Help! Frozen Boat!

I've heard that as a reason for the Titanic sinking, crappy steel rivets that became brittle in the cold water, broke under stress and opened up like a zipper. I have a low tolerance for cold water too.

 

I can't imagine that the rivets would be any more brittle in 30 degree water than say 70 degree water. More likely the rivets were too soft since they had to have been peened over during construction. To peen steel it must be mild (low carbon), otherwise they couldn't have been peened over at all but would have shattered (or, if a bit too high in carbon would have be noticed breaking too often when being installed.
I could also be wrong, as I am not a metallurgist. These are just my immediate thoughts.

 

Actually, you both are right. The Titanic's rivets where of a considerably inferior material, which did become brittle in cold water. There were several reasons for the ultimate catastrophic series of failures that resulted in her loss, but the biggest culprit would likely be the cold water brittleness of both the steel alloy used in her hull plates and the iron rivets. It's been found both the steel and the rivets failed by catastrophic brittle explosion. This is party explained by the speed of the impact and the water temperature, but more so by the chemical composition of both materials. Normally, you can expect some brittle failure in high speed impacts, but not the zipper like destruction found on Titanic. Normally, you have some plastic deformation, then tearing, before the material just erupts on a cellular level. Not with the steel and rivets used on this ill fated ship. These literally just exploded when suddenly highly stressed, so huge sections of seam opened up to the sea in fractions of a second.

 

ya the Titanic is an interesting lessons in what can add up to disaster

had the ship not turned at all but instead struck head on it would likely have survived

the tradition at the time was to "hurry" through the bergs rather than slow down and the weather kinda ganged up on them as well

there was an exhibit of titanic stuff that came through the natural history museum a while ago that was fantastic

lots of things contributed to the tragedy but the rivets being of an inferior material than the hull platting was definitely one of them

 

. . . and now the Titanic is eaten by a bacteria . . . ?

rust-eating bacteria . . . (Daily Mail, 7th December 2010)

Cheers,
Angel

 

I don't think this is the case. At the speed she was traveling, she would have stuffed the bow past her fore mast, opening up enough compartments to flooding to sink her nearly as quickly. She would have flooded down both sides, maybe even sinking faster. I suspect damage back to the #6 hatch (at least, possibly as far back as the #5 hatch) and well past the 3rd class companionway stars would have quickly took her down.

No, the prudent skipper slowed and steered south, but with the recent advent of fast Atlantic transit, a complacency took hold of many skippers, particularly in light of the relatively trouble free transits that were occurring at the time. Several years of event free crossings and a belief that technology has made it so safe, that man was hardly required to helm the boat.

The rivets and the steel alloy where to blame for this level of damage from the impact. The steel didn't deform and fold, it shattered along the rivet lines and the rivets also didn't stretch and deform their heads, they just crumbled. Again, some of this was a result of the speed of the impact, but most of it was from the quality of both the sulfur laden, low carbon steel and the poorly made iron rivets.

 

well this got interesting quick

yes it was the rivets and the spacing of the rivets that did her in and yes another skipper on the same rout at aprox the same time did steer a different course and slow his speed but Titanic was on a maiden voyage and the captain had been instructed to try for a record passage.

I've read a number of times that the ship would likely have survived had it only hit head on rather than a glancing blow down the length of the side. Given how much I've read about Titanic I should have started a thread ages ago about it

cheers

ps
by the way Par its good to have you back
hope all is well for the holidays
B

 

That much ship at that speed hitting an object of such mass... not good at any angle.

-Tom

 

This new member never understood that he was getting a valid suggestion. He must have been desperate in this situation; it would have been difficult in such circumstances to clam down and check out Par’s somewhat cryptic post with a simple Google search. Some of us have been tempted to quit the forum at times. Nonetheless, 1 hour and 1 minute from first to last post must be an all time record that will certainly take some beating. Moving on ...

He’s gone now so we can’t help him, but it’s an interesting problem. First thing I would do would be to rescue the motor while the ice is thick enough, then unload the boat if it's not already done.

Bubbles are supposed to bring up warmer water but the effectiveness of that would depend on depth of water - if there’s deeper water further offshore the warm water would be out there - so bubbles might just reduce the buoyancy of the water and lower the boat more firmly onto the surrounding ice IMHO. I would think he’d want to raise it. It might be smart to buy a bag of water softener salt, dump it into the bilge water, wait for that to melt then pump it out. Then he could at least check for leaks; the boat would probably pop up all on its own if it still wanted to float. But then what? Still surrounded by ice - although he did note that he had been able to break it up to some extent.

But I really don’t know about this kind of problem. First thing I would do is ask the forum membership for advice. Er, yeah ...

I hope he was able to solve his problem.

 

I have been washing and breaking a lot of ice the last few days. Because of this thread, I have observed closely how it washes.
First, I was somewhat mistaken in that water movement alone would destroy the ice (afterall, haven't we all used frozen rivers as hiways?). I think enough movement eventually erodes it but an outboard on his skiff likely would take too long.
The mechanics of how the ice breaks from a stationary boat with a propwash are that wash gets on top of the ice and with a little time weighs the ice down until it catches full flow of the propwash. At this stage, the ice folds under itself and breaks in pans, size depending on how much thrust is applied. Eventually, with a gentle flow that does not get on top of the ice, it erodes, and I did this two days ago, with a near boatsized chunk one half boatlength back, breaking out and leaving a hole. How much flow and shaft downangle dictates how far back this hole forms. I had to, in four inches of sea-ice, break it manually for four feet behind the boat in order for the water to get on the ice and fold it under from the weight.
If ice gets under the main plane of ice and prevents water from weighing it down, the process is purely by erosion unless you can mechanically get something to dislodge it, rev up and blow the sheet away, of hit it with the boat.
Transom sterned, I can't back through more than an inch or two of soft sea-ice. Today, I nosed into some pans four to eight inches thick and was able to nibble away substantial leads Four inches is about the practicle limit for a boat of my size. Maneuverability is almost nil until a little room for movement is attained. Problem is, if you nibble two large of a chunk, the shape of the boat directs it righ back into the same slot it carved the last time. The key is to nudge gently, and break off small chunks, then wash them away until you have enough room to turn.



Those catamarans behind me tried to get out today and can really only go straight ahead, concentrating ice between the hulls and seemingly directing it at the drive units. I broke ice for the cats departing and returning, as they are near helpless in much ice.
Re: the frozen skiff, I now feel that I would get some salt around the outboard, get the outboard off and then worry about the boat. The ice won't hurt it unless a river or other boats or wind is pushing it around.

 

I wonder if an exhaust gas bubbler could be rigged to help melt off some ice

 

We could put a coil of tubing over a wood fire or some other CO2 source to pre-warm the air before it goes into the water, warming the ice and the globe at the same time, thus delaying the onset of the ice age.

 

Around here, we use boats until the ice is too thick... Its gives some added stress to boats that they're not originally intended for...

1; One earlier work mate, had a wooden boat, pine hull, thin ice... He later said that in his life time he'd never so far had experienced anything that cold, nor did he ever expect to experience or survive, anything that cold, at any stage, later in life... (An oak hull is safer in thin ice...)

2; A funny one; one I know had always had boats with outboards, in thin ice the propeller housing willl act as an "achor" in thin ice.. Well, on a sheer impulse, he bought himself a boat with waterjet, we were waiting on the quay/ boardwalk, a pretty high construction on piles in the water. Thin ice, near the shores, cold weather, no wind, a perfect day... He came at full throttle, towards us, then suddenly the ice was strong enough to carry.. Sea ice is pretty strong, in an elastic way. The boat had no "anchor" as a boat with an outboard engine would have had. He had a really convincing speed, when eventually sliding under the quay/ boardwalk, we heard him swearing and hitting almost every pile underneath... (shaken AND stirred, someone talked something about the last ball on a snooker table...).