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Old 11th September 2019, 11:52   #46
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by V.Narayan View Post
Oh God. For blokes like us this is orgasmic. By jove. I cant believe a ICE engine that dishes out 100,000+ horsepower. I thought that power range was only for turbines. And 160 gms/kw/hr of FE. what a marvel. Thank you for sharing.
Narayan Sir,
That engine alone consumes upto 250 mt of Heavy Fuel Oil per day.
I can only imagine the capacity of its bunker tanks.

These super containers usually do speeds of 20~22 knots per hour.
A master mariner can confirm this since I have not sailed on container vessels.
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Old 11th September 2019, 19:11   #47
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by Ithaca View Post
These super containers usually do speeds of 20~22 knots per hour.
Correct. 20 to 22 knots and in some cases 25 knots even is their sailing speed which means their top speed would be higher.
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Old 11th September 2019, 22:39   #48
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by srini1785 View Post
This was indeed an eye opener for me. I just have a few questions.

On the topic of engines.
Answers below

On the topic of ships.
Answers below.
On the topic of engines.

1. What type of fuel is used?. Special grade diesel or the automotive type?.

Marine fuels follow the ISO 8217 Bunker Fuel Standard
For sake of convenience I will only describe Heavy Fuel Oil & Marine Diesel Oil.
Nowadays we have vessels that use the boil-off from LNG which is burnt in the engine.
This is so far restricted to the LNG (Liquified Natural Gas) tankers only.

HFO - Heavy fuel oil is a residual fuel. This is the sludge that remains after oil is fractionated.
Fractionation is the process of distilling various types of oil from the top most grade to the worsening grades and Heavy fuel oil is the last grade.
Instead of dumping it, they blend it and sell it as marine fuel.
It is very cheap source of fuel for the maritime industry.
You could compare it to coal tar that is used on our roads.

MDO / MGO - Marine diesel oil or marine gas oil are blends of distillate oil.
These are expensive to use on a continuous basis as they sometimes can be as high as 8-10 times the cost of HFO per ton.

HFO is stored at 35-45 degrees Celsius in the bunker tank. Heated up to 98 degrees C to purify it in dedicated purifiers and injected into the main engine at roughly 130-140 degrees C depending on the viscosity required.

MDO/MGO does not require any heating and can be injected directly.

2. What type of vibration monitoring systems are used?
Frankly, Vibrations is a vast subject that I have very little knowledge of so will defer to more learned members to answer.
The main engine has dampeners that help in reducing first order and second order vibrations but apart from that I have no knowledge.

3. How are generators coupled to the engines and what power do they produce?.
Most conventional merchant ships will have three auxilliary engines that start on MDO and are changed over to HFO.
B&W Aux engines have special heating arrangements for the fuel valves so they can directly start on HFO.

The Aux Engine is directly coupled to an alternator which supplies power to the MCB & ECB via bus bar and air circuit breaker and this powers the electrical requirements of a ship.
At sea only one Aux Engine is required but at port or anchorage, two are usually in use.

Apart from the Aux Engines, each sea going vessel is mandated to have an Emergency Generator with two kinds of starting procedures and this will power the Emergency Switchboard incase of failure of the Aux engines.

Some ships have a shaft generator that is coupled to the main engine via the flywheel and as soon as the main engine reaches a determined RPM, the shaft generator is engaged and power produced.
The Aux engine is then shut off and kept on standby.

Some super tankers have a Turbo alternators.
Here steam is superheated in a superheater by the main engine exhaust and this steam will propel the Turbo alternator.
The Aux engine is then shut off and kept on standby.


On the topic of ships.

1. If there are no brakes, i guess a large enough anchor would do the job of marooning ( correct word?. ).

Correct term - mooring / anchoring.
The main engine itself is used as a brake on sea going ships.
For an ocean going vessel that has been steaming ahead at 13 knots per hour, even if the engine is stopped, it will still take roughly 3 to 4 nautical miles for a vessel to come to a full stop.
In case the vessel is still not able to stop, an astern (reverse) kick is called for and this behaves as a brake.
Using Ahead and Astern movements, the experienced master will position the vessel in a safe space and use the anchor the moor the vessel.
Anchor is only used to keep a vessel in place. Contrary to popular belief, it is not the anchor that keeps a vessel in place but it is the heavy chain accompanying the anchor and lying safely on the seabed that keeps a vessel in place.

2. Some large ships never get to the harbour i am told, how or what determines the depth of water a harbour should have to accommodate transfer of whatever these giants are carrying.

Every vessel is essentially a cube. Length x Beam (Breadth) x Draught (Height)
Draught is calculated till its keel - the backbone of a ship.
For a vessel in the water, this height is furthur split into air draught and underwater draught which is what is colloquially called draught.

Air draught is the portion of the vessel above the sea line till main deck.
Underwater draught or draught is what is submerged.

A loaded super tanker will have an underwater draught of about 15-18 meters. So the seabed should even at low tide be anything above its maximum underwater draught for a vessel to safely be anchored at a place.
Places like Kandla & Chittagong are notorious because there have been instances when the vessel has sat on the seabed during low tides.

How does the Captain know what is the available draught - He has an instrument that measures the underkeel clearance (UKC). This is logged by deck officers every hour - I may be wrong. This is done so that the vessel does not touch bottom.

So to answer your query, the underwater draught of a vessel informs the master where he can anchor a vessel.

This is one major reason JNPT at Navi Mumbai was made because container vessels did not have sufficient draught to enter Mumbai port.
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Old 15th September 2019, 07:09   #49
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by MJ@Mariner View Post
Prologue
Imagine riding a vehicle which can develop 25,000 horses of power! How would you feel? Imagine the engine......but this is my first post. Hope you all enjoyed it. Any comments for improving the post will be welcome and I apologize if I have made any mistake.

Wonderful thread MJ@Mariner, and I regret coming here late. But like the old adage, better late than never!

Earlier I've added my two cents worth of posts & photos on the subject, in different threads, not really to do with ships or mariners. Grateful thanks to you for starting this one. And what a relief to find so many members from the mariner’s fraternity!

The Mitsui car carriers (my last blue water tenure as C/E, ’98 to ’08) I was on, were usually powered by Mitsubishi 8UEC60LS 8-cyl engines, with bore stroke ratio of 3.83:1 (bore-600mm & stroke-2300mm). They were not the ultra long-stroke examples which came later, with ratios of 4:1 or higher. The claimed SFOC is 167 g/kwh as per the manual. And the output is 14160 kw /18981 hp at 100 rpm.

Due to the poor stowage factor in car carriers (wt of cargo / occupied volume), the vessels are relatively large, 198 m length, but have comparatively low tonnage – 56500grt /16957dwt only! Also, the draught is only 8.8m & the operating speed is 20 knots.

This link gives some idea about the general specs of these vessels: https://www.ship-technology.com/proj...ourageous_ace/

I retired from active blue water sailing in 2008 (having joined sea in 1974) & continued in off-shore vessels till 2015.
I'm attaching a couple of photos from my car carrier & off-shore days.

Man, Machine and Water - A brief introduction to Marine Engines-dscf0021.jpg

Man, Machine and Water - A brief introduction to Marine Engines-dscf0020.jpg

Man, Machine and Water - A brief introduction to Marine Engines-dscf0016.jpg

Man, Machine and Water - A brief introduction to Marine Engines-dsc00114.jpg

Man, Machine and Water - A brief introduction to Marine Engines-dsc01458.jpg

Man, Machine and Water - A brief introduction to Marine Engines-p2021023.jpg

Last edited by aah78 : 20th September 2019 at 19:14. Reason: Pictures inserted in-line.
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Old 15th September 2019, 13:41   #50
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by shashanka View Post
Wonderful thread MJ@Mariner, and I regret coming here late. But like the old adage, better late than never!

I'm attaching a couple of photos from my car carrier & off-shore days.
Dear Dolphin, Please share some more photos and anecdotes.-from, Raven
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Old 15th September 2019, 17:15   #51
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by Ithaca View Post
MDO / MGO - Marine diesel oil or marine gas oil are blends of distillate oil.
These are expensive to use on a continuous basis as they sometimes can be as high as 8-10 times the cost of HFO per ton.
Small nitpick sir. MGO is technically a distillate and not a blend.

Edit: Sorry. Misread your post. I confused it to be meaning that its a blend of residual and distillates. However MDO is a blend between gas oil and residual oil. No?

Last edited by aah78 : 20th September 2019 at 18:17. Reason: Quote trimmed.
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Old 15th September 2019, 18:08   #52
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by vibbs View Post
Small nitpick sir. MGO is technically a distillate and not a blend.

Edit: Sorry. Misread your post. I confused it to be meaning that its a blend of residual and distillates. However MDO is a blend between gas oil and residual oil. No?
Yes you are correct, Sir.

MGO is a distillate oil.
MDO is a blend of Gas oil & Residual oil.
The percentage of gas oil is more than the residual oil and due to its low viscosity, it does not require heating.

MGO usually is colourless but MDO is black.

Fuels are characterised as DMA, DMB, DMC & RM grades.

MGO is DMA grade.
MDO is DMB grade.
HFO will usually be RM grade.
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Old 19th September 2019, 08:33   #53
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by V.Narayan View Post
Dear Dolphin, Please share some more photos and anecdotes.-from, Raven
Har, har ! Truth be told, I've harboured a secret hope that I be reincarnated as a dolphin the next time - total freedom with the oceans as your backyard, next to man in cerebral abilities (again a school of thought says they maybe ahead in the game), and the only enemy, as per Peter Benchley's "Jaws", being the Great White!

Thanks, Narayan - I'd love to share experiences & photos on this great thread. The problem comes down to my photo records. I am a relative latecomer to digital photography - around 2001 or so. The photos prior to that were on film and today they are a sorry mess of congealed plastic! I did not have the good sense to take precautions to preserve them. And in any case my camera skills are as good as any duffer's, so what I do have gives nightmares to any decent shutterbug!

One somewhat unusual aside in my case has to do with my very first voyage - the M.V. "Sonavati", Scindia's small coastal vessel which sank in a cyclone off the coast of Vizag on 8th Dec 1973. I was the 5th Engr on board at the time and the youngest crew member by a couple of decades - I was 21 and the others were veterans in their 40's. The other youngster was the wireman (D'Silva if I remember correctly) who was my age & also making his first voyage. To cut to the chase - there were 38 crew members, out of which 33 survived. I was in the life boat with 22 others and all of us survived and were picked by the "Jala Moti" (also Scindia's vessel) on the 10th of Dec'73, 44 hours after "Sonavati" went down, some 300 miles off Vizag.

The other 15 crew members chose the life-raft - and 10 survived. The radio officer, Mr. Billimoria, had the most tragic death. On the second day - 9th Dec'73 - after the cyclone had passed, sharks attacked the L\raft. It is difficult to visualise the horror of the incident - suffice it to say that Billimoria was taken first & two others who apparently suffered heart attacks, were dragged away subsequently. One has to acknowledge the immense will to survive & the courage of the remaining 10 crew members on the L/raft. They were also rescued up by "Jala Moti" a few hours after she had rescued us.

I remained on leave for a few months after the disaster and joined back sometime in March '74. So I can say that my sea carrier proper started in '74, since my first voyage (on the "Sonavati") lasted barely 2 weeks.

There have been other near misses in the succeeding 40 years that I spent at sea, but those are other stories for another time!

Cheers,
Shashanka
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Old 19th September 2019, 09:13   #54
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by Ithaca View Post
Yes you are correct, Sir.
True.

Let me throw in another interesting mix.
How do you see the new VLSFO (0.5% oil) slotting in?
RMG/RMD/RMK/DF?

Million dollar question right in the run up to 2020 Global Sulpur cap?

Last edited by aah78 : 20th September 2019 at 18:18. Reason: Quote trimmed.
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Old 19th September 2019, 09:31   #55
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Re: Man, Machine and Water - A brief introduction to Marine Engines

^^^^^^
By Jove that is some unique experience. Thank you for sharing. Very sorry to hear of the tragedy that struck your crew mates. Does a life raft sit lower in the water than a life boat. Is that why the sharks could reach up and grab. So clearly there are many more anecdotes waiting to put forth.
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Old 19th September 2019, 09:41   #56
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by vibbs View Post
Let me throw in another interesting mix.
How do you see the new VLSFO (0.5% oil) slotting in?
RMG/RMD/RMK/DF?
Million dollar question right in the run up to 2020 Global Sulpur cap?
Here is what I was able to source online.

Quote:
To keep it simple, all the products could be called fuel oil, in line with the terminology in MARPOL Annex VI which calls all fuels for marine consumption ‘fuel oils’.

This way we are left with the following terminology:
RM: residual marine (fuel that needs heating)
DM: distillate marine (does not need heating)
FO: fuel oil
ULSFO RM: maximum 0.10% sulphur RM product
ULSFO DM: maximum 0.10% sulphur DM product
VLSFO RM: RM products that are above 0.10% but meeting a 0.50% sulphur limit
VLSFO DM: DM products that are above 0.10% but meeting a 0.50% sulphur limit

Of course, the grade names in the ISO 8217 table will still be used, such as the distillate grade names DMA (clear and bright MGO), DMB and DMC (marine diesel oil grades, not required to be clear and bright) and the usual heavy fuel oil grades, e.g. RMG 380.
Source: Fuel Grades


Also attached is the BP Updated technical guide
Attached Files
File Type: pdf BP marpol-technical-guide-sept-2018.pdf (557.4 KB, 154 views)
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Old 19th September 2019, 15:19   #57
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by srini1785 View Post
On the topic of ships.

1. If there are no brakes, i guess a large enough anchor would do the job of marooning ( correct word?. ).
2. Some large ships never get to the harbour i am told, how or what determines the depth of water a harbour should have to accommodate transfer of whatever these giants are carrying.
Aah! A topic I hold close to my heart. How did I miss this thread! I sailed for 21 years, from the age of 19. Last 10 years were spent on the most splendid and fascinating of ships - LNG Carriers. Unfortunately, due to an injury, my sea career has ended, and I will be taking up a job ashore shortly.

The engineers have shed light on the Marine engine. So I thought I will take up the navigation part, being a Master Mariner myself. Just to add to what Ithaca has mentioned before, LNG vessels are the only ships allowed to burn their cargo as fuel. We carry LNG at cryogenic temperatures, less than -160 degC. Normally around 140000 to 270000 CuM in dedicated tanks.

1. Anchors are used to hold the vessel in place in shallow waters, typically less than 100 m. In depths more than that, the amount of hydraulic power required to haul the anchor and the chain puts severe load on the windlass. A windlass is the machinery used to drop or retrieve an anchor. Popular bunkering (refuelling) and storing ports like Fujairah have depths in excess of 100 m at the designated Anchorage. Anchoring and picking up anchor has to be carefully planned. Care has to be taken to ensure the windlass cooling systems are in order so that you don't fry it.

Stoppage of the vessel with engines has been explained earlier by Bhpians Ithaca in an earlier post. In addition we do something called rudder cycling, swing the rudder to either side alternatively, to reduce the stopping distance further.

Anchors are used to stop the vessel only in a emergency, in shallow waters for obvious reasons, and that too, as a last ditch effort because of the momentum that these gigantic ships carry. In all probability, you will lose your anchor or you may have to release it.

Some smaller ships use their anchors to hold themselves in place while alongside a jetty, in addition to using mooring ropes.

Mooring is normally done with the help of tugs. Large vessels may use upto 4 or 5 tugs to assist in positioning the ship alongside a jetty. They are similar to aircraft tugs. Vessels are tied to the jetty with synthetic or wire ropes which are on mooring winches.

2. Ships can only approach ports which have enough navigable and deep enough waters for them to approach. When a ship moves through the water, she sinks even further due to a phenomenon called 'squatting'. This can increase the draft of the vessel by 1 to 1.5 metres. So, in addition to the draft of the vessel, squat, tidal height, swells, safety margins etc needs to be taken into account before a vessel is deemed safe to approach and moor at a particular port. Normally, ships only call ports where they can safely moor. In some places, this may not be possible. So something called lightering happens. The large vessel, called the Mother vessel, remains at anchor at a designated place and smaller vessels approach the mother vessel and take her cargo in parts further up and into the port. Either the mother vessel or the lightering or in some cases, both the vessels should have the gear to transfer the cargo. One of the most popular area where this happens is LOOP (Louisiana Offshore Oil Port) in the Gulf of Mexico. Large VLCCs (Very Large Crude Carriers) discharge regularly to smaller tankers which take the oil to ports up the Mississippi River.
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Old 20th September 2019, 07:05   #58
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by V.Narayan View Post
^^^^^^
By Jove that is some unique experience. Thank you for sharing. Very sorry to hear of the tragedy that struck your crew mates. Does a life raft sit lower in the water than a life boat. Is that why the sharks could reach up and grab. So clearly there are many more anecdotes waiting to put forth.
An inflatable life-raft is considered safer than the lifeboat since it is unsinkable - provided it is undamaged. In our case, we had seen the remaining crew members on board throw the life-raft overboard (from the fore part of the ship) and then jump in to the water after it. And we assumed that they would have a better chance of survival than us as we were in the life-boat. And with 25-30 foot waves slamming us from all directions, there was no question of approaching them & within minutes they were lost to sight. Soon after we saw the Sonavati go down bow first & disappear. If you can visualise, think of being thrown up on top of a hill one moment (with clear visibility for a fair distance) and then flung into a deep trough the next moment, with mountainous waves surrounding us. This would continue for the next four hours or so till nightfall (the Sonavati went down around 3pm) after which the seas started gradually calming down, the cyclone having passed.

What we did not know at the time was that the raft was already damaged with the crew members jumping into it from a height of 25 ft or so. The rubberised floor of the raft had been torn by the falling crew members (one can also assume that some sharp object carried by some crew member while jumping could cause the damage). So the 15 people in the raft were essentially hanging on to the safety ropes going round the inner periphery of the raft's inflated tyre, with their body's hanging well inside the water. And this is why the sharks could attack the next day.

Jala Moti landed us in Vizag the next day (the 11th Dec) and we were admitted to a hospital. The lifeboat survivors (the 23 of us) were discharged after first aid, since we were essentially in undamaged condition. But the raft survivors, who were in trauma, were under psychiatric care for some time.

Those 44 hours in the life-boat for us is a sort of surreal nostalgia - I remember the loud prayers of the crew (mostly Konkan Muslims) as they called out verses from the Quran/Koran. I too was babbling something or the other, I don't remember.

What I do remember is thinking, is this all there is to it? And I haven't even have had sex yet - that being the central theme in our lives at the time, prior to the disaster!
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Old 20th September 2019, 10:31   #59
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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Originally Posted by SCORPION View Post
Aah! A topic I hold close to my heart. How did I miss this thread! I sailed for 21 years, from the age of 19. Last 10 years were spent on the most splendid and fascinating of ships - LNG Carriers.
We carry LNG at cryogenic temperatures, less than -160 degC. Normally around 140000 to 270000 CuM in dedicated tanks.
@Scorpion.
A few queries as you have commanded LNG Vessels and I haven't sailed on LNG.

1. Does the cargo blowoff supplement another fuel source for the main engine.

2. Since the cargo blowoff is also used as fuel in the main engine, how do you account for the short cargo that has been consumed during voyage at discharge port.
Say the vessel has loaded 50,000 MT of cargo at Saudi and by the time you arrive at Singapore, you have consumed X MT of cargo in blowoff, how do you account for this shortfall of X MT.
Do the charter party terms define the amount of cargo blow off that can be consumed per day.

3. Is LNG one grade of gas or like LPG you have three or four types of cargoes that you can carry.
I did one LPG ship and we only carried Butane so there was not much to do in the ballast voyages except keeping the tanks cool.

Wishing you a speedy recovery and all the best in your hunt for the next assignment.
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Old 20th September 2019, 12:58   #60
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Re: Man, Machine and Water - A brief introduction to Marine Engines

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What we did not know at the time was that the raft was already damaged with the crew members jumping into it from a height of 25 ft or so.
That was quite the ordeal you and your crew mates went through. Fortunately, I never experienced anything like that during my merchant navy years.

Jumping into the lift raft is sort of natural thing for people to do. However, as your mates experienced, there is high risk of damaging the raft. Also, you might hurt yourself as there tends to be various metal objects (e.g. gas cylinder, box with supplies) stored in it as well. It looks inviting, sort of a springy cushion.

The only way to ensure people do not do is to ensure they get regular training in the use of rafts. Not just a bit of theory. But actually in a training facility where you can inflate the raft, though it in a pool and jump in. We did some training in a wave pool and it is not easy to climb in the raft in big waves. Can not image how it would be under real circumstances. You guys were sort of lucky with the weather and the sea temperature I guess.

Nice to see and hear the stories and the photographs, thanks for sharing.

Jeroen
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