Forecastle and Well Deck Hatches


Arun Vajpey

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I have read so many conflicting and in some cases contradictory statements about the hatch covers in the bow area that I do not know what to believe. So as to understand this issue correctly, I have asked a few questions and request specific answers please.
  • First off, what material were those hatch covers made out of?
  • Second, how deep did the holds underneath go? Did they extend all the way to Orlop deck or were there different levels?
  • Third, I have read that soon after the collision, the canvas cover over one of the hatches (I am not sure which) was tenting-up, indicating water entering the holds (which it did since the #1 and #2 holds flooded early). If this was the case, how was the displaced air getting past the closed hatch?
  • Fourth, was there any air left in either hold when the bow went under? If not, the scenario described by Paul Quinn in his book Titanic At Two am where he describes increased water pressure on the submerged bow eventually caused catastrophic failure of those hatch covers with consequent sudden flooding of the forward holds could not have occurred since they would have already been flooded to the top.
 

Jim Currie

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Hello Arun! I'll answer your questions if I can.

(1).. Hatch covers were made of portable oak boards about 2 feet wide and 8 feet long and not less than 2.5 inches thick. They were located between portable steel beams that spanned the hatch area. The whole was covered by three - one on the another - canvas tarpaulins. The tarps overlapped all round the hatch opening and were folded against the external coaming then held in place by wooden wedges.

(2).. If you click onto "Deck Plans" on the home page of this site, you will get a very good idea of the layout of the holds.

(3).. Not sure what Paul Quinn was describing. However, as the water entered the holds at lower levels, it would displace the air. The displaced air would be expelled through the hold ventilators. The hatch covers would also balloon due to the displaced air trying to get thought the spaced between the covered hatch boards. if the rate of flooding was too great for the ventilators, the hatch covers would eventually fail. However. Titanic's forward holds were divided into three vertical compartments... a lower hold and two tween-decks. The lower hold would fill first. Can't envisage Quinn's scenario. I imagine that the lower hatch covers would be overstowed with cargo
 

Arun Vajpey

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Thanks Jim. If I understand you correctly, when water entered the lowermost compartment of the hold, it would displace the air within through the hatch of cover of that compartment, right? But for the displaced air to balloon the tarps on the forecastle and well decks, the displaced air would have to first enter the middle compartment and then through another hatch to the topmost compartment and finally through the exposed deck hatches. Since air is compressible to a degree, would it have reached the outer hatch covers so quickly? Also, if the lower two hatch covers were overstowed with cargo, would it not hinder the passage of air to some extent?

Is there any way to calculate the time around which the forward holds, all 3 levels of them, flooded completely? If that had happened before the bow went under, would the water not have started to come out of the outer hatches and so visible to the crew in the vicinity?
 

Jim Currie

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Hello Arun.

All dry cargo holds in ships are ventilated. The ventilators reach to the uppermost exposed deck. For instance, when No1 Lower Hold started to flood, the air in that hold would escape via the vents. If the rate of displacement was too great, then air pressure would build a little under the hatch covers. However, I do not think they would fail until the hold was fully flooded and the outside sea level was rising above the level of the hatch cover. The water pressure on the underside of the hatch covers would thereafter increase by 64 lbs/ft for ever foot increase in outside water level above the internal hatch cover levels. Failure would then be inevitable and due entirely to internal water pressure on the underside of the hatch cover. This type of failure would be progressive.
You must keep in mind that hatch covers are designed to stop water entering the hold from above. The system I described to you worked very well. Very often, solid seas would be shipped inboard onto the hatch covers. Seldom, if ever did they allow water to get into the cargo.

Once the lower hold covers failed, the process would begin once more.

Cargo in the holds would have been tight stowed or tied-down. The water would simply flow round and over it unless it was extremely buoyant and had room to move. Cargo in a hold is a decided + during such a sinking process because it maintains displacement and at the same time reduces the amount of free air in the hold.

I think we can safely say that when the outside water level was about 2 feet above the top of the hatch boards in the uppermost tween deck of Hold 2, then all hatchway covers below that level would have failed. These would include Holds No.1, No.2, and the lower covers to the bunker hold and the baggage hold.
 

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