet detail is ruined whilst trying to clean up the funnel to rid it of unnecessary join lines left in the mould.

What have others done concerning these factors in order to correct them.

T

des

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Re: Imara /Perseverance new thread 2016
« Reply #39 on: January 31, 2017, 22:33:14 »
Yeah - annoying, isn't it.

I'm working on a kit model at the moment.  As I was marking out the hull to cut the openings for prop shafts, rudder posts and shaft supports I wondered why nothing seemed to work out.  I found that the skeg moulded onto the rear of the hull was not central, but was off-centre by 3mm.  I spent ages deciding whether to mount the running gear correctly and have it not look right, or make it look right but off-centre.  I finally decided to split the difference.  Cutting off the skeg and re-making it was not a viable option, but I considered it.

Then, marking out the forward section to mount the bow thruster  I found that the shape of the bow is not symmetrical - one side is visibly "finer" than the other.  And the vertical "centre" of the bow is not central - it's 5mm off the true centreline.  No fixes for that one - I'll just have to persevere with it.  (By the time I found this, I was too far gone with other work on the model to send it back to the manufacturer.  Besides which, the cost of freight from Australia back to England would have been to much to swallow.)

For your rivet detail, I'd remove them, and redo them myself.  That way you can put the rivet lines where you need them to accommodate doors, ladder recesses, etc.

Let us know what you end up doing.

Des.

Toby

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Re: Imara /Perseverance new thread 2016
« Reply #40 on: February 01, 2017, 13:49:44 »
Pictures.
« Last Edit: February 01, 2017, 13:52:14 by Toby »

Toby

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Re: Imara /Perseverance new thread 2016
« Reply #41 on: February 01, 2017, 13:55:44 »
What have other modellers done about this heavy lump of white metal which is supposed to sit in the top of the funnel. Do we want heavy weight up there making for top-heaviness?

Toby

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Re: Imara /Perseverance new thread 2016
« Reply #42 on: February 01, 2017, 16:48:21 »
Four pictures of Perseverance where one can see differences between the 30s outfitting and the 1950s outfitting.

Toby

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Re: Imara /Perseverance new thread 2016
« Reply #43 on: February 01, 2017, 16:59:53 »
.

Toby

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Re: Imara /Perseverance new thread 2016
« Reply #44 on: February 02, 2017, 01:18:01 »
Two photos from the 50s, one from the 40s and one from the 30s.
A number of changes can be seen to have taken place during this period as the photos reveal.

Some models include still include the container, at the stern, for the row and tyres yet it appears not once the tug was used by the Admiralty. The cowl vent on top of the access to below decks at the bow, changes height and then to a new type altogether.  There are extra pipes from heating stoves etc.  Only 4 wash ports. As discussed earlier in this thread are cogently hinged to those on the models seen.  Note the position of the other ports both for and aft  which seem to be at odds with models of Perseverance and Innards seen online. No fire buckets or housing advice engine room housing.  The doors on the fore superstructure do not have portholes and are wooden.  The doors on the stern superstructure are flat-topped and not arched-topped.  I am sure other eagle-eyed will spot other differences. One curious thing noted in one of the photos is the absence of the aft mast. I assume that as the tug, when photographed,   appears to bear no name either perhaps a tidy-up,  re-paint or essential repairs were in the process of being undertaken.
Toby