Author Topic: "Boxing" the rudder.  (Read 3340 times)

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tug-arlyn-nelson

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"Boxing" the rudder.
« on: July 25, 2015, 10:30:00 »
This no doubt has other names, but I recall many years ago being around tugs and owners a lot in Seattle and Alaska, talk of "boxing" in the rudder. This amounts to having a couple of stand offs on each side of the rudder, then laying large plates on those to in effect create a box or tube for the wash to pass thru on its way to the surface. I do know of one tug I worked on in Seattle that had some boxing done to its rudder. This helps to force the wash down and aft rather than coming up immediately under the counter and being what we used to call a "bubble-*bottom*" tug. Or as my dad used to call them " all fuss and bubbles". In other words, not a hard puller per its horsepower. Usually such boats were of shallow draft per their length as well. With my Dumas CAROL MORAN which I recently had gone to a larger diameter prop of five blades, I feel it pulls better but still is a bubble *bottom* with its wash coming right up, though not as pronounced as it was before with its 3 blade 1"  prop spinning real fast, no gear. So I decided to experiment with the rudder and last night boxed it in. I put it in the fresh tank today and I could tell immediately the difference in the wash as instead of it coming right up, it was decidedly aft of where it used to be. I plan to go down in a bit and put the barge behind it and see if it actually pulls any harder or just changed the wash pattern. Will post again later with results.

tug-arlyn-nelson

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Re: "Boxing" the rudder.
« Reply #1 on: July 25, 2015, 10:56:37 »
Frankly I am little surprised to see that my post was modified by someone to edit the word as* from bubble as* to bottom!  Really?  Are we not all adults here?  The word  as* is highly offensive is it? It fairly describes about half the population of the US!  Seafaring men used and have a fairly colorful vernacular. I mean come on!

fastfaz

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Re: "Boxing" the rudder.
« Reply #2 on: July 25, 2015, 11:59:49 »
Yo tug ,
     I see where you are coming from! I posted a quote from Terry Pratchets book "Pyramids" about the greatest mathematician in the world the camel "you B+++++d" this was removed, it doesn't have the same ring as you illegitimate I think. Heaven forbid we offend someone by not being politically correct! I wonder how long it will be before the other side (not allowed to say what I really mean) take over? Politicians Man up.
    Cheers,
       Faz.
     
The photo is my Lowgarth Mountfleet models but my own design and build (the kit quality and fit was very poor) I scatch built the superstructure from photos of the Foylegarth and scaled it off the figures. Sails superbly.

CGAux26

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Re: "Boxing" the rudder.
« Reply #3 on: July 25, 2015, 12:13:35 »
Back on topic, does "boxing" the rudder have any effect on prop walk, going astern?
Dave

tug-arlyn-nelson

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Re: "Boxing" the rudder.
« Reply #4 on: July 25, 2015, 13:37:03 »
Fastfaz, yep, seems to be the way things are now. I mean as*!  Big deal!


tug-arlyn-nelson

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Re: "Boxing" the rudder.
« Reply #5 on: July 25, 2015, 13:41:05 »
Back on topic, does "boxing" the rudder have any effect on prop walk, going astern?

Yes, it does. I just had it down to the water and it does give more control in back up, no question. Like having 3 rudders. Also makes it a bit squirrely on hard turns going forward at speed.   I will post some vid later. It for sure changed the wash pattern, it comes up much farther behind and is much less apt towards the roostertail effect. I cannot say with certainty that it pulled my barge any faster however. I do like the new wash pattern much better though. Thanks guys!

olscuzbut

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Re: "Boxing" the rudder.
« Reply #6 on: July 25, 2015, 15:32:45 »
Sort of like a 4 cornered steerable Kortz nozzle . lol.

tug-arlyn-nelson

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Re: "Boxing" the rudder.
« Reply #7 on: July 25, 2015, 15:47:21 »
Yeah kind of.  I remember my old dad sailed on a V4 tug during the war. It had a steerable Kort and he said it wandered all over the ocean. The best helmsman couldn't keep her on course!  Skipper chewed him out and said let me have her a minute. He couldn't keep her on course either, no more whining after that.

des

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Re: "Boxing" the rudder.
« Reply #8 on: July 25, 2015, 16:01:12 »
"Boxing the rudder" - this sounds like an early development of the three-rudder Towmaster rudder system.

Des

tug-arlyn-nelson

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Re: "Boxing" the rudder.
« Reply #9 on: July 25, 2015, 17:26:57 »
I have no idea where or when it was first used, just remember it from my own tugboat days. Here is a vid showing my barge alongside today and it clearly shows how the wash comes up well aft of the boat where if you look at some of my earlier vids when I first made this model, it was all fuss and bubbles right astern.




https://www.youtube.com/watch?v=p5ZgA8IK2Xc 

tug-arlyn-nelson

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Re: "Boxing" the rudder.
« Reply #10 on: July 25, 2015, 20:11:02 »
https://www.youtube.com/watch?v=_hnPRSCgYGg

Here is another that really shows how it helps with barge handling.