Marine Firefighting Inc.
Newsletter # 17
Maneuvering a Fireboat or Small Service Vessel Near Large Ships
By Tom Guldner
OK, your Fire Department has purchased a new Fireboat and you are now putting it in service for the first time. Hopefully you have already addressed this issue but let me ask about it anyway. Who will be allowed to steer your new boat? Is just anyone going to be able to operate this new, and expensive piece of equipment? Will your Department require any special license for your fireboat operator? If you may be operating in the near vicinity of large ships and/or barges do your operators know the dangers.
Most small fireboats do not require a licensed operator. Many Fire Departments however set up their own requirements that an operator must secure a valid Coast Guard license and there are many types of these licenses. One requirement of most marine licenses is that the applicant prove that he or she has had "Deck Time" on a vessel of the same tonnage that will match the type of license requested. Experience is the key word. If I were to pick someone to steer my boat I would look for someone who has owned or operated boats for a while. (On a boat it is called steering not driving) Many Fire Departments may already have, within their ranks, Firefighters who have worked or are still working as a commercial fisherman or on a tug/tow boat. Perhaps you have a Firefighter who has owned a boat for all of his or her adult life. Either of these Firefighters would be a prime candidate to become your Fireboat operator. If your Department further requires a license, at least these people should already have the basic knowledge, skills, and required "deck time" to satisfactorily complete the licensing course.
Regardless of the prospective boat operators experience there will be specific training issues dealing with operating a Fireboat which must also be addressed. Boat handling is a subject that cannot be taught in a small article such as this. There are, however, a few safety issues while operating near larger vessels which may not be understood, even by an experienced pleasure boater or small commercial fishing boat captain, which we will address here.
The hulls of large ships are known as "displacement hulls". This name is derived by the fact that as this vessel moves through the water it will displace a volume of water equal to the weight of that entire vessel. (Small pleasure craft may have "Planning Hulls," which rise up and ride on the surface of the water once underway.) This displacement involves massive qualities of water which are pushed aside as a large vessel travels through the water. This can be viewed as a large hole in the water. (Most disgruntled small boaters sometimes refer to their boats as, "Holes in the water in which they constantly pour in money".)
If you put your hand into a bucket of water your hand will displace a volume of water equal to your hand. This displacement can be seen by the fact that the level of the water in the bucket will rise as you insert your hand. Now remove your hand and see how long the depression your hand made in the water will remain. The surrounding water will immediately refill the area that had been occupied by your hand. (When I retired from the New York Fire Department I asked some of my fellow workers how long I would be missed. They answered. "About as long as the hole lasts in a bucket of water when you remove your hand!" New York City Firefighters are not a sentimental bunch! I THINK they were joking.)
The same thing happens as a large ship travels through the water. The vessels hull displaces a volume of water equal to its own weight and this displaced water can be seen as a "bow wake". This bow wake is merely a build up of displaced water being pushed in front of the vessel. (See photo left.). If you look behind the ship you will not notice a deep trough or hole where the ship just traveled because, just as the water filled in the depression when you removed your fist from the bucket, the water will refill the displaced water as the ship passes.
But you will also notice a raised portion of water all along the side of a fast moving vessel. This is also the wake caused by the displaced water which is trying to return to fill in the void. This displacement and attempted return of the water all along the vessels hull can create a tremendous sucking force. For this reason small boats should never make a close approach to a ship moving fast enough to create a bow or side wake.. Even the pilot boats, which transport harbor and river pilots, will not approach the hull of a vessel until that ship has reduced speed sufficiently to eliminate or greatly reduce the sucking of the ship as it travels through the water. There have been tragic cases in the past where the operator of a pilot boat or other commercial service vessel have mistakenly attempted to "come alongside" a vessel that had not slowed to a boarding speed As these vessels went over the wave or wake on the side of the moving vessel they were sucked against the vessels hull and the suction caused their boat to be pinned against the hull then capsize and sink with often tragic consequences. So, if even professional commercial boat captains can have trouble operating near moving vessels why should we expect that as Firefighters we can operate there safely. Keep away from moving large vessels.
Even traveling too closely astern of a vessel that has just passed can be dangerous. Many things create a hazardous condition in the water behind moving ships. The first thing that most people think of is the "prop wash". As the massive propellers turn they create a spinning wake that can resemble the ridges of a screw. For this reason the propellers of boats are known as "Screws". That spinning will churn up the water and can be dangerous if a small boat gets caught in this area. Another reason for the dangerous currents in the wake of a vessel is the displacement we had referred to above. All of the water displaced by the ship rushes back to fill in the void as the vessel passes. This converging water creates it's own currents which only add to the dangerous "prop wash" effect.
All right, you have accepted the above warning and you do not approach a moving ship. However, even if you are approaching a large vessel that is "dead in the water" or at anchor or even at dock there are still great dangers as to the placement of your vessel. If you decide to "come alongside" near the bow or front of the ship you may be directly below one of the ships massive anchors. The crew may not be aware of your presence and release the anchor, or the anchor holding mechanism could malfunction and drop this heavy anchor onto the deck of your small boat. This could "ruin your day" and your Department might then have to be in the market for a new fireboat.
Another danger along side of a large ship is indicated by the presence of a propeller shaped hull marking like the ones pictured on the left. These propeller shaped markings indicate "thrusters". Thrusters can be found at the bow and/or stern. They may be found as a single thruster or in groups as pictured left. The thrusters are underwater but the markings described will be located directly above each thruster on an above water section of the hull of the vessel.
Thrusters are in fact additional propellers to help maneuver the ship. These propellers are mounted in a shaft which travels thorough the vessel's hull from side to side. The propeller can be run in either direction in order to propel the vessel sideways in one direction or the other. If your small boat were alongside the ship in the vicinity when one these thrusters started it could create either a pushing or pulling current that could endanger your boat and its crew. The photo on the right shows the view looking into the tunnel thruster of a large ship. This tunnel was large enough for a man to stand up straight as he worked in this area. The thruster propeller can be seen midway through the thruster.
Another hull mark just forward of the thrusters on the above photo indicates that this ship has a Bulbous Bow, which is an underwater projection of the ship bow. This projection will actually help the vessel slice through the water more efficiently while traveling at cruising speed across the ocean. (USCG photo left.)
In fact, it is one of the largest contributors to ship resistance reduction and that will mean more speed and greater fuel economy. In the shipping industry both speed and fuel economy are considered crucial to the success of that business. Therefore the great expense of adding this feature to any new vessels and the greater expense of retrofitting existing vessels is considered a worthwhile expenditure.
But why does this concern fireboat and other small boat operators? If you are maneuvering your vessel in close proximity to the bow of a ship which has a Bulbous Bow you could inadvertently strike that underwater projection and damage the bottom of your vessel. Unless you are a tug boat assisting the larger vessel it is a good idea to keep away from the bow and stern of any ship.
If you are a fireboat you would generally only need to be near the middle of the vessel where its boarding ladders (accommodation ladders) are located. (Unless you were supplying water to the deck of the ship as is covered in our seminars). From here your firefighters would be able to board and their equipment may be able to be hoisted onto the main deck. Please just remember that you represent a little fly as compared with the colossal size of these ocean going behemoths. Use caution and common sense when it comes to placement of your vessel near this ship.
You Firefighters on an inland waterway can have your problems also. Even if your are only concerned with Tow Boats and Barges you may have to deal with the problems of displaced water. On smaller waterways the barge or vessels displacement can be vividly seen by the water level on the shore actually rising as the vessel comes by and then receding as it passes. This pushing and pulling can be so strong that it will even effect the barge or vessel that caused it. This phenomenon is known as "Bank Cushion or Bank Suction." (See photo left.) If it can effect a larger vessel you know that it can effect your smaller fireboat. Tow boat and ship captains know about these pushing and pulling forces and will at times actually use those same forces to their advantage when navigating bends in rivers. (Small boat operators must use caution when passing in these narrow waterways. (See our "Tow Boat and Barge Fire" seminar).
Here is a quote from a 2005 news story, "A tug's barge bumped with a 17-foot fishing vessel. The Coast Guard said the barge was restricted to the narrow channel and was coming down in the path of the fishing vessel. The operator of the fishing boat refused to move until the last minute, Coast Guard officials say. "When he did, he only moved just enough that he was not blocking the path of (the barge) but as (the barge) goes passing by, they actually create a suction, and it sucked his boat into the side of (the barge)," said Lt. j.g. Chandra Hartsfield, public affairs officer for U.S. Coast Guard Sector North Carolina." October 19,2005 BY JOE MILLER DAILY NEWS STAFF
Another problem involving operating around barges can be especially dangerous in the swift currents of some of our major inland commercial waterways, especially during flood stages. "Down-streaming" is a tricky maneuver employed by some tug and tow boat captains. It involves approaching a tow (barge or group of barges) from upstream with the current on your vessels stern and your bow headed downstream towards the tow. The approach is slowed and controlled by running the tow boat's engines in reverse to fight the current. Once the tow boat makes contact with the barge it is tied off and the tow is made up. Trouble can arise when either the engines are unable to counter the current or the current turns the tug so as to be "side to" the barge and pins the tug against the front of the barge. The swift current can now act to capsize the tow boat and pull it under. Again, if it can happen to a powerful tow boat, it can definitely happen to you in a small fireboat. If possible, do not approach a barge with a strong current on your stern. The best way to approach anything on the water, whenever possible, is by heading your vessel into the current. You will have much better control of your own vessel.
When I started writing this article I planned a short piece about the dangers of the "bow wake" that I mentioned in the first paragraph. The subject of small boat handling involving emergency and/or firefighting operations is one which could fill volumes, and I guess I got a little carried away.
I have been asked to set up a seminar to address some of the hazards and operating techniques of handling a fireboat responding and operating at fires and emergencies. This seminar will also address some of the "tricks of the trade" that can help you handle your fireboat in common tasks as well as in emergency situations. I am in the process of setting up such a seminar which will be added to Marine Firefighting Inc.'s other 24-hours of marine firefighting seminars hopefully sometime before the end of 2005. That is, "if I find that there is an interest out there". If you would be interest in such a seminar please let me know and also give me some specific areas of this topic that you would like to see addressed in such a seminar..
Update: As of February 2006 this new seminar has been completed and is available for the safety of your Fireboat crews. Please call or e-mail to set up a date for this training now. Further info available on our "Fires and Drills" page. Handling Small Fireboats
Please leave you comments about this article (Good or Bad) in my Guest Book. Or give me your comments about any future topics you would like to see. If you prefer, you can e-mail me by clicking on the letter to the right. MarineFires@aol.com
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