The Davits at the Wrecksite

[Encyclopedia Titanica]

Did the crew try to work against the list by swinging the davits out to different degrees?... Titanica! Thu, 06 Jul 2023

The Davits at the Wrecksite

Did the crew try to work against the list by swinging the davits out to different degrees?

www.encyclopedia-titanica.org

 

[Samuel Halpern]

It is quite unfortunate how highly respected researchers can so easily become misinformed about what can be seen at the wreck site concerning the state of the davits. As so well pointed out by Ioannis in this article, the photographic evidence gathered from the site, once one knows what to look for, shows that almost all of the davits that were photographed had been fully swung out except those for boat No. 1 and 2, which were also used to launch the collapsible boats.

 

[Arun Vajpey]

Three questions:

This is a quote from IG's article, wherein he has himself quoted Sam.

To keep things from slipping, a rack (row of teeth) on the bottom of the davit frame meshes with teeth on the inner edge of the davit quadrant. The outer edge of the quadrant has a wider rim with no teeth. The weight of the boat acting on the davit arm forces the quadrant towards the centerline of the bottom of the davit frame, ensuring the teeth always mesh, and the arm stays locked at an angle that is determined by the position of the hub and screw block on the upper part of the frame.

So, in other words, was it always necessary to fully swing out the Welin Davit before attaching a lifeboat and loading it to stop things from slipping? If yes, it explains the reason why all of them were swung out, but if not, why did the crew not try to compensate for the list?

The next question (applicable only of the Welin Davit could be operated partially swung out, of course) is whether the angle of the davit had to be decided before they started loading the lifeboat with people? Would it have been very difficult and/or unsafe to try to do so during or after loading?

Finally, did the arm of the Welin Davit remain completely rigid always or was there any bending effect with a fully loaded lifeboat attached?

 

[marina_irc]

Arun, I also, as someone with less knowledge I am very interested in the answers to those questions, but I can provide the answer to the final question myself, also—

Deflection is a matter of certainty. It could be calculated precisely with the weight of the boat, the weight of the persons and fittings in the boat, and the dimensions and materials properties of the arm. I suspect it was insignificant but cannot be sure without that data; with those data I could calculate it myself.

 

[Arun Vajpey]

The way I was thinking was that davits on a lifeboat were seldom, if ever, used in a genuine rescue since for a given ship a serious accident requiring evacuation was very rare. But they did carry out lifeboat drills and such on a regular basis and assume that there would have been awareness about metal fatigue, which was first described by the German engineer Wilhelm Albert in 1837 by studying such effects on iron mining chains. That's why I asked whether the arm of the Welin Davit was completely rigid or whether there was some flexibility with a fully loaded lifeboat suspended from it.

I recall reading (I think it is in OASOG) that late in the sinking Mudoch ordered the davits of Lifeboat #1 (which had in itself left the ship over an hour earlier) 'cranked back' to facilitate attaching Collapsible A once it was brought down from the roof of the Captain's Quarters. Of course, they were unable to position #A to try it becuse of the port list of the ship and a funnel stay being in the way.

 

[Bob Read]

The way I was thinking was that davits on a lifeboat were seldom, if ever, used in a genuine rescue since for a given ship a serious accident requiring evacuation was very rare. But they did carry out lifeboat drills and such on a regular basis and assume that there would have been awareness about metal fatigue, which was first described by the German engineer Wilhelm Albert in 1837 by studying such effects on iron mining chains. That's why I asked whether the arm of the Welin Davit was completely rigid or whether there was some flexibility with a fully loaded lifeboat suspended from it.

I recall reading (I think it is in OASOG) that late in the sinking Mudoch ordered the davits of Lifeboat #1 (which had in itself left the ship over an hour earlier) 'cranked back' to facilitate attaching Collapsible A once it was brought down from the roof of the Captain's Quarters. Of course, they were unable to position #A to try it becuse of the port list of the ship and a funnel stay being in the way.

Arun: Lifeboat drills were really just crew musters since you wouldn’t lower a boat while the ship was underway. In Southampton they performed full lowering tests for the Board of Trade inspection but just with a minimal boat crew. The subject of full load tests before the disaster is rather murky. Post-disaster full load tests were a disaster themselves as I outline in this article I wrote: http://titanic-cad-plans.website/wp-content/uploads/2023/06/Davit-Failure-Article1.pdf

 

[Ioannis Georgiou]

Three questions:

This is a quote from IG's article, wherein he has himself quoted Sam.


So, in other words, was it always necessary to fully swing out the Welin Davit before attaching a lifeboat and loading it to stop things from slipping?

The davits were swung out together with the lifeboat attached.

 

[Samuel Halpern]

So, in other words, was it always necessary to fully swing out the Welin Davit before attaching a lifeboat and loading it to stop things from slipping?

Once a boat was attached, they could swing it out to whatever angle they liked. The point that was made in the article (and in the referenced Appendix in my article) is that the angle to which a davit was swung out as seen at the wreck could only be reliably determined by the position of the hub and screw block on the frame, not the photographed angle of the davit arm which easily could shift when the davit and frame was stripped off the deck. The position of the hub on the frame would not likely move, and that would be the true indicator as to how far a davit was swung out to at the time of the break up.

 

[Ioannis Georgiou]

As for the drills, the crew did had a drill every week which included also the lowering and rowing around of two lifeboats.
On Olympic this was done when the ship was in dock in New York. I have covered this and other drills in a article a few years ago. It's of course also here on ET.

The forgotten drills aboard Titanic

Were the lifeboats on the Titanic ever tested and her crew properly trained to lower them?

www.encyclopedia-titanica.org

 

[Arun Vajpey]

The point that was made in the article (and in the referenced Appendix in my article) is that the angle to which a davit was swung out as seen at the wreck could only be reliably determined by the position of the hub and screw block on the frame, not the photographed angle of the davit arm which easily could shift when the davit and frame was stripped off the deck. The position of the hub on the frame would not likely move, and that would be the true indicator as to how far a davit was swung out to at the time of the break up.

Thanks Sam. But would the positions of the hubs on frames of the aft davits still be unlikely to move given the catastrophic break-up of the Titanic on the surface, the destructive descent of the stern section and its heavy impact on the ocean floor?

 

[marina_irc]

The way I was thinking was that davits on a lifeboat were seldom, if ever, used in a genuine rescue since for a given ship a serious accident requiring evacuation was very rare. But they did carry out lifeboat drills and such on a regular basis and assume that there would have been awareness about metal fatigue, which was first described by the German engineer Wilhelm Albert in 1837 by studying such effects on iron mining chains. That's why I asked whether the arm of the Welin Davit was completely rigid or whether there was some flexibility with a fully loaded lifeboat suspended from it.

I recall reading (I think it is in OASOG) that late in the sinking Mudoch ordered the davits of Lifeboat #1 (which had in itself left the ship over an hour earlier) 'cranked back' to facilitate attaching Collapsible A once it was brought down from the roof of the Captain's Quarters. Of course, they were unable to position #A to try it becuse of the port list of the ship and a funnel stay being in the way.

Metal fatigue wouldn't be a issue, but there is some deflection in metals within the elastic zone. This is a function of the modulus of elasticity of the material. This is a simple cantilever beam deflection case, so, the exact dimensions of the davit arm, weight of the lifeboat, and type of steel used to build the davit arm allows for calculation at any angle; I don't believe metal fatigue would be an issue, no matter how heavily laden the lifeboat was the construction of the davits seems very unlikely to have caused a load, at any angle, which exceeded the elastic zone of the material.

 

[Arun Vajpey]

Once a boat was attached, they could swing it out to whatever angle they liked.

In that case, why didn't they try to compensate for the list? Lightoller is supposed to have gone to the extent of attaching Lifeboat #4 to the side of the ship with wire to compensate for the port list; would it not have been easier to adjust the angle of the davit to suit?

 

[Samuel Halpern]

But would the positions of the hubs on frames of the aft davits still be unlikely to move given the catastrophic break-up of the Titanic on the surface, the destructive descent of the stern section and its heavy impact on the ocean floor?

The screw block was moved by the worm gear arrangement, and it would not likely move unless the gear was rotated.

why didn't they try to compensate for the list? Lightoller is supposed to have gone to the extent of attaching Lifeboat #4 to the side of the ship with wire to compensate for the port list; would it not have been easier to adjust the angle of the davit to suit?

The boats were all swung out early on while the ship listing to starboard. Apparently the crew were more concerned in getting the people into the boats as quickly as possible and not concerned with getting them across the gap. Just look at what happened at boat No. 10 where they were chucking kids across a 2 to 3 foot gap.

 

[marina_irc]

The screw block was moved by the worm gear arrangement, and it would not likely move unless the gear was rotated.

The boats were all swung out early on while the ship listing to starboard. Apparently the crew were more concerned in getting the people into the boats as quickly as possible and not concerned with getting them across the gap. Just look at what happened at boat No. 10 where they were chucking kids across a 2 to 3 foot gap.

Might I suggest it was a manpower issue? The list was probably changing to some extent throughout the sinking, and I doubt precise calibration of the angle for the boats was something they'd want to waste time on when the sailors were in short supply already. The officers probably just judged the correct angle by visual approximation ("That looks good enough! Lower away!") and there were not enough personnel, not enough time to waste peoples' time with this. One can push back and argue that "perhaps easier loading would have in fact made the evacuation faster", but in the crisis that kind of thinking is not something humans do. After all, the aviation industry uses checklists for everything for a reason which was taught with blood, much like Titanic's sinking taught many lessons with blood.

 

[Samuel Halpern]

The officers probably just judged the correct angle by visual approximation ("That looks good enough! Lower away!")

I think the original order was more like, "swing out the boats." The AB's working the worm gears just turned them until the davit arms were all the way out, and then worked the falls to lower the boats to the level of deck for loading. Just speculating.