Tuesday, March 29, 2011

Damage Control

Once upon a time I used to occasionally teach damage control at the Australian Maritime College, it was a fun course (except in winter, when it was cold...). We had an old ship set up with a series of rooms that could be slowly or quickly flooded through various cracks, splits and dodgy pipework, all under the control of a sadistic instructor such as myself... Like I said it was great fun, but I also learnt some bits and pieces from this, most of which I hope I will never have to use for real.

Picture this, a dark night, shall we add stormy? no that would be too dramatic... So a dark night, somewhere maybe a couple of hundred miles offshore, nice sailing, wind vane doing its thing, boat trucking along on a tight reach, and a cuppa hot chocolate keeping the hands toasty warm. You carefully scan the horizon, looking under the headsail, trying to use the edges of your vision, and to be methodical, nothing seen so back under the dodger to get warm again, before the next lookout in a few minutes... Suddenly without warning a loud bang and a shudder as the the vessel rides up something unseen, you curse.... !@#$%^ due to spilt hot chocolate scalding your hand...

Well I guess you know whats going to happen next don't you.. Yep, Sure enough water can be heard trickling from somewhere forward, on the leeward side  Quickly... the boat is sinking!!

Is everyone ok? well then wake up and put something warm on. This could be a long night...Turn on all the bilge pumps, and make sure they are working. Attend to any injury's - put burnt hand in cold water, at least you have a plentiful supply in the bilges. Now start hunting for the leak and grab your damage control kit, we have one of these handy don't we?

Snow Petrel's DC kit (with $1 tipshop bag)
Fortunately we do, our DC kit is conveniently stowed up forward and for our metal boat it includes :
  • Instruction sheet with layout of seacocks and reminders and prompts to suit our boat
  • Torches- A head torch is good, and a floating torch... well floats.
  • Small axe to smash out joinery, and shape wedges then hammer wedges home.
  • Softwood wedges and plugs of various shapes and sizes
  • A block of soft closed cell foam to initially stem the flow
  • Underwater epoxy putty, in small and big sizes, and other suitable goop's
  • Quicksetting underwater cement, Ideally in a bag (can be stuffed unto whole to stem water)
  • Hoseclamps and screw driver.
  • Bicycle Innertube to wrap around leaky pipe
  • If hull is foamed, a way to remove foam, like an old chisel.
  • A pair of gloves (winter grip gloves are ideal)
  • Mask and snorkel 
All these handy items are in a bag that can be carried to where it is needed.
    After you have narrowed the leak down to the locker under the forward double berth you quickly clear all the crap out from it - it's amazing how fast you can clear out a locker (but you try to keep it out of the water). You ask for a check on the bilge level... we're losing ! Maybe you should think about a Mayday or Pan Pan - and get those buckets working faster...

    The leak is a split on a weld line near a frame, the plating dented, but the frame didn't, tearing the plate in this area, it's not big, but boy the water is spraying in, it's a good job you have that diving mask to put on... Maybe we can heave to on the other tack to lift it abit higher and reduce the outside water pressure, the slower speed will also help and it will be more comfortable...

    Quickly you grab a wedge and split it into three smaller wedges with the axe to better fit the curved split. The first two wedges go in quickly and the last is slightly trimmed down to better fit the remaining part of the crack. With the last wedge tapped in the leak is considerably slowed. Phew.... But this no time to rest easy, while that adrenaline is still pumping lets check the rest of the boat, there may be another leak. We notice the pumps start gaining on the water..

    It is now under the floorboards and after unlocking them you inspect the bilge and check the strum boxes are clear. We had kept them locked down to stop them floating away, and to reduce the amount of debris reaching the bilge.

    After a few minutes you mix some underwater putty and press it around the edges of the swelling wedges, it reduces the flow to a trickle... well done, lets downgrade that mayday and get another cup of hot chocolate and try to calm down those shattered nerves. And a Securitie to alert other vessels of the submerged hazard might be in order..

    At no time did the water get near our abandon ship point (with the water somewhere around my knees on Snow Petrel) at this point our efforts would have shifted into getting ready to abandon the vessel.

    This situation is hypothetical, and I hope it stays this way. But having a damage control kit gives you plan to deal with a leak, part of it's function is obvious - to put all the gear you might need in a handy place, the other part is not at first so clear. This DC kit and the thought that went into compiling it has given you a plan, and having a plan has prevented panic (or at least controlled it)... Suddenly you know exactly what to do, having the DC kit and a plan gives you a focus that helps to prevent running around in circles shouting and screaming hysterically...

    Now I note you can buy some pretty good kits but if you buy one please make sure you have also put the thought into how to use it. Non metal boats need different DC kits to metal boats (you can work out the details), and the old fothering trick with stout tarp has actually worked perfectly for me in flat water, try it on a seacock or when you clean your speed/log paddlewheel if you have one (I don't). I think they are just one more spot to get a leak from.

    By the way, The only two times I have had water over the floorboards it turned out to be freshwater from the watertanks. Taste the water before you pump it out.

    What do you have in your DC kit, and have you ever needed to use one?



    PS - check your memory, what tack was the boat sailing on (on that dark night) before the impact, no cheating by re-reading above... thought about it yet.. well actually I didn't specify a tack but I did have one in my minds eye, I am curious to see if we are port or starboard brained. as part of a world first and highly scientific survey click below on:

    (A) for "in my minds eye the boat was on port tack"
    (B) for "in my minds eye the boat was on starboard tack"
    (C) for "we were running under twin headsails wern't we?"
    (D) for "what does port and starboard tack mean?"

    And as always you can click on liked to give me a warm fuzzy feeling of accomplishment (and to poke a stick in the eye of all those nasty english teachers who were most unimpressed with my writing)


    1. Ben, if it's cold enough for a cocoa-mug hand-warmer, I'm headed south. If it's that cold, I'm likely still in the westerlies. Means I'm reaching on the backside of a cold front on starboard tack wishing for port tack and iced green tea.

      Scribing-wise, you are lucky, I'm married to an English teacher

    2. Ben,
      One item (2 ea, different dia) in our DC kit is pump inflatable children's playground balls kept about 1/3 inflated. We protect them from puncture/chafe with heavy carpet scraps. They are essentially shoring/cribbing.

    3. Hi Chris, I like your logic on which tack. Funnily enough I was on the stb tack as well, but down here that means I am heading south to the cold... Suits me. I like the inflatable ball idea, is sounds ideal for a leak in locker or behind something like a fuel tank... was that your thinking? and I hope I haven't offended your wife :-> My dad is actually an English teacher (or was)...



    4. Ben, Offended my wife? It'll take a great deal more than that...

      Yes on the "ball." We have some spaces that I can get my hands into or the tools but not both. So, we decided on a pressure bandage.