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04.06.2021 15:15:40
Sometime raft can be activated and board right onboard, then drop into the water by crane. But not in all ships. Once board, it’s your duty to help others to board as well. [links]
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Sometime raft can be activated and board right onboard, then drop into the water by crane. But not in all ships. Once board, it’s your duty to help others to board as well. [links]
In other to keep those working or traveling by sea safe, we share this useful information which might help in promoting the sea transport safety and make it more trusted.
The automatic mode of activation can be obtained when the ship sinks. With the help of HRU attached to the leashing connected close to cylinder rope joint, once HRU activates, it will cut the leashing rope, creating a chance for the water force to float up to the raft and activate. Ask officers onboard to show you the device. For HRU renewal and maintenance learn more from wartsila article about HRU usage here
Hopefully, this article explains better. But to add more or ask questions, feel free to drop your comment below.
4) Boarding the raft: It’s recommended not to board the raft with any shape object ( it will damage the raft). It can be board by jumping into the water and swim towards the raft, jump directly to the raft ( if no one inside). here
DITCH BAGS
If you want gear in your raft, and the raft doesn’t come with it, then you’ll want to make sure your ditch bag does. Five items that are a must include:
• An EPIRB (preferably) or a PLB.
• A watermaker like the Katadyn
Survivor 06.
• A waterproof handheld VHF radio
with extra batteries.
• Any prescription medicine that the
crew requires.
• A pair of cheap reading glasses.
The value of an EPIRB cannot be overemphasized. This single device will turn a life raft experience from a long, depressing test of survival, leading to the writing of a depressing book about how long it took to get rescued, to a breezy short story about the marvels of modern survival systems and the radios that make it all possible.
Ditch bags should float with all of the contents, should be of a bright color, have a lanyard so it can be attached to the life raft’s tether, and should be in a well known location on board the vessel. To hammer home the location of the life raft ditch bag, many skippers have their crews put their wallets and passports in the ditch bag along with the other gear. Not only is this helpful if you end up in a foreign country, but it ensures that everyone knows where it’s located. [links]
Life rafts are designed to keep the crew of a vessel alive for a short period of time after the vessel becomes uninhabitable due to fire or sinking. They provide a modest amount of shelter, equipment, hypothermia protection and a larger target for rescuers. In virtually all cases, a floating boat is a better choice than a life raft, so the decision to abandon ship must be made with great care after weighing the options.
LIFE RAFT EMERGENCY PACKS
Life rafts contain a distressingly modest amount of gear compared to what many raft survivors would have liked. This appears to be one of the great disconnects in expectations vs. reality, and for good reason. Most things in life are apparent and obvious: you can see and touch them and add to them if necessary. When you pack for a vacation, you know exactly what you’re carrying. A life raft emergency pack is different: it’s hidden from view, extremely space and cost constrained, and not visible until it’s too late to change it. In fact, life raft emergency packs can be added to when a life raft is being serviced, although the space is very tight, and some life raft repackers are not allowed to add items based on your specific type of raft and case.
The commonly supplied items are for the preservation of the raft, and not the crew. Common items include patch kits, leak stoppers (tapered rubber plugs that screw into holes in the fabric), raft repair clamps, topping-off pumps, bailers, paddles, sponges and overpressure valve plugs.
The next “level” up the survival chain generally includes some SOLAS flares (commonly three handheld and two rocket parachute flares), a fishing kit, a small medical kit, a signaling mirror, some sachets of water (125ml each, four per person), and seasickness pills. Take a look at the life raft manufacturer’s website or brochure to see exactly what’s included. Remember that many items will be due to a international standard as opposed to the whim of the life raft marketing team.
In Coast Guard and SOLAS rafts the inventory gets dramatically better, albeit heavier. More water, possibly some high calorie rations which do not require much water for digestion, a second drogue, and possibly some storage bags for all the gear.
What’s missing is vital: EPIRBs or other signaling electronics including a SART (Search And Rescue Transponder), a watermaker and a handheld VHF radio. And if you or anyone on your crew requires medicine on a regular basis to treat a chronic health condition, you had better carry it with you in the ditch bag because the life raft will surely not have it as standard equipment. here
STABILITY
Beside the considerable amount of weight, and therefore stability, of the occupants of a life raft, there are two design elements that determine whether a life raft capsizes in heavy seas: drogues and ballast systems.
Drogues are small drag devices that have several beneficial effects on the life raft. They reduce the rate of drift, so the raft stays closer to the position where the boat was abandoned. They orient the raft relative to the wind, so that the door or other openings can be aligned with the wind (or protected from the wind). They keep the upwind edge of the life raft on the water so that wind doesn’t get under the raft and help in capsizing it. Drogues can also be pulled from the water if it makes sense to increase the drift rate of the raft. This might be desirable if a vessel founders upwind of a shipping route, for example.
Ballast systems vary by type of raft, but generally consist of several large “bags” which hang below the floor of the raft. These fill with water soon after the raft is deployed. In other cases, the ballast system is a single large fabric structure that fills with water. Ballast systems increase the stability of the raft by adding peripheral weight to the raft floor, increase the stability by blocking wind that might get under the raft to capsize it and reduce the rate of wind drift due to the increased drag.
STOWAGE AND SERVICING
Raft manufacturers warranty most life rafts for 10 or 12 years, based on servicing according to their recommendations. In fact, a raft that is kept dry and is regularly repacked may last for 20 years or more until it is condemned by a factory-authorized service station. All of this depends to a large degree on whether the raft is damaged by water intrusion that leads to deterioration.
Many rafts are now vacuum-packed in sealed bags to prevent water from deteriorating the raft while in storage (presuming the bag remains intact.) Opinions vary as to the effectiveness of the vacuum packing, but virtually all experts believe that the quickest way to shorten the service life of a raft is to allow it to get wet and then leave the water in place. Fabric deterioration, metal corrosion, and seam failure can be the result.
Regardless of the type of raft, all rafts must be serviced according to the manufacturer’s recommendations by an authorized service station. And, if any raft is thought to have become “wet”, it should be serviced at the earliest practical time.
Although not common, there have been instances of inadequate servicing that have led to raft failures or raft theft (what was thought to be a raft turned out to be bricks and an old sail contained in a life raft canister). Since the only time you’re likely to need a life raft is when your life is threatened, you should “choose your raft repacker with the same care as you choose your family physician” in the words of the late Capt. John Bonds. An authorized repacker will invite you to see the raft when it’s in the process of being repacked so that you can see its features and understand what it contains, and what it does not. (For more on life raft repacking see page 46.) here
A study commissioned by the Australian government after the storm-swept Sydney-Hobart Race of 1998 further clarifies the hierarchy of life rafts in the eyes of experts. The commission recommended SOLAS-grade life rafts for future races. more
Modern inflatable life rafts are made of tough nylon fabrics that have been coated or “calendared” with natural or synthetic rubber to make them air tight. The tear strength of the material and seams are engineered to withstand impact loads associated with breaking seas and abrasion from curious sea creatures. The trade-off between weight and rugged reliability is a tough balancing act and good engineering is essential. more
Crew weakened by cold water and encumbered by the stress of a survival situation are often exhausted when it comes time to get into a life raft. This point was driven home during our wave pool tests in 2000 (Practical Sailor May 1, 2000 and June 1, 2000).
With a hydrostatic release, as the life raft and vessel submerge, the change in atmospheric pressure causes the release to fire, unlatching the canister from its cradle. As the uninflated life raft floats toward the surface, residual air in the canister and life raft oppose the pull of the sinking vessel to which the life raft may be tethered, creating enough tension in the painter to inflate the raft. While this auto-inflation scenario is plausible, we found that many uninflated life rafts don’t have a whole lot of buoyancy, and it is not impossible that a life raft could be dragged down with a sinking boat for some time before inflating, if it did at all. (After our test, Switlik said it was enlarging the MD-3 canister, which would add more buoyancy.) [links]
A raft’s drogue (called a “sea anchor” by some) is an important and often under-rated element in the stability and seaworthiness of all rafts. As a raft starts to come out of the water a drogue can provide significant added resistance to capsizing. For a square and especially a boat-shaped raft, however, it is more critical. A boat-shaped raft, running with wind and waves, is probably somewhat less likely to overturn, in this case end-over-end, than a comparably sized and ballasted round raft, all other things being equal (again, usually they are not). here
Canisters also present some other considerations. Good ones are heavy, adding weight to the often already heavy raft, complicating launching. Can you slide it under the lifelines or do you need to go over them? One Switlik canister we tested weighed 28.6 lbs. The rest of the canisters we deemed tough enough to survive on deck weighed in around 20-24 lbs. here
The weight and volume of the raft is affected by its capacity, its design, additional features, and the materials from which it is made. Other things also contribute to overall weight. A canister is generally heavier and more bulky than a valise. The selection of survival equipment also can make a huge difference in overall weight. here
In A Vacuum?
Vacuum packing, as used by Zodiac, West Marine, Crewsaver and Plastimo, can save money on initial services, which is appealing. It also does a better job of protecting the raft from the elements. Even many who don’t currently vacuum pack their rafts confided to us that they expect to eventually move in that direction. more