SS Hydrograaf, 1/100 3D, hydrographic ship, Royal Dutch Navy

[wefalck]

Effective ready-made anti-fouling paints for iron ships came unto the market in the 1860s, in particular those based on the development of the Bremerhaven captain John Rahtjen. They were available in different colours, particularly also the oxide red (being cheap). Rahtjen paints are still on the market, I think. In case you read German (or use Google Translator, here is a quite good historical overview (not in all points correct, I think): https://www.classic-forum.org/images/Bu ... nderte.pdf.

[Iceman 29]

Thank you both for these interesting informations!

End of hull hollowing. Started the rear grating where the steering wheel and gear are located.

[wefalck]

The grating covers the rudder quadrant that itself is connected to the bridge via steel rods and chains. In the back there is only the emergency steering apparatus.

[Iceman 29]

Yes, that's exactly it.

Like on the SS Nomadic at the time.

SS Hydrograaf:

[Iceman 29]

Small progress on the emergency steering wheel system. It's not finished yet.

I did not remake a wheel, it is in my 3D drawing stock that I made and was intended for the Nomadic.

I would just delete the English language markings on the wheel.

[Fliger747]

From the rudder shaft below, the stern wheel will rotate along with inputs from the pilothouse?

Most interesting historical documentation!

Regards: Tom

[wefalck]

This was the standard arrangement until hydraulic systems came into use, I gather after WW2. On bigger vessels the steering apparatus on the bridge was steam assissted.

It is not clear from the pictures, but it looks as if on the real ship the emergency steering apparatus is not connected anymore.

[Iceman 29]

The cables were replaced by hydraulic cylinders probably later. This is safer and more powerful and less of a strain on the steering wheel, it also allows an autopilot to be connected, especially as the rudder has been extended aft to make the ship more manoeuvrable in port.

You can see the hydraulic hoses going down below deck to the 2 jacks.

You can also see the rudder stock and its stuffing box to the right of the hoses.

[Maarten Sch�nfeld]

From the rudder shaft below, the stern wheel will rotate along with inputs from the pilothouse?

Most interesting historical documentation!

Regards: Tom

Hi Tom,

I don't think so: the emergency steering apparatus is probably using a screw spindle, to act on the rudder stock via a linkage. The side view indicate something like this:

As you know, it is impossible (due to friction) to make the spindle turn by the rudder pressure through the linkage. This is also made for safety, that the steering wheel cannot be sent spinning (with great danger to the crew) by an incoming wave. So the transmission is not reversible. Therefore there must be a clutch to connect the emergency steering mechanism to the rudder stock.
(Image from this Dutch site: http://zienenweten.blogspot.com/2015/04 ... s-dat.html)
Actually here the corresponding top view from the Hydrograaf itself, from the Dutch archives drawings:

[wefalck]

Thanks, Maarten, I just had been looking for an illustration of a screw streering apparatus to show this. A screw with a certain maximum pitch is self-locking, meaning that you cannot turn the spindle by pushing on the nut(s).

[Fliger747]

Thank you! An interesting explanation of the mechanism. My small airplane uses a jackscrew for the stabilizer trim and likewise air loads on the stabilizer will not spin the handle in the cockpit. A breaking of the nut on the screw will allow the surface (such as the stabilizer on a jet aircraft) to move without control such as happened to an Alaska Airlines jet off Los Angeles quite a few years ago.

What I was originally thinking of was the rather old time use of ropes, drums and pulleys from the age of sail. When we know how and why a system works we can better model it!

Again Thanks!

[wefalck]

"When we know how and why a system works we can better model it!" ... Exactly, I actually have difficulties to model something, when I don't understand it.

[Iceman 29]

@ Maarten, thank for the documentation.

I'm missing this top plan which handicaps me a bit to continue the drawing of this ship. I'm afraid of drawing nonsense, that would be a shame.

If you have the link to the archives, I'm interested, thanks!

"Actually here the corresponding top view from the Hydrograaf itself, from the Dutch archives drawings:



"

I sailed in the 1980s on a 90 metre coastal tanker built in 1980. The steering system was of course hydraulic with 2 pumps and two jacks, the last resort was still by blocks and ropes.

This was not easy to implement due to the size of the rudder. And it required a lot of manpower!

[Fliger747]

I remember seeing a photo of one of the Kriegsmarine WWII Heavy Cruisers being steered by such means. My recollection was that for some reason the stern had cleanly separated, much like Bismarcks. Warships of the day at least, compared to their civilian counterparts had a great supply of manpower. I suppose such a system might get you to some location where tugboat assistance was available. Aircraft up to a certain size have manual reversion available, executed with tabs that cause the larger surface (ailerons) to assume a new balanced position. Some aircraft I have flown have no manual reversion, the C-130 being one, the 747 also falls into this category but there are four hydraulic systems (five on the Dash Eight). My estimation of the fly by wire systems is this is further vulnerability in the chain of events between the pilot and actual control. A couple of years ago a Sukhoi Superjet 100 crashed at Moscow, returning after a lightening strike on departure. My estimation after watching the video's of the crash was it was a similar situation to the Sioux City DC10 crash where flight control was lost. It appeared that the pilot was using trim to control the pitch which was too slow in reaction and it over controlled after an initial bounce resulting in a very hard impact, the collapse of the landing gear rupturing the fuel tanks.

There were a number of USN steering casualties during WWII in combat, notably Enterprise going uncontrollably in circles during an air attack.

Indeed the current configuration of Hydrograaf the stern steering position appears to be mostly for "entertainment" purposes.

[Iceman 29]

Thank Tom for this explanation.

I've found the missing plan in HD ans some others, very usefull !

https://www.nationaalarchief.nl/onderzo ... ~4322-4323

https://www.nationaalarchief.nl/onderzo ... b=download

[Maarten Sch�nfeld]

Pascal,

If you have the link to the archives, I'm interested, thanks!

The link to the relevant archive numbers (4324 to 4340, 17 drawings on this ship alone!) can be found here and are free for downloading:
https://www.nationaalarchief.nl/onderzo ... ~4324-4340
Enjoy!

To Tom: I believe this was a patented steering construction from the late 19th century. This fully manual system could be adapted beautifully for hydraulic powering as well, very similar mechanisms I have seen on the plans of RMS Mauretania, Titanic and HMS Hood to name a few.

Your reflections on large aircraft control systems is interesting indeed: I did my time as a flight engineer in DC10 aircraft. In fact a little more sophisticated than the 747 I think, but that might have changed in the newer versions of the latter of course. And the basic truth was put very well by Wefalck: if you don't understand the systems you might be in for trouble sooner or later... Does that sound like the recent Boeing 737 MAX problems, Boeing putting in a new control system without clearly explaining to the pilots what they had done? And not even allowing for overriding this apparatus?

[Maarten Sch�nfeld]

Thank Tom for this explanation.

I've found the missing plan in HD ans some others, very usefull !

https://www.nationaalarchief.nl/onderzo ... ~4322-4323
...

Be careful Pascal, that link is to the first ship of the same name, that existed from 1873-1890. Don't confuse the two!

[Fliger747]

I read extensively about the MAX problems. It was an effort to bypass an undesirable flight certification issue caused by the forward position of the LEAP engines with their large nacelles. Certification requires that control pressure for the elevator must continue to increase through the stall. At high AOA the nacelles began to develop lift moving the center of lift forward and lightening the control force. Boeing countered this by sending a signal to the trim motor. A better system might have been to have a control feedback like the speed "feel" on the 747 which changed the force on the wheel, not a control surface movement. Just increase the yoke force at high AOA.

Of course all this could have been fixed with (1) a MCAS in motion light with a (2) MCAS OFF switch. But maybe that's too simple of a solution.

The early 747's I flew had flight engineers and I enjoyed working with them. Always fun on a layover! The 400 and -8 were an easier ride as we had extra flight crew members and on a long flight go take a nap.

That you are able to access such drawings in the archives is a wonderful resource for modelers and historians. Modeling an existing or recent ship has many advantages though modifications though one can never have enough photos!

Looking forward to see the classic Hydrograff take physical form! Always learn something!

Regards: Tom

[Maarten Sch�nfeld]

That you are able to access such drawings in the archives is a wonderful resource for modelers and historians. Modeling an existing or recent ship has many advantages though modifications though one can never have enough photos!

Yes, it certainly is! My current modeling project is reconstructing a Dutch Napoleonic ship of the line, and I found the relevant drawings in the same Dutch National Archive: here you can read all about this: viewtopic.php?f=13&t=317938

Unfortunatly no photos were avialable in 1816-1827, but I'm amazed how much can be learned from paintings too! But you need to be very critical then of course.

Having boasting on the Dutch Archives: of course there are also many other good sources for this sort of drawings, like the British National Maritime Museum. Unfortunately they need to be cost neutral and therefore charge heavily for providing copies. Very unfortunate for modelers. For US ships Floating Drydock is often a good source, and so is the HNSA of course.

[Iceman 29]

Unfortunately, the French archive of plans has been closed on line from an "excessive use". But some plans can be found on different sites.