Why Do Tugboats Sometimes Push Instead Of Pull?

Some of the marine terminology can get confusing and many conflate distinct types of watercrafts together. For instance, there are many differences between a tugboat vs. a towboat. However, what can't be underestimated is the importance of these small but powerful means to help ensure the safety of mariners and goods. According to UN Trade & Development, water transport of goods and materials is central to the economies of countries across the globe, with more than 80% of global trade volume hauled across the seas. Tugboats and towboats are there to help maneuver these larger vessels along the correct path.

In general, you might see a tugboat pushing a large vessel instead of pulling it, because it's more productive from an energy expenditure perspective. Large barges can also waver from center laterally when being towed, so some situations call for pushing, which provides a greater amount of control.

With the ability to more finely articulate a ships movement with pushing, you'll find tugboats employing this method in more congested waterways. These tugboats often feature bows equipped with large bumpers and more robust hulls to handle the rigors of coming into direct contact with huge ships.

There are certain maneuvers that require a tugboat to push and some to pull. For example, if a ship needs to be rotated clockwise or counterclockwise, this operation would be referred to as indirect towing, which is a bit confusing because it involves tugboats pushing on strategic points of the larger vessel's hull, to spin it.

Another instance when pushing makes sense, is during a berthing maneuver, where tugboats are pressing against the hull of the colossal ship, moving it laterally to line up with the dock. However, other vital actions, such as when unberthing a ship (moving it away from the dock laterally), pulling is the preferred method. In addition, if a single tugboat is employed, it can be tethered to the bow or stern of ship to reduce its momentum by pulling in the opposite direction.

However, there are other circumstances in which towing is preferred for a tugboat. One of the deciding factors between a tugboat pushing or pulling, is the roughness of the water's surface. For example, in choppy conditions, if a tugboat were to attempt to push a container ship, instead of controlled contact between the two, waves would likely cause unavoidable and numerous collisions. If you've seen first-hand a tiny vessel pulling a mammoth one behind it, it might seem almost unbelievable, but there is a secret behind what makes tugboats strong enough to tow massive ships.

There are several factors at play when ports are determining how many tugboats are needed for any given operation. A ship's gross tonnage, its dimensions, and environmental considerations all apply when planning on the number of tugboats.

This isn't an easy process either, as wind speed, and underwater currents are continually evaluated in terms of how they will act upon the various parts of a specific ship, both above and below the water line. This involves complex formulas and calculations, so it's clear what specific positioning each tugboat must make, and at which intervals during a maneuver. After all, multiple tugboats must work smoothly together, to accomplish their tasks efficiently and quickly.

While some navigation might only call for a single tugboat, others, particularly emergency situations may require many more. For instance, back in 2021, the Suez Canal in Egypt became blocked for several days, as the Ever Given (a massive container ship) got stuck. It required the use of 14 tugboats, and dredgers (vessels that dig underwater), to extricate the Ever Given. While tugboats are primarily known for directing large ships, that isn't their only function, as the Navy's charming barrier tugboats, known as the Boomin' Beavers conduct other maneuvers in their harbors.