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Import substitution and shipbuilding

A couple of years ago they set me the task of designing an outboard ladder for a ship. On each large ship there are two of them: right and left.

Outboard gangway

The steps of the ladder have a cunning semicircular shape, so that they can be stood at different angles of inclination of the ladder. They hang the net so that people and objects that fall out do not fall on the pier or in the water.

The principle of operation of the ladder can be simplistically described as follows. When the rope is wrapped around the winch drum 5, the flight of stairs 1 is pulled to the cantilever part of the gangway 4. As soon as the flight rests on the console, it begins to rotate relative to its hinged attachment point, driving the shaft 6 and the swing-out platform 3. As a result this march of the ladder falls on the edge, i.e. in the "marching" position. When reaching the final vertical position, the limit switch is activated, which stops the winch.

Kinematic diagram of an outboard ladder

Any such project begins with a study of the technical specifications, regulatory documents and existing analogues. We will skip the first phase, since the technical specifications contained only requirements for the length of the ramp, the temperature range of operation, completeness and compliance with a number of industry standards.

As for the norms, they are set forth in a single multi-volume document, “Rules for the Classification and Construction of Marine Ships.” Compliance with these rules is monitored by the Russian Maritime Register of Shipping or abbreviated RMRS . Having studied this multivolume work, I wrote out on a piece of paper those points that relate to the outboard ladder and winch. Here are some of them:

Rules for the lifting devices of marine vessels


1.5.5.1 , , , .
1.5.5.7 , , , .
1.5.6.6 , , , , .
9.3.4 (, ).

In the third phase of preparation for the design process, using the omnipotent Internet, I collected a daddy with images of ladders. From studying these images, the hair on the head began to move. A lot of proposals for the purchase of gangways were found on sites such as Alibaba. For example:

Cheap low quality outboard gangway

  • In hinges, the steel axis rubs along the steel eye;
  • There is no protection against the loss of the rope from the stream of the block in the absence of tension;
  • The platform is made of a continuous sheet. With the formation of ice, its operation is not safe. It is better to use a trellised flooring (though it is not very convenient if you are wearing high heels);

Let's see another picture: The

Cheap low quality outboard gangway

fastening of the aluminum round pillar to the aluminum march is made by a galvanized bolt. There are two problems here:

  • The steel bolt will quickly “break” the hole in the aluminum to an ellipse and the structure will hang;
  • The contact of zinc and aluminum causes electrochemical corrosion, especially in the presence of sea water at the contact point;

And what about the winches?

Cheap low quality gangway winch

  • Since the winch is on the open deck next to the gangway, it is better to put the engine upright instead of horizontally to save space;
  • The paint from the steel drum quickly wraps around and the corrosion process begins. Responsible persons will be forced to regularly tint this mess with a brush;

Further it became even more interesting. Using personal contacts at some shipyards, I managed to see what they put on their current projects. Here at one factory I photographed the fastening of the guard racks to the march:

Poor fastening of the guard racks to the march

Gaps are huge. The fence will hang like a pig tail. Acute traumatic corners. And here is the plastic winch console:

Plastic winch console for cheap outboard ladder

One fall on a steel deck on a frosty windy day and it will fly apart.

The winch on another vessel was hidden in a heated casing with heating:

Low-quality winch for outboard

The heated gearmotor solution itself is normal. This is due to the fact that a drive with an acceptable operating temperature below minus 40 degrees cannot be found. And for icebreakers, as a rule, minus 50 is indicated in the statement of work. It is economically more expedient to buy and heat up a serial model of a gear motor than to order a special version from the manufacturer. But, as in any business, there are nuances:

  • With the casing closed, the laying of the rope is not controlled, which contradicts the rules of RMRS. There should be a rope stacker;
  • The handle for manual brake release is visible, but the handle for manual rotation of the motor shaft is not visible. GOST R ISO 7364-2009 “Deck mechanisms. Gangway winches ” prescribes to equip with a manual drive all winches operating at low load. That's just the concept of "light load" in the standard is not disclosed;

Let's look at the gangway:

Gangway from low quality outboard gangway

  • There is no protection against the loss of the rope from the block. As soon as it sags, for example, when it touches the pier with a ramp, it will immediately jump out of the stream. With subsequent tension on it will appear hall and the whole rope will need to be changed;
  • It seems that something is wrong with the trace of the rope. On a horizontal discharge roller, the rope bends downward;

Already on another vessel, we observe how the pulleys of the blocks stand on the axes, regrind from the bolts. The likelihood that there is a bronze or polymer anti-friction sleeve inside, as required by the RMRS rules, is minimal:

Gangway from low quality outboard gangway

I managed to photograph the following ramps at the Blagoveshchensky bridge and on the Lieutenant Schmidt embankment (St. Petersburg).



In many places, the rope rubs about the metal structure:

Cheap low quality outboard gangway

Cheap low quality outboard gangway

And here is the fastening of the removable fence rack to the site:

Cheap low quality outboard gangway

About the flag clamps that hold the round posts, I’ll tell you the beautiful story that the person who dealt with them told me. The latch flag always tends to turn vertically down under its own weight. Accordingly, when installing or removing the latch there is a chance that the flag will turn down at the moment when it will be inside the rack. As a result, the latch gets stuck and does not go either inward or back. The stand cannot be removed, the ramp cannot be removed, the ship cannot move away from the pier, the shipowner is losing money.

The next picture I will not surprise anyone:

Cheap low quality outboard gangway

In the hinge, steel rubs on steel. The paint has already peeled off, despite the fact that after installation this place was already painted. This is evident from the painted bolts.

Let's see the winch:

Winch from a cheap low-quality outboard ladder

  • The paint is already peeling off the drum;
  • Grounding wiring will not last long;

I didn’t swim on the icebreaker, but here is a photo from the Internet about cleaning the deck:

Icebreaker deck cleaning

The layout of the winch does not exactly facilitate snow removal, the wires will very quickly damage the shovel. Chinese nameplate with a winch:

Shilda with Chinese winch for outboard

Judging by the marking, the lower limit of the operating temperature range is minus 25 degrees. And the ship has the prefix "icebreaker".

Not a single winch did I see a system preventing the complete unwinding of the rope from the winch ("protection against the fool"). That is, if you hold the button on the remote control, the ladder will fall lower and lower until the rope ends. After that, the closing of the rope will come off and the ladder will fly down (the closing of the rope itself cannot bear the load; the force is transmitted through the friction force arising between the drum shell and the first few turns of the rope).

Let me remind you that all these photos are from new or from ships under construction. This is a new equipment that should be created taking into account world experience and all modern trends in engineering and shipbuilding. And it all looks like a home-made assembled in garages. RMRS rules and common sense are not respected by most suppliers of marine equipment.

I asked a question on this topic to a specialist from the procurement department of one of the plants. To which I received an answer that for all purchased ladders there is a certificate of RMRS on compliance with all necessary requirements. Naturally, they are bought through tender procedures at the lowest cost.

Then a similar question was asked to a specialist from RMRS and he said that he personally did not sign certificates for these ramps and he would never miss such a thing.

The ladder that I designed, of course, was designed and manufactured taking into account all the aspects that I talked about:

  • Stainless steel drum with single layer winding and rope stacker;
  • Pulleys made of stainless steel with protection against loss of the rope;
  • Plain bearings with anti-friction polymer bushings that do not require lubrication;
  • Wires in silicone insulation and steel braid;
  • Vandal-proof metal control panel;
  • The removable handle of a manual drive on a winch with a power protection system with the handle removed;
  • Protection against full unwinding of the rope from the drum;

The perfect outboard

I can’t show it in detail in this story, because I will violate the exclusive rights of the customer to the design documentation developed by me. Trap received a certificate of RMRS, was shipped to the shipyard and has already been transferred to the final customer along with the ship. That's just the price he turned out to be not competitive and it is unlikely that he will be able to sell it to anyone else.

On this I will end the story so as not to offend customers, shipbuilders, competitors and representatives of RMRS. You can draw conclusions about the state of affairs in shipbuilding yourself.

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