Author Topic: Imara /Perseverance new thread 2016  (Read 5993 times)

0 Members and 1 Guest are viewing this topic.

Toby

  • Site Supporter
  • Sr. Member
  • *
  • Posts: 367
Re: Imara /Perseverance new thread 2016
« Reply #15 on: December 28, 2016, 18:58:42 »
Here are the threaded inserts I have of which one ought to be suitable to use for  securing, in conjunction with a bolt, the rudder support.
Toby
« Last Edit: December 28, 2016, 20:18:29 by Toby »

Toby

  • Site Supporter
  • Sr. Member
  • *
  • Posts: 367
Re: Imara /Perseverance new thread 2016
« Reply #16 on: December 28, 2016, 19:00:42 »
Michael
Thank you for the link about props. I shall go and view it now. Something to sleep on and store in the grey cells no doubt.

Trust you had a Happy Christmas celebration.
Toby
« Last Edit: December 28, 2016, 19:09:42 by Toby »

Toby

  • Site Supporter
  • Sr. Member
  • *
  • Posts: 367
Re: Imara /Perseverance new thread 2016
« Reply #17 on: December 28, 2016, 19:08:12 »
I have these two motors.

What do members think of their suitability for this tug.

T


des

  • Sr. Member
  • ****
  • Posts: 391
Re: Imara /Perseverance new thread 2016
« Reply #18 on: December 28, 2016, 23:01:56 »
Hi Toby

I recently finished a Model Slipways AZIZ kit, with twin screws & rudders, and intended to have white metal skegs with bearings to support the bottom ends of the rudder posts.  I left them off the model as I couldn't get them lined up accurately.  Later I realised that if I had fitted them, then I would never be able to remove the rudders.  However I left the rudder posts long in case the rudders were unstable once I got it into the water - they didn't, and the boat responded well to the top-hung rudders.  I've subsequently removed the excess rudder post material.

I'm in the process of building another AZIZ kit - this time I got the bottom skegs & bearings in place, but I am not committed to leaving them there.

I suggest you look at as many photos as possible of your prototype boat - if it had skegs and bottom bearings, then put them on the model, provided that you are absolutely confident that you will never have to remove the rudders from the model - for any reason, ever!

Des.
« Last Edit: December 29, 2016, 02:58:04 by des »

NickelBelter

  • Jr. Member
  • **
  • Posts: 54
Re: Imara /Perseverance new thread 2016
« Reply #19 on: December 29, 2016, 01:10:46 »
You can make a serviceable rudder with a skeg - and you don't even need to make the skeg removeable.  On all my boats i use telescoping square tubing for the rudder spine.  The rudder shaft is a round brass tube with one size smaller square tube soldered in it, capped with the usual screw-lock collar and arm.  The shaft extends at least a half inch into the square tubing of the rudder spine.  I drill holes in the spine and solder in brass rod and construct the rudder blade out of a sandwich - wood core, the same thickness as the rods with cutouts for them, skinned with styrene.  To remove the rudder, i disconnect the control rod, pull the shaft straight up and then the rudder, held only by the bottom socket, flops to the side and can be taken out.

mike_victoriabc

  • Admiral Poster
  • ******
  • Posts: 1667
Re: Imara /Perseverance new thread 2016
« Reply #20 on: December 29, 2016, 07:34:32 »
Interesting project - just trying to set up 4 rudders on a small tug and going through a similar process. Lots of good information here.

Toby

  • Site Supporter
  • Sr. Member
  • *
  • Posts: 367
Re: Imara /Perseverance new thread 2016
« Reply #21 on: December 29, 2016, 07:53:34 »
Hello Mike

Yes it is a great place this forum.

There is a wealth of information.  Where confusion arises re props and rudders is the numbers.
Clearly one prop and one screw on centre line is straight forward in that LH or RH prop makes little difference and any pull caused by thrust is compensated by a slight adjustment of offset rudder for straight steering.

Then we have two props either side of a single rudder which will turn contrary wise to each other.  It would seem to me that most thrust against the skeg is achieved with inward rotation (top turning in) .

Then we have two props  behind two rudders with then different properties.

You say that you have four rudders. How many props? 
Which tug has for rudders?
I am wondering whether this subject be started as a whole new topic if not elsewhere on the forum.

des

  • Sr. Member
  • ****
  • Posts: 391
Re: Imara /Perseverance new thread 2016
« Reply #22 on: December 29, 2016, 13:36:44 »
Hi Toby

I served my apprenticeship in a shipbuilding yard, building tugs.  One of those tugs had 7 rudders, with only one screw - three rudders behind the screw, with the middle one on the centreline; and four rudders before the screw, with two on either side of the shaft centreline.  This gave the tug very good manouevrability both forward and astern, at a time before Schottel and Voith-Schneider systems were not widely in use.  I wouldn't like to try to model that!

Des

Toby

  • Site Supporter
  • Sr. Member
  • *
  • Posts: 367
Re: Imara /Perseverance new thread 2016
« Reply #23 on: December 29, 2016, 15:36:38 »
Des

That would be something in a model.  I wonder if anyone has built such a vessel! ?

Toby

  • Site Supporter
  • Sr. Member
  • *
  • Posts: 367
Re: Imara /Perseverance new thread 2016
« Reply #24 on: December 29, 2016, 20:26:37 »
I opted for the plain insert. I drilled the hole and tapped in the insert. A little super glue just around the rim.

Then inside the skeg I pured in some finishing resin and lead shot. This would seal in the insert and make the skeg watertight. Some holes had been drilled into the skeg presumably as a thought to fixing a-frames.  And so the resin and lead should seal those too making the hull watertight; well once I have added hawse pipes.
« Last Edit: January 14, 2017, 17:11:55 by Toby »

Toby

  • Site Supporter
  • Sr. Member
  • *
  • Posts: 367
Re: Imara /Perseverance new thread 2016
« Reply #25 on: December 30, 2016, 13:34:24 »
Re  the motors - it has been recommended to me that I should not use the aforementioned Dean's Marine motors, for the revs would be too high and perhaps the torque too low.

I have used the 12v motor shown in the photo in my single screw Danube V tug which has a 130mm prop. I thought two of these would certainly be OK in the much smaller Imara/Perseverance.  The motor is from a car radiator fan. Much cheaper to purchase  these than the 42 per motor of the T12 ones available from certain dealer.
« Last Edit: December 30, 2016, 18:54:32 by Toby »

Toby

  • Site Supporter
  • Sr. Member
  • *
  • Posts: 367
Re: Imara /Perseverance new thread 2016
« Reply #26 on: December 31, 2016, 11:24:33 »
Can anyone tell me if this kit was changed at some point, and if so, why it was changed and which is the accurate version?
I ask, for, on looking at the supplied fake decking, I noticed that it does not match the plan. Bollards are in different places as are the hawse pipes to state two points.  I have not looked at the rest of the deck yet, as I am working on the hawse pipes at the moment.

Surely, other builders of this model must have noticed the differences.
I have only placed the fake decking and the windlass in situ and clearly that supplied does not match the drawing.

Toby

Toby

  • Site Supporter
  • Sr. Member
  • *
  • Posts: 367
Re: Imara /Perseverance new thread 2016
« Reply #27 on: January 14, 2017, 05:49:15 »
I recently learned of the fact that there is a photo of Perseverance in an old book entitled, Channel Sweep. The book, compiled by Warlow, contains photos of ships in The Channel during the 1950s and 60s and apart from warships shows a number of tugs.

The photograph of Perseverance shows how it was in 1951. I t is a good photograph.  Interestingly quite different to Imara  and of some other early photos post 1932 when it became RN tug Perseverance.

Second-hand copies of this out -of- print book may be still be found. I acquired a copy yesterday at 2.60 incl. 

I note in the back of the book there is listed a volume entitled,  Fifty Years of Naval Tugs. I have just found a copy on ebay and have bought for 3 incl.






2tugboats

  • Moderator
  • Hero Member
  • *****
  • Posts: 607
  • Roughly 3/4 inch scale semi accurate
    • Two Tugboats
Re: Imara /Perseverance new thread 2016
« Reply #28 on: January 14, 2017, 14:00:46 »
Excellent finds of pictures and information, Toby. "50 Years of Navy Tugs"
caught my eye. At 3 pounds, your priceless buy was almost free. . .

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

  • Site Supporter
  • Sr. Member
  • *
  • Posts: 367
Re: Imara /Perseverance new thread 2016
« Reply #29 on: January 14, 2017, 14:44:32 »
Thank you Michael.

Happy new year to you!

I wonder if members would be willing to liaise and create a database,  excel file, which listed photos and in which books they could be found. Perhaps even include the photo as a HTML link. That way members would have access to all photos for their builds.

What do you think?
Toby
« Last Edit: January 14, 2017, 15:31:22 by Toby »