How many shipwrecks are there on the ocean floor?

[tdn]

@Philster

Wood does not rot under water.

Color me at least partly convinced.

A few years ago I was at a beach and a couple of kids asked me to try to lift something out of the water. I couldn’t. It was clearly a tree stump that was still firmly rooted in the sand. Considering that it was a good 30 feet offshore, and beach erosion doesn’t seem to be a huge problem there, and trees don’t normally grow in beach sand, I’d have to say that it was there for at least a hundred years.

[Alka_Seltzer]

@Qadgop_the_Mercotan

Color me unconvinced.

From a woodworking site: http://en.allexperts.com/q/Woodworking-2320/Wood-Rot.htm

As your quote says, if oxygen is absent the wood will not rot. That’s why wet wood buried in silt can last for a very long time.

[Qadgop_the_Mercotan]

@Alka_Seltzer

As your quote says, if oxygen is absent the wood will not rot. That’s why wet wood buried in silt can last for a very long time.

Yes, but I’m refuting the contention that “wood does not rot underwater”.

It certainly can, and often does rot underwater. It takes the circumstance of very low oxygen content to prevent it from rotting underwater. Having lived on a lake all my life, and having free and scuba-dived on wooden wrecks I’ve seen plenty of wood rotting underwater.

[obfusciatrist]

No insight on the answer, but to give a sense of scale, the book Shipwrecks of the Revolutionary and Napoleonic Eras lists more than 1,500 for just the 22 year period of 1793-1815 and the forward says this is just a fraction of the real total of 2000 per year worldwide during that period.

From 1793-1802 the Royal Navy (British) lost 162 ships to the sea (way more than the 62 lost to combat).

Also you have the issue of defining “ship” and “ocean floor.” When a surprise typhoon hits Osaka in 1862 and sinks 9000 vessels of various sizes in the harbor, do those count?

[DCnDC]

42?

[mlees]

Truk lagoon, Iron bottom Sound have many warship graves.

Wiki says the Battle of the Atlantic (1939-1945)

The outcome of the battle was a strategic victory for the Allies—the German blockade failed—but at great cost: 3,500 merchant ships and 175 warships were sunk for the loss of 783 U-boats.

Battle of the Atlantic (1914-1918)

Of the 12½ million tons of Allied shipping destroyed in World War I, over 8 million tons, two thirds of the total, had been sunk in the waters of the Atlantic war zone.[13] Of the 178 U-boats destroyed during the war, 153 had been from the Atlantic forces, 77 from the much larger High Seas Flotillas and 76 from the much smaller Flanders force.

US submarine campaign on Japan sunk thousands of ships.

One Japanese reference reports 15,518 civilian ships lost. JANAC reports 2,117 Japanese merchant ships lost with a total tonnage of 7,913,858 long tons (8,040,851 t) and 611 IJN ships lost with a total tonnage of 1,822,210 long tons (1,851,450 t).

“Millions” might not be far off…

[KarlGauss]

@RealityChuck

. . . there were probably hundreds, if not thousands, of shipwrecks each year during the age of sail, and the number didn’t drop until there was dependable weather forecasting.

I’m going to dispute this.

Weather forecasting would help, but I submit that more ships went down because of navigational error, e.g. running aground, getting ‘dashed’ upon reefs/rocks, etc. The importance of accurate navigation, or more specifically, the importance of being able to determine your longitude precisely (in the days of wind-powered boats), was wonderfully described in Dava Sobel’s Longitude. I cannot recommend it too highly (and, for those interested, please note that I linked to the so-called “illustrated version” which is visually stunning as an added bonus).

[sitchensis]

@tdn

Color me at least partly convinced.

A few years ago I was at a beach and a couple of kids asked me to try to lift something out of the water. I couldn’t. It was clearly a tree stump that was still firmly rooted in the sand. Considering that it was a good 30 feet offshore, and beach erosion doesn’t seem to be a huge problem there, and trees don’t normally grow in beach sand, I’d have to say that it was there for at least a hundred years.

Are you claiming that the tree you found lived its whole life where you found it and that the ocean level changed to put the stump under water?

[Boyo_Jim]

@Giles

I know of one fairly small area where there are the remains of 16 shipwrecks: Stockton Breakwater, at the entrance to Newcastle Harbour on the east coast of Australia. Here’s a picture of the Adolphe, the largest of those shipwrecks. Note that it’s not on the “ocean floor”: most shipwrecks happen on the coast or in shallow waters, where ships meet rocks, reefs or sand. In the Adolphe’s case, the ship didn’t sink very far, and a lot of the remains of the ship are above sea level.

Now you’ve done it. Some Hollywood type is going to see this and make an adventure film where the bad guy gets impaled at the end on one of those rusty sticking-up posts.

[Philster]

Wood can fall victim to critters on land and in the sea, but the point is that you can’t just jump in and go, “Awe, woods rots under water”.

Fact is, there are millions of tons of ‘preserved’ wood sitting in lakes, reservoirs and oceans. The water doesn’t just ‘rot’ them.

So, there are many preserved ship wrecks, because wood doesn’t just rot because it’s in water. Wood can be attacked on land and sea; it depends on what is preying on it. In many cases, it is much better off and highly – dare I say ***incredibly *** – desirable if it has been under the sea for many years – much more so than any landlubber wood.

.

[XT]

@Philster

Wood can fall victim to critters on land and in the sea, but the point is that you can’t just jump in and go, “Awe, woods rots under water”.

Fact is, there are millions of tons of ‘preserved’ wood sitting in lakes, reservoirs and oceans. The water doesn’t just ‘rot’ them.

So, there are many preserved ship wrecks, because wood doesn’t just rot because it’s in water. Wood can be attacked on land and sea; it depends on what is preying on it. In many cases, it is much better off and highly – dare I say ***incredibly *** – desirable if it has been under the sea for many years – much more so than any landlubber wood.

.

But it DOES rot under water, unless it’s in a very special oxygen free environment, or isn’t buried in the mud. In the great lakes at a certain depth you don’t see any life because there isn’t any oxygen. Same with the Black Sea. Same with the Baltic and parts of the ocean. But most of the ocean, and most fresh water lakes for that matter does team with life…and so any organic substance the isn’t in such a special environment or isnt buried in oxygen free/poor mud is going to rot, and fairly quickly.

-XT

[lawoot]

An interesting website - The Great Lakes Shipwreck File 1679 - 1998 (Compiled by David D. Swayze, of Lake Isabella, MI) lists all known wrecks JUST in the Great Lakes. The homepage has this note:

In my research I have found over 2500 vessels which were reported as total losses in the newspapers, yet lived to sail another day. However, if you have a good article which may report a total loss, send it along for comparison to my files. I have information on nearly 500 reported total losses which are not yet, in my estimation, well proved enough to go into this database (click here to see the list). Please note that this database is limited to vessels lost above the head of the St. Lawrence River (see note below), and, with a few exceptions, does not include yachts or abandoned vessels. Many wrecks which you may know about - especially those located in rivers or bays - were abandoned and are not in that spot because of a wreck.

Just under the letter “A” he lists almost 300 wrecks.

So that many, just in the Great Lakes in under 350 years- I can’t even begin to imagine how many worldwide for all time. I’d think over a million probably wouldn’t be an unfair guess.