Vessel loading, stability and buoyancy

Transcript

[Music]

[Visual: A variety of boats moving across flat water, followed by a person fitting buoyancy.]

[Text on screen: Be Boatwise. There are NO second chances. Buoyancy. MAST logo]

[Visual: A boat named Monica being unloaded into the river. Andrew Hart, Hook Line and Sinker, talking to camera.]

Andrew: Today we are going to attempt to sink this boat Monika, not once, but twice it's going to be quite the operation with cranes and pumps and even divers.

The question is why are we going to do this? The answer could just save your life.

[Visual: Hardy and Crew loading Monica with safety equipment and fishing equipment.]

Andrew: Introducing Monica, she represents one of many vessels from her vintage which are available for sale on the side of the road or online.

At first glance she's actually fairly solid. Theres no rotting transom or gaping holes in her hull. Her engine doesn't run but with some work probably could. 

[Visual: Monica being towed away from the boat ramp.]

Andrew: Monica could get you out on the water, but will she get you home again if something goes wrong?

[Visual: Peter Hopkins, General Manager, Recreational Boating Safety & Facilities, MAST talking to camera.

Peter: What we're going to do today is, uh, test Monica for buoyancy. We rather think that being an older boat there won't be enough buoyancy in her, so we're going to put her on the bottom and then a little bit later on we're going to retrofit some buoyancy and just see the difference, because what we're finding is a lot of older boats in Tassie simply don't have the, uh, the buoyancy required. 

[Visual: Unfitted buoyancy blocks sitting in the boat, cutting to expanding foam being added to the hull of boat shell.]

Peter: Buoyancy will help keep the boat afloat and enable you to get to your safety gear in time and give you a chance to survival if you get swamped or capsized.

[Visual: Aerial view of Monica being towed.]

Andrew: Boats of Monica's age do not have an Australian Builder's plate, modern boats do

[Visual: Australian Builders Plates showing a boat’s details.]

Andrew: And that plate will tell you about the vessel and that it's fitted with enough buoyancy to keep it floating even when it fills up with water.

Today its required by boat builders, but in the 70s, 80s and even 90s it wasn't.

[Visual: Monica being towed, cutting to Andrew and Peter talking in the towing boat.]

Andrew: We are hypothesizing that Monica as you would purchase her now off Gumtree, or Marketplace, or something like that, she has no flotation fitted, extra flotation fitted.

Peter: No

Andrew: So, we're thinking that she will probably sink like a stone. 

Peter: I would I would imagine so, they might, you might get an air pocket up forward yeah, we'll just have to wait and see what happens but I'm pretty confident she'll go to the bottom. 

[Visual: A third boat pulls alongside Monica. The crew, including Brock Males, Owner Total Dive Solutions fit buoyancy blocks.]

Andrew: The first part of the experiment is to sink Monica with added flotation.

To do this the team went to work filling all the empty spaces with foam.

Brock: It's a closed cell polyethylene and um you want to have like a quarter at least in the forward half of the boat or up the bow and down low if you can and then wherever it is, you want to make sure that if the boat does sink it's not going to just float out and float away so it needs to be secured wherever you put it.

[Sound: A drill]

[Text on screen: Buoyancy Formula. Aluminium, GRP & Steel 1.2 x (MxK+F) / 1000-D. Timber 1.2 x F/1000 – D.  M = Hull and deck mass. K = Alum 0.62, GRP 0.375, Steel 0.87. F = mass of machinery and fittings. D = Density of buoyancy material (foam approx. 35kg/m3)

Andrew: On the MAST website you will find a more detailed formula, so you know exactly how much flotation you need to fit to your boat. 

Once the foam is fitted Monica is pushed out and her brave crew begin to take on water, because someone left the bung out.

[Visual: Hardy and the other crew member are standing in Monica watching the water come in. They are wearing lifejackets.]

Peter:  see how quickly that water is coming into the boat now. 

Andrew: So that's just from the bunghole? 

Peter: That's just from the bunghole so it's pretty amazing it doesn't take long. 

Andrew: And it’s amazing how quickly things escalate. 

[Visual: The crew member is bailing water, cutting to the boat filling and tipping.]

Peter: It's interesting now.

Andrew: Oh, that's it.

Peter: The starboard quarter is under. The boat's filling up.

Andrew: So are we saying that with flotation in the boat now that maybe all she sinks.

Peter: Well time will tell I wouldn't be surprised if she does capsize. 

Andrew: Yeah! 

Peter: If it does yeah! 

Andrew: She's going over there now.

Peter:  It's not going to sink. 

[Visual: The boat capsizes and the two crew manoeuvre their way to the top of the upturned boat. Avoiding the tangle of ropes in the water. One crew member holds an orange flare.]

Peter: So, in a real-life situation they would have let their EPIRB go by now as well, to alert the search and rescue people and hopefully Hardy got a call out on channel 16 with the VHF to alert that they're in trouble and maybe get a Mayday out.

Andrew: Although upside down with the added flotation fitted Monica floats.

Peter: The way that boat's floating too demonstrates the importance of distributing that buoyancy right throughout the boat. 

If you recall we put 50% of the buoyancy down aft to compensate for the weight of the motor and you can see what a great job that's doing. 

The boat's floating pretty level in the water although it's upside down but people can get out of the water and sit on top of it and you know maybe even if they had a mobile phone in a waterproof case they could they could make a phone call as well

[Visual: Peter talking to camera.]

Peter: So the distribution of the buoyancy is really, really important and that's quite evident that's been done properly in this situation because the boat is floating without the bow boating floating out of the water so this is just basic buoyancy but it's doing the job it's doing great job. 

Andrew: The salvage team quickly had Monica floating upright again with the use of a pump she was ready to go for the second part of this test, sinking her with no added flotation. 

[Visual: Peter and Andrew talking to each other, cutting to the buoyancy being removed.]

Andrew: Okay so buoyancy has been taken out of Monica we're going to fill her up again with water. I mean I think I know what's going to happen. 

[Sound: A drill.]

Peter: She’s going to sink. She’ll sink.

[Visual: The support boats watch the crew of Monica remove the bung and the crew member demonstrates bailing with an esky as the boat fills.]

Andrew: Once again, the crew are set adrift and water is quickly coming in. 

Peter: It's relatively calm in here too. You can imagine what would be happening if you're out in a seaway with it with a wind chop, it'll all be happening a lot quicker. There goes the boat. Two are out. 

[Visual: Monica’s crew enter the water as the boat sinks.]

Andrew: This time Monica goes not just upside down but starts sinking quickly. There is a small air pocket in the bow which keeps her afloat for a period but before long she's gone to the bottom leaving the crew nothing to hold on to and making a search and rescue all the more difficult.

[Visual: Monica’s crew are waving their arms trying to get attention.]

Peter: You can see these two life jackets not doing as they should be. The one with the foam life jacket on is struggling to stay afloat and keeping his head above water. 

The inflatable jacket would be far better with a crotch strap on it wouldn't be floating up like that and he'd be able to sit back and relax a little bit, relax as much as you can be in this sort of situation. 

[Visual: Hardy releases a handheld flare while floating.]

Peter: Now's the time you've got to be careful not to panic. 

You've got to get your breathing under control, and you've got to set yourself up for a rescue. 

[Visual: Peter talking to camera and cutting back to Monica’s crew in the water.]

It's so much easier for search and rescue people to find a boat if they've got a bigger search target on top of the water. 

If the boat has sunk all they're looking for is survivors who might only be wearing a life jacket and only with their head popping around the water. 

They might see the colour of the life jacket but certainly if there is a boat floating it's a bigger search target for the authorities. 

Andrew: So, remember if you own or are planning on buying an older boat make sure you check it's fitted with enough buoyancy to keep it afloat even when it's full of water.

[Visual: screens shots of the MAST website and images of closed cell foam.]

Andrew: You can calculate how much buoyancy is needed using a formula found on the MAST website. 

Buoyancy should be closed cell foam not polystyrene which soaks in the water and will suffer decay from fuel or other chemicals.

[Visual: Monica submerged and Andrew on the support boat.]

Peter: This demonstration really does point out that any bait built prior to 2006 that hasn't got an Australian builder’s plate fitted you really don't know how much buoyancy is in that particular boat so take heed of this video and consider retrofitting buoyancy in your boat.

It might just save your life.

[Music]

[Text on screen: MAST. Marine and Safety Tasmania. Making boating better.]

End of Transcript