dafi

Thinking things through: axiometer or helm indicator

Through my quest about the details in Turner´s drawings*** we got into a nice discussion about axiometers in our german forum.

 

Harland mentions one form on the poop deck´s deck beam on top of the wheel, he mentions a contemporary model in the NMM and this is where the information ceases, no luck nowhere, even at google ...

 

Any idea of what model this was and how this axiometer worked? 

 

XXXDAn

 

***http://modelshipworld.com/index.php/topic/13182-thinking-things-through-detail-in-turners-work-on-the-poop-deck-railing/

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Interesting thought, Dan.  I can come up with several definitions (interestingly, none in english) that describe it as essentially a rudder angle (tiller angle) indicator.  The other definitions all describe a method using lenses to determine alignment, also for use in fitting spectacles.  Will keep looking.

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If it is indeed a rudder angle indicator, HMS Warrior has one on her wheel.  It is a partial circle with zero at the top and numbered down to three on each side, the scale ending at about 4 and 8 o'clock.  I presume there is a gear train in the hub to turn the indicator needle as the wheel is turned.  I won't post a copyrighted picture, I googled hms victory wheel then images.

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Here is a picture out of my own stock of the Warrior´s axiometer :-)

The axiometer can be seen on the left side of the drum´s axis.

 

post-182-0-38455600-1460219103_thumb.jpg

 

Here are two links to the french Arsenal Forum from the french version:

 

http://5500.forumactif.org/t2176-axiometre#61558

 

http://5500.forumactif.org/t595p25-model...rre-blanc#19592

 

http://5500.forumactif.org/t595p400-mode...rre-blanc#77632

 

Also the different wordings like helm indicator were a good hint :-)

Thank you all!

 

And I have some very interesting finds from my german forum, the puzzle is taking form, soon more :-)

 

XXXDAn

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Looked at some sources for more than a hundred times but needed the help of my german forum mates to poke my nose onto this detail and I was able to put the puzzle together.

 

There are some helm indicators shown in NMM one of them on a ship that is quite dear to me ;-)

And both shown examples on contemporary models!

 

large.jpg
 
SLR0512 Scale: 1:60. A model of H.M.S Victory (1765) made entirely in wood that has been painted in realistic colours with metal fittings. The vessel is shown in a launching cradle on a slipway. The hull is painted white below the waterline with a closed black wale above. The remainder of the hull is varnished, and laid in individual planks. There are three gun decks and all the gunports are depicted in an open position, the inner faces of the gunport lids are painted red as are the insides of the gunports themselves. A decorative frieze is painted on a blue ground that runs the entire length of the hull just above main deck level. The figurehead is finely carved depicting George III, allegorical figures and a Union flag on the starboard side. Other bow details include a pair of whisker booms, a pair of catheads, one large admiralty pattern anchor, and one small anchor. The model does not have any masts but instead has three launching flag poles. Foredeck fittings include a bell and belfry, stove chimney, and a forward launching flag pole. The waist has been closed in and four beams support a ship’s boat equipped with a number of red-painted oars. Beneath the boat on the main deck are two sets of gratings. The upper deck fittings include the ship's double wheel painted red, and two companion ways that provide access to the poop deck. The poop deck fittings include a rectangular skylight, launching flag pole, hammock stowage rails, and provision for an ensign jack staff. The stern and quarter galleries, of which two are open, are elaborately carved and painted, and glazed in mica. The launching cradle and slipway is realistically depicted and there are six stabiliser poles attached to the port and starboard stern quarters and the sides of the slipway.
Date made Mid-18th century
 
Also to be seen on the Royal George (1756) in NMM, rather small but if one compares to SLR0512 one can see the same thing:
 
large.jpg
SLR0336 Scale: 1:48. A contemporary half full hull and half skeleton model of the Royal George (1756), a first rate, 100-gun three-decker ship of the line, built in the Georgian style. The model is partially decked and has the name Royal George painted on the counter of the stern. The starboard hull shows plank on frame while the port side is unplanked to show the internal construction and layout, including numerous fittings such as galley stoves, capstans and cabin furnishings.
Date made circa 1772-77
 
And the last thing I needed was to be dragged to the detail in the red square on the Turner drawing ...
 
post-182-0-16652300-1460272906_thumb.jpg
 
...
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And on we went immediately to figure out a modeler´s solution.

 
The build was rather simple, a simple slide for an indicator moved by some thin rope to the left and to the right.
 
The pointer was bit itzy bitzy teeny weeny, a 0,3 mm drill into som 0,6 plastic ...
 
Victory-helm-indicator_9926.jpg
 
... and the test assembly ...
 
Victory-helm-indicator_9927.jpg
 
Victory-helm-indicator_9928.jpg
 
Victory-helm-indicator_9929.jpg
 
... and on my tryout model on location :-)
 
Victory-helm-indicator_9933.jpg
 
Looks smart and ingenious, learnt something new, added a nice detail to all things Victory and beyond and I am happy.
 
Hope you are too :-)
 
Cheers, Dr. dafi
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Suspect the Turner drawings are showing rain gutters. There to prevent any rain water from freely running off in sheets, drenching the helmsman along with the drenching of anyone needing to pass under that deck edge.

jud  :pirate41:

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You welcome Dafi,

On the next link you can find a color plates of the Axiometer for a 74 gun in 1785. The link is to the Museo Naval de Madrid Tecnichal Drawings collection. On page 11 look for items # 00110 and  # 00111:

http://www.armada.mde.es/museonaval/aplicaciones/coleccion-dibujos-tecnicos/#

I´m sure you´ll enjoy looking at 428 drawings available :)

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Wonderful! Thank you!

 

Is there a way to get the pictures of this collection in a higher resolution?

 

XXXDAn

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Yes I belive you can buy hi-res pictures from them. You need to contact the Museo at ohculturanaval@fn.mde.es and explain in English what you want. Don´t forget to give the signature number: Signatura Topográfica mnm_pb_number you want.They´ll tell you who to contact and how to go about with payments and mail orders. All I have from them I bought while visiting Madrid and through friends. Let me Know if you encounter any difficulty and I´ll ask the people who bought stuff from the Museo as to how they did it.

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Siggi 52 posted a nice picture of the Royal George´s wheel. Thank you loads!

 

Is there a better picture available that shows if there is any attachment or mechanism to be discovered on the model? I.e. the small drum for the rope like in the french version?

 

http://modelshipworld.com/index.php/gallery/image/13690-img-5659/

med_gallery_13971_1474_58625.jpg

 

XXXDAn

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Hello Dafi,

 

did you mean this drum? This is the plan of the Bellona/ Dragon. 

 

post-13971-0-37196600-1462204647.jpg

 

Royal George

 

post-13971-0-18188000-1462205189.jpg

 

Bellona

 

post-13971-0-16267400-1462205231.jpg

 

Bellona framed

 

post-13971-0-07857700-1462205253.jpg

 

Thunderer or as I would say Dragon

 

post-13971-0-05804700-1462205295.jpg

 

That are all pictures I have. I hope I could help.

 

Regards,

Siggi

 

 

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Thank you very much Siggi!!! Wonderful and informative pictures.

 

The interesting picture is this one:

 

post-182-0-34880500-1462209321_thumb.jpg

 

White the indicator

Green the scale

 

The question about the drum: There should be a small drum with about 3 turns (like the french system) of the steering rope moving the indicator. It is not clearly visible, but it seems that this small drum is not in between the wheel and the post in front (red arrow). Alternatively it could be in the end of the drum (orange arrow). Or was the indicator moved any other way?

 

XXXDAn 

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And todays Spanish lesson :-)

 

Thanks to Peregrino for the great work on the documentation of San Juan Nepomuceno 

 
See the original here:
 
post-182-0-08634400-1462463107_thumb.jpg
 
Interessting is the formula e/E=a/A to get the small drum´s diameter.
 
And see the display bolted underneath the deck beam, having the deflection roller incorporated.
 
post-182-0-99909100-1462463134_thumb.jpg
 
XXXDAn
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And todays Spanish lesson :-)

 

Thanks to Peregrino for the great work on the documentation of San Juan Nepomuceno 

 
See the original here:
 
post-182-0-08634400-1462463107_thumb.jpg
 
Interessting is the formula e/E=a/A to get the small drum´s diameter.
 
And see the display bolted underneath the deck beam, having the deflection roller incorporated.
 
post-182-0-99909100-1462463134_thumb.jpg
 
XXXDAn
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Just a small feedback from the tinkering corner.

 

Victory-161227_2766.jpg

 

Opted for a light colored indicator as a black one like on Royal George was difficult to spot.

 

XXXDan

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On a 64 gun ship there were seven turns of line around the drum, with the center turn nailed to the drum. There were then 3 1/2 turns possible to either side. I once worked out the geometry of this arrangement and it allowed the tiller to turn almost exactly from one end of the sweep to the other, allowing maximum helm each way.

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Yes properly done all the details fit together. The twice 7 turns (7 + 3.5 + 3.5) multiplied by the thickness of the drum and the drum´s diameter multiplied by the seven turns should give the helmway. At my Vic it fitted perfectly with the drum´s measures McKay gives :-)

 

I just realised, it wasn´t mentioned yet here. Surprisingly the helmsmen can´t see the indicator - they usually were aware of the position with the help of the master spoke.

 

The helm indicator was meant for the officers of the watch and the sail masters to see if the set sails and the helm correspond well or if the sail arrangement should be altered to ease the helm.

 

XXXDan

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Hello Daniel

 

Not that surprising actually, while not having sailing ship experience I was told that the helmsman would steer by 

paying attention to the weather leech of the topsail or topgallant (the tallest sail set) of the mast in front of him, never letting it flap

(keeping the sails full). The responsability of cheking if there was an excessive ruder angle being used (or if they were

straying too much from the course) fell on the officer of the watch, and he would call for a sail trim or order a change of course if needed.

He was the one that reallyhad to know how things were going.

 

Cheers Zeh

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