Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1] 2 3 4   Go Down

Author Topic: Modern Harbour Tug  (Read 19642 times)

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Modern Harbour Tug
« on: January 22, 2010, 09:36:10 PM »

This is the latest addition to the Toesup fleet.. A modern harbour tug.. 24" x 11"

I have made up my own plug / mold / hull from a few sketches over the last 18 months or so..
I've also produced my own 'Z' drives...  O0

The tug has a working winch and will have working keel coolers, cooling the motors and ESC's
Logged

bosun

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 379
  • Location: NEWPORT SOUTH WALES
    • bosunsmodelboats.com
Re: Modern Harbour Tug
« Reply #1 on: January 23, 2010, 12:10:02 AM »

Thats a good looking boat Toes, have you any pics from the start of the build, nice one
Bosun
Logged
bosunsmodelboats.com

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #2 on: January 23, 2010, 12:39:21 AM »

Yeah... just a few..  O0

The plug..
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #3 on: January 23, 2010, 12:41:46 AM »

Still the plug...
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #4 on: January 23, 2010, 12:43:15 AM »

.. still the plug...

Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #5 on: January 23, 2010, 12:45:05 AM »

Plug and mold..
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #6 on: January 23, 2010, 12:46:43 AM »

Plug, mold and hull..
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #7 on: January 23, 2010, 12:48:06 AM »

The build...
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #8 on: January 23, 2010, 12:49:46 AM »

.. still the build..
Logged

gingyer

  • Full Mayhemer
  • *****
  • Online Online
  • Posts: 1,511
  • Location: Glasgow
Re: Modern Harbour Tug
« Reply #9 on: January 23, 2010, 01:00:54 AM »

any chance of seeing how you built the Z drives :-))
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #10 on: January 23, 2010, 01:06:26 AM »

The original sketch..

The keel coolers...
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #11 on: January 23, 2010, 01:08:24 AM »

any chance of seeing how you built the Z drives :-))

Of course...

The Z drives...
Logged

gingyer

  • Full Mayhemer
  • *****
  • Online Online
  • Posts: 1,511
  • Location: Glasgow
Re: Modern Harbour Tug
« Reply #12 on: January 23, 2010, 01:15:10 AM »

thanks it has given some thought to something
in the future  :-))
Logged

Bunkerbarge

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,359
  • Location: Halifax, UK
Re: Modern Harbour Tug
« Reply #13 on: January 23, 2010, 02:25:18 AM »

An absolute work of art Toes and a great build thread.  Lovely engineering throughout and a very unusual and interesting subject.
Logged
"Dirty British coaster with a salt-caked smoke stack, Butting through the Channel in the mad March days"

marinaru_ro

  • Guest
Re: Modern Harbour Tug
« Reply #14 on: January 23, 2010, 07:18:17 AM »

Great job on it Toes! I just love the Z-drives.
George
Logged

TugChief

  • Guest
Re: Modern Harbour Tug
« Reply #15 on: January 23, 2010, 04:12:58 PM »

Very interesting model, built in the style of a tractor tug but is actually an ASD!  I think that you will have a very interesting time when you tow over aft with her as the towing point is actually aft of the pivot point of the units..........will be very interesting to see the outcome!  A good looking model none the less.

TugChief.
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #16 on: January 23, 2010, 04:31:59 PM »

I think that you will have a very interesting time when you tow over aft with her as the towing point is actually aft of the pivot point of the units..........will be very interesting to see the outcome!


The winch unit is about 2" (50mm) in front of the Z drive units... and the 'staple' is only just behind the CL of the drive units..

"will be very interesting to see the outcome"... can you elaborate please?...  {:-{
Logged

Number 6

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,276
Re: Modern Harbour Tug
« Reply #17 on: January 23, 2010, 06:22:54 PM »

Looks very impressive, can't say much more! Keep us posted on progress, Dave :-))
Logged

TugChief

  • Guest
Re: Modern Harbour Tug
« Reply #18 on: January 24, 2010, 08:26:29 AM »

Hi Toesupwa,

The pivot point must be counted as the last point the the tow rope is in contact with the tugs structure and as you correctly point our your towing point (Staple) is aft of the units.  If you look at the configuration of any single, twin or ASD propelled tug you will find that the towing point is just aft of midships, mush further forward that on your vessel.

The easiest way to explain i feel is in terms of vessel rudders.  These have developed over the years and there are three basic types which have been used over the past century or so;

Fully Balanced.  This is when the rudder stock is almost in the centre of the rudder blade allowing equal forces to act on the area ahead of the pivot point and equally on the area aft of the pivot point.  The advantage of this is that you require a very small torque to turn the rudder, but the disadvantage is directional instability as the rudder will have a tendency to wander due to the equal forces being appled as it passes through the water.  In tug terms this would be great for a harbour tug with her towing point midships as she would be very maneuverable and would be able to pivot on her tow line with minimum rudder appled.  This direction instability always gives the danger or turning the tug over (where the tow rope comes across the beam at right angles almost midships at the towing point) and this is why a gog or gob rope is sometimes used to transfer the towing point further aft.

Semi Balanced.   This is where the rudder stock is approximately 1/3 back from the leading edge of the rudder blade.  This increases the turning torque required but gives much better direction stability.  This is the type of rudder used in all merchant vessels with a conventional propulsion package built today.  In tug terms this is what most single/twin/ASD tugs have.  This gives good maneuverability for use in harbours but still excellent direction stability for towing at sea (i.e. in a straight line).

Non Balanced.  This is where the rudder stock is located right on the leading edge of the rudder, whilst giving the best directional stability it gives the worst turning performance and requires the most torque to turn the rudder blade.  This is the category that your tug falls into.  When you are towing over aft your tug will not pivot around the towing point at all.  The entire tug will have to force the complete length of her hull through the water to change direction which will lead to using all engine power to position your tug and not the tow, this will lead to total loss of control of the tow.

You have made such a nice job of her top sides and she looks like she will be a cracking model, i would just suggest that you think about the option of placing the towing winch on the bow and towing through the lead on the bow as most ASD tugs to to avoid disappointment with the performance of your finished model.

Cheers.

Tugchief.
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #19 on: January 24, 2010, 06:50:02 PM »


The pivot point must be counted as the last point the the tow rope is in contact with the tugs structure and as you correctly point our your towing point (Staple) is aft of the units.  If you look at the configuration of any single, twin or ASD propelled tug you will find that the towing point is just aft of midships, mush further forward that on your vessel.

You have made such a nice job of her top sides and she looks like she will be a cracking model, i would just suggest that you think about the option of placing the towing winch on the bow and towing through the lead on the bow as most ASD tugs to to avoid disappointment with the performance of your finished model.


Thanks Tugchief...
That goes some way to explaining what to expect with a tow... though with the two Z drives under the stern, I'm still tempted to try it 'as is' and see what effect it has.. I can always cut off the rear staple at a later stage and tow direct from the winch and 'H' frame...

I cant move the winch to the bow, there is not enough room either within the depth of the hull or across the width of the hull to fit it in...  {:-{
Logged

tugnut

  • Guest
Re: Modern Harbour Tug
« Reply #20 on: January 24, 2010, 07:42:02 PM »

Great tug, that is one brilliant job you are doing Toesupwa.

One IMPRESSED John b
Logged

lighterman

  • Guest
Re: Modern Harbour Tug
« Reply #21 on: January 24, 2010, 11:15:43 PM »

Fantastic work so far! i am in the throws of making a plug up for my next project only wish it turns out at 1 10th as good as yours and i will be over the moon.
i was thinking of adding the plate detail to the plug do you think it will work as i have yet to get my sticky hand all over a mold!
cant wait to see your model as you do further work.

are the Korts turned from ply wood laminated into a block? what angle did you set the top slide over to on the turning?
regards

Martin
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #22 on: January 25, 2010, 12:05:02 AM »


i was thinking of adding the plate detail to the plug do you think it will work as i have yet to get my sticky hand all over a mold!
cant wait to see your model as you do further work.

are the Korts turned from ply wood laminated into a block? what angle did you set the top slide over to on the turning?


You could try adding detail to your plug / mold / hull.. but if its your first attempt, I wouldnt advise it.. Get a decent hull out of the mold first and then do a second mold from the plug with detail when you have some experience..

Yes, the kort's are wrapped ply around a 'plug' i turned to the specific dia. of the props...
The full 'story' on making the kort's is here..
http://www.rcgroups.com/forums/showthread.php?t=1025555
Logged

lighterman

  • Guest
Re: Modern Harbour Tug
« Reply #23 on: January 30, 2010, 12:41:28 AM »

Thanks for the tips! your other posting the other web site is great. last time i made some i did is by casting resin in a yogurt pot then bored it out in the lathe thinking back it i put one pot in another i could have use less resin.
my cardboard plugs are ready for final sanding and then laying up the GRP mold
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: Modern Harbour Tug
« Reply #24 on: January 30, 2010, 01:15:28 AM »

I've made up the window frames with some railway line.. and the wheelhouse roof and lower superstructure handrails...

 %)
Logged
Pages: [1] 2 3 4   Go Up