Ship Maintenance Periods

Overview

If someone were to ask, “Are ship’s ALWAYS on the go?”, the answer would be “Yes*”. Did you notice the asterisk? Well I put the asterisk there because ships ARE, indeed, always on the go, when they are available. For this example, we will use a standard merchant ship, such as a container ship or an oil tanker. For these types of ships, time is money.

The more efficient the ship can be, the more money it makes the company. So, if a company owns one of these ships, and it is available for use, it will ALWAYS be on the go. Now, like with anything, there are some caveats to this statement, such as when a ship is being held up by outside entities, such as when the ship is waiting for a tugboat, pier space, etc. As a rule-of-thumb though, ships cost a lot of money to operate, and they don’t make any money when they’re just sitting around.

Now that we got the above information out in the open. I’ll go into a bit of detail on what ships’ schedules are like.

Repair Periods

Big ship’s need love to. As stated in previous articles, ships have thousands of parts and hundreds of large pieces of machinery, which are put to heavy use and beat down pretty good. Therefore, over time, repairs and regular maintenance needs to be conducted in order to keep the ship’s body and machinery in good working order.

What is a Repair Period?

There’s no hidden meaning here. A Repair Period is just what it says, a period of time the ship’s owner has set aside to get the TLC that is needed for routine or urgent maintenance. I will also mention that there are many names for “Repair Periods”, some of which are an Availability, a Shipyard, a Yard Period, a Maintenance Period…etc. I’m sure there are more but that’s all that I can think of off the top of my head at the moment besides a “Dry Dock”, which is a special type of Repair Period which will be explained below.

The process for scheduling a shipyard repair period involves the ship’s owner finding an appropriate shipyard, getting contracts for a list of maintenance items that need to be conducted during said repair period, and getting the ship to that shipyard on time.

How do you know what maintenance will be performed in a Repair Period?

Well, I can’t remember if I stated this in a previous article yet, but I will give a brief answer to this question here. All the machinery on a ship comes with certain maintenance schedules provided by the manufacturer.

Obviously, machinery can’t be used if maintenance is being performed on it. Let’s say that the Main Engine needs a complete overhaul every 5 years according to the manufacturer. The engineers on the ship aren’t going to be doing a massive maintenance job like that underway, nor could they be expected to do so. Therefore, this would be the type of maintenance item that would be scheduled to be performed in a repair period. Does that make sense?

There are many pieces of equipment that are required to be operational in order for a ship to be operationally available (remember, this industry is extremely highly regulated). Therefore, anytime that one of these pieces of equipment needs maintenance, that maintenance is usually conducted during one of these specified repair periods.

Are there different types of Repair Periods?

I’m so glad you asked. Yes, as a matter of fact there are. Below, I’ll go into some detail about a few different types of Repair Periods.

Regular Repair Period (Availability, Yard Period…etc)

This is when the ship goes to a certain shipyard, which could be anywhere in the world, in order to get regular or emergency maintenance performed that doesn’t require any special accommodations. Depending on who owns the ship and how bad of shape the ship is in and what repairs/upgrades are being made, a yard period can be anywhere from a few days to many months in duration.

Dry Dock

A dry dock is a special type of yard period in which the ship essentially goes to a special dock that has gates that close and seal, preventing the entering or exiting of water. Once the dry dock is sealed, the ship is placed on large blocks (yes, literally blocks) while all the water within the dock is pumped out, leaving only the ship sitting (hopefully securely) on the blocks.

Why is this necessary? There are a lot of critical parts of the ship that are below the waterline, and ships take in seawater during operation and use it for many things (mainly cooling but also to make water). So, along with the hull, the propeller equipment, and the ship’s rudder, there are all types of water intake piping and other items that need maintenance and inspection.

If a simple inspection or minor maintenance is needed for something under the waterline, divers often will be called to complete the work, but for anything major or more involved, such as repainting the hull, or conducting maintenance or an inspection on the Stern Tube Seal (the seal that seals the seawater and prevents it from entering the ship through where the propeller shaft comes out of the ship), or many other items, it is necessary to enter a Dry Dock period to get this maintenance completed.

Mobile Dry Docks

Believe it or not, there are such things as mobile dry docks. They are big bathtub-looking things that get towed around and can be placed in different locations. Once secured, they can be used as regular dry docks. Crazy right?

I will be sure to go into more detail in future articles as well describing how ships interact with water and use it as they operate.

Recap

In this article, we went over a general explanation of what repair periods are and how they work. We also went over specifically what a dry dock is and why the use of a dry dock may be required as opposed to a regular pier-side repair period. As stated before, in future articles we will explain more about each of these topics but you can also reach out via the ‘Contact’ section of this site for any questions you may have. Enjoy!