The Art of Dredging

Dredging and shipping

Mooring a dredger. A piece of cake ?!

This article deals with mooring a dredger, “for dummies”.

When I talk about “a dredger”, I see a twin screw vessel, with minimal one bowthruster. This vessel will be in ballast, and thus overpowered.


Follow simple rules –see below- and mooring a “dredger” is bulletproof.

 

Rule nr.1:

Move the vessel parallel to the berth, push it sideways to the quay.  This is a golden rule.


You can find the heading alongside the berth on your ECDIS, or ask the pilot.

Keep the vessel exactly on that heading when berthing, and push the vessel sideways to the berth.

That’s right: look at your compass. 

Don’t look too much at the berth (which tends to make conning officers nervous anyway.)

 

Rule nr. 2:

Come close, go slow.

If you are close to the quay wall, go into “safe mode”: 

manoeuvre with minimal power on thrusters.


A few meters from the berth is not a good moment to behave like a cowboy. 

Manoeuvre like your grandmother would.


Rule nr. 3:

Bring the vessel in position first, alongside the berth, push it against the fendering. 

If the vessel is completely stable, start putting mooring lines.

Pulling a dredger to the berth with mooring lines –like a wounded whale- is unnecessary, you will increase risk and loose control.

 

Rule nr. 4: 

If you need tugs (sometimes it’s compulsory) ask them to sail along with slack towing lines.

Most tug captains express their own ideas by pushing / pulling vessels around.

These guys have a central role in berthing large vessels, can’t blame them.

While the aim of this article is to bring a dredger alongside “under her own power”.

 

Some more hints:


  1. Do not stop the vessel by sailing into spring lines
  2. That looks cool, but with an empty, overpowered dredge, you may break that mooring line. And kill crewmembers.
  3.  When the vessel is closer than five meter from the quay, somebody has to report distances fore- and aftship from the quay.  A compass is not accurate enough that close to the berth. A one degree error on the compass can be a 3-4m error in parallelism on a LOA 200m vessel.



There is nothing wrong with keeping it simple.

 






Marc Van de Velde
August 2017