HRU AND SLAMMING
In the seventies , around 400 bulk carriers sank. I was a junior officer those days.
In any other industry there would have been hell to pay. On a concorde aircraft if the passenger in the first class section spilt some wine ( because he was drunk ) on his suit, the next day many important powers would be personally apologising to him.
Sailors are expendable. Who cares? The persons ashore who are supposed to protect us , as busy saving their own chairs.
Theoretically 800 life rafts should have been floating for one month, having auto released themselves via the HRU.
Why did the 400 odd bulk carriers sink?
I have attended many seminars where the stupid speakers ( fresh water navigators all ) go on an on , about fast loading, bull dozers hitting hold bulkheads, grabs hitting coamings, waves washing away the hatch covers etc etc.
Nobody talks about slamming.
On the ballast passage if the Chief officer has NOT flooded the midship hold ( heavy weather ballast ), the bows will have less draft, and will slam.
When the ship slams , the whole ship flexes severely . The periodic motion is called springing.
When the ship's forward part takes off into the air and comes down crashing , microscopic cracks develop all over-- as welds are NOT elastic.
On the next iron ore passage , where the racking stresses are high and the ship is stiff, the ship sinks-- usually.
All bulk carrier men , place your hands on your hearts and tell yourself that you have always ballasted the midship hold in the ballast passage in rough weather-- you just cant-- don't even bother to lie to yourself.
When i was a Chief officer i had written to many classification societies, about having MINIMUM BOW HEIGHT endorsed in the stability books.
The master must not come under pressure from his chief engineer, to sacrifice bow height for propeller immersion. One compromises the other.
Why then did the life rafts not release as SOLAS meant.
Th reason is that all stupid training houses taught you to tie up the painter to a strong point on the ship. This was pounded into your head , right?
Now--when your ship is sinking and you are releasing the life raft manually, why should you bypass the critical safety devise , the HRU?
THE HRU IS THE STRONG POINT!
At least for the past 10 years , the shore training houses have got this right.
The weak link must part , by the pull of the INFLATED tent. When you throw the liferaft overboard and the while valise ( shell ) is towed behind for a while due to the ship's forward momentum, the pull must NOT come on the weak link.
Even today most of the HRU's are of very bad design. The most common one used the the west, uses a sharp blade to cut the painter--bwhen the HRU goes about 3 metres below the water.
Cut a tough painter, by constant sharp steel blade pressure ! right?!!! ( why don't you try this out manually! )
Why do we have "serrated" knives nowadays, even to cut soft bread or cabbage ?
Here is is true email I sent from one of my ships---
A05948 Fri, 25 Dec XXX 02:25
From: XXX - Master
Date: Friday, December 25, XXX 2:23 AM Msg: A05948-103541
Path: \XXX - Master\
Sub : XXX/ XXX MENTAL BLOCK
Attach: HRU MENTAL BLOCKS.pdf
XXX themselves have got their act together -- long after they came
into the market -- after a young ball of fire ( quenched few years ago )
personally blasted them --
for in the 70's hundreds of bulkcarrier with hundreds of lives lost --
twice that number of liferaft tents should have floated for atleast 30
days on the sea -- NONE EVER DID FLOAT --
on almost all ships initially the XXX HRU and others too -- was
connected wrong --
such a simple elementary condition-- YET-- all genuises get mental
why dont you take this small COMMONSENSE test yourself ? --
-- ( one hundred percent -- of 1st day on board cadets/ ordinary seamen
are supposed to know this )
1) ONLY THE INFLATED TENT BUOYANCY , WITH SHIP SUNK UNDER THE WATER
MUST BREAK THE WEAKLINK.--( this means ship is sunk )
2) THE UNINFLATED WHITE SHELL/ VALISE SHALL NOT BREAK THE WEAKLINK --
NOR EXERT PULL ON IT. ( this means that uninflated life raft is thrown
into ships wake with ship moving ahead with-- say--3 knots momentum and
windforce 10 waves battering the white egg shell )
3) THE PAINTER MUST BE TIED TO A STRONG POINT -- WHICH IS ON THE HRU
ITSELF--NOT SHIP'S STRUCTURE.
4) WHILE LAUNCHING MANUALLY --WITH PAINTER TIED TO THE STRONG POINT--
THE SAFETY OF HRU SHALL NOT BE BYPASSED ( CRITICAL PERIOD ).
HINTS : to convert 1% pass into 50% pass--
5) THE PAINTER SHALL NOT BE TIED TO THE "FIXED TO SHIP" PART OF HRU (
the part which sinks with ship to bottom of ocean ) .
6) THE WEAKLINK SHALL NOT BE TIED TO "FLOAT AWAY" PART OF HRU.( the
part which will be connected to floating liferaft tent with happy surviving sailors inside )
7) THERE HAS TO BE A FIRM HANDSHAKE BETWEEN THE PAINTER AND WEAKLINK --
TILL THE SHIP SINKS COUPLE OF BELOW THE SEA LEVEL -- AND THEY DECIDE TO
PART WAYS --
8) THE WEIGHT OF THE UNINFLATED LIFERAFT BEING TOWED IN THE WAKE OF THE
STOPPED SHIP WITH AHEAD MOMENTUM ( Item 2 ) SHALL BE FULLY TAKEN BY THE
PAINTER AND THE HRU.
found out what you are worth?
IF THE LIFE RAFT INFLATES ANY TIME DURING ADVERSE CONDITION NO 8 --
HAMMAR HRU CANT TAKE THE PULL STRAIN OF THE TENT -- THE PAINTER MUST
IMMEDIATELY BE TIED ON THE SHIPS STRUCTURE TO AVOID LOSING THE LIFERAFT
thanks and best regards
capt ajit vadakayil
" re-inventing team dynamics-- where time and energy is always made, for
things which matter "
CAPT AJIT VADAKAYIL