Where *did* the rest of the wreck go?

[elbowgeek]

Hi all, I'm a long time lurker but first time poster. I'm particularly interested in Spanish and other wrecks from before the 18th century and one thing which has intrigued me is the number of instances in which only on half of a ship has been located and excavated, but the rest of the ship (usually the stern half) remains undiscovered. This has happened enough times that I got to wondering if perhaps the ships of this period somehow have a structural weakness which predisposes them to breaking in half. The other half must float off pretty far if it remains lost. It has happened in one particularly famous wreck here in Bermuda which would very likely contain a great amount of treasure if found.

My only theory is that perhaps the lost half has managed to get so thoroughly pounded on the reef that there's nothing left of it, but that seems unlikely as there would be at least artifacts remaining if not wood. But it seems equally unlikely that, once a wooden ship has broken in two, one half is able to float long enough to be carried by the wind and waves very far.

Does anyone have any insight into this? I've been trying to find as many resources on pre-19th century shipbuilding techniques as possible, but they really don't tell me much about survivability of a hull after it's been pounded to pieces on reefs.

Cheers

Dennis

 

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[VOC]

There was not generally a weak point as such, but the sterncastle structure was obviusly the strongest part of the ship due to the amount of timber and the additional bulkheads, decks, and cabins etc.

Most ships that grounded by the bow might tend to break forward of the sterncastle allowing it to float free, and as it has more separate air spaces may allow it to float away some distance before it sinks.

The stern section also had less bulk cargo and less heavy guns etc. So not only does it let it float better there is also less to aid location.

 

[capt dom]

One of the structural weak points of 17th
century vessels what where there were cannon
ports.

The ribs of these vessels were massive.
My wife and I have gone to many shipyards in Europe
and here in the states where faithful re-creations of caravels.
naos, and east indiamen type vessels of 17th century vintage
have been re-constructed. We also have gone to Stockholm
where the Vasa a genuine 17th century flagship is on display.

Where the cannons stuck through the port and starboard hulls
of these type vessels were their weak points. See the computer generated
drawing my wife did below:

We (Jupiter Coins) think our ship may have dropped her bottom when impacting a
"Step in shore reef". We may be wrong but until we
test our hypothesis this is the direction we are moving forward.

The other photo is of me sitting in the poop deck of one
of these re-creations, the "Batavia" in Holland.

One thing for sure, these vessels sure had a lot of parts!

 

[cornelis 816]

Dennis . Look at it this way : The stern of the ship was 1/3 ( or a little less ) of the total length of the ship . The hold , say 2/3 of the ship , was ballasted and was also loaded with heavy cargoes . The stern had quite a boyancy capacity . It was high and constructed like the rest of the ship out of heavy timbers . Now when a ship was wrecked the cargo section sunk quite rapidly while the stern section had a tendency to stay afloat . The difference betweeb the two forces was usually enough for the stern section th sheer off . While the cargo section sank directly downward , the stern section altough underwater ( barely ) became subjected to the current that was flowing at that time . You may say what about the wind . Well , the wind had lost its grip on the stern because the biggest part of the Stern ( if not all of it ) was underwater . So thinking of the Maravilla we should change our thinking of the resting place of the stern castle . At the time of sinking the current flowed Northward while the winds were blowing Southward . If the current got a hold of the stern ( contrary to the beginning when the wind had a grip on the ship ) , the stern should have been floating toward the North with the current . We should therefor start looking to a resting place toward the North in deeper water . Just my way of thinking . Cornelius

 

[elbowgeek]

Thanks for the insight. And now I take a better look at the various drawings from the period I can see they have some crude bulkheads which I h adn't looked for before. The question then remains: How far could a sterncastle float once free of the rest of the ship? Someone we're working with seems to think it could be a few miles, but that seems a bit of a stretch.

Cheers

 

[elbowgeek]

We (Jupiter Coins) think our ship may have dropped her bottom when impacting a
"Step in shore reef". We may be wrong but until we
test our hypothesis this is the direction we are moving forward.

The other photo is of me sitting in the poop deck of one
of these re-creations, the "Batavia" in Holland.

One thing for sure, these vessels sure had a lot of parts!

That CG drawing is great, and it gives us something to think about when we do our searches.

Thanks

 

[elbowgeek]

Dennis . Look at it this way : The stern of the ship was 1/3 ( or a little less ) of the total length of the ship . The hold , say 2/3 of the ship , was ballasted and was also loaded with heavy cargoes .

Thanks, that makes a lot of sense. I think it's time to study the tides a lot more closely then.

Cheers

 

[cornelis 816]

The tides and current should always be taken in consideration . As far as a stercastle could float ? Why would it sink after a few miles ? There was enough timber there to keep her afloat for quite a distance . If she was destructed by waves she may drop her cargo on the way and the loose parts and timbers would just float on . There is no reason for her to sink . Beams may be found on distant beaches . The cargo ( coins ) would form a trail starting not too far from the wrecksite ( but not too close either ! ) . It is all common reasoning , Cornelius

 

[capt dom]

I must explain one thing - later mid 17th century caravelles
and smaller sailing craft plying the trade routes of the carribiean
had much smaller stern castles.

I am in no way disagreeing with any of others assessments and
in point-of-fact in our drawing the stern castle if the vessel had one
may have well broke away.

Shipwrecks in high energy surf zones are indeed catastrophic events
Lots of different things can happen as there is nothing bigger and more
powerful than a nasty sea... that is that you can touch!

Here is a painting of a ship about to lose its stern castle

 

[elbowgeek]

The tides and current should always be taken in consideration . As far as a stercastle could float ? Why would it sink after a few miles ? There was enough timber there to keep her afloat for quite a distance . If she was destructed by waves she may drop her cargo on the way and the loose parts and timbers would just float on . There is no reason for her to sink . Beams may be found on distant beaches . The cargo ( coins ) would form a trail starting not too far from the wrecksite ( but not too close either ! ) . It is all common reasoning , Cornelius

Points well taken. Currents will now be studied in detail, although I imagine those do change depending on the time of year.

 

[ivan salis]

once broken away from the rest of a ship --the stern in many cases might roll upwards in a sort of U shape due to most of the weight of the stern being at the very back of the stern * floating along like this --it might float a fair bit before sinking .

 

[capt dom]

Here is an interior shot of the rear inside
of the stern castle "poop"!

Notice I had good reading material!

 

[elbowgeek]

Fantastic, thanks :-) Looks like you would have had a great view as well *grin*.

Cheers

 

[cornelis 816]

Elbowgeek . That is why it is so important to know ( if at all possible ) the date of wrecking . Dave Horner gave enough clues in his book ( ,, Shipwreck,, ) to make a sound decission about theMaravilla . Cornelius

 

[elbowgeek]

Elbowgeek . That is why it is so important to know ( if at all possible ) the date of wrecking . Dave Horner gave enough clues in his book ( ,, Shipwreck,, ) to make a sound decission about theMaravilla . Cornelius

Indeed. Some of the wrecks we're going to be looking for don't have definite years of sinking, but many do. That will indeed be a challenge though.

I'm also searching for a particular English nautical map from 1740 which apparently marks several wrecks around the island, and it sounds like they have some measure of accuracy.

Cheers

 

[capt dom]

As we have gotten on subject of stern castles here is
another good photo of one and then one more photo
of the massive construction of ribs around cannon ports.

 

[VOC]

Elbowgeek, Have you talked to Teddy Tucker about your thoughts ? he may have spent some time looking for the same wrecks and may save you a lot of time.

Going back to your sterncastle thoughts, I once talked to some guys who wrecked a large timber trawler that had been converted to a sailing ship for a film that then then blew up on the beach, before they could clear the beach the tide beat them and large sections of the vessel drifted off on the high water. Apart from the shipping caos it caused large sections eventually came ashore up to 30 miles away down the coast.

I have seen a large sailing vessel that following the day of the sinking had floating debris over a area of 12 miles (app six miles each side of sinking on two compleate tidal cycles, so if the rest of the wreck is not close by it could be anywhere but as Cornelius says its best to start looking down tide from time of sinking.

 

[wwwtimmcp]

try not to think of the stern as floating but semi submerged with decks awash. it aint touching bottom so it is still moving until it reaches negative bouyancy. I just read a book about the divers that found the carl d. bradley, it snapped in half during a storm. the stern with engines running rammed the forecastle and made 5 miles before sinking. this was a steel vessel so imagine a wooden vessel with more bouyancy.

 

[Salvor6]

Dennis each wreck has different dynamics. It depends on the circumstances. You can't generalize a senario for every circumstance. For example the 1715 fleet ran into the shore and some of the vessels sheared off at the deck line. Another example, the Atocha sank in 55' deep water, upright and then another storm sheared the sterncastle off. It drifted over 10 miles, spilling treasure along the way and they still have notm found it. Every wreck is different.

 

[elbowgeek]

Dennis each wreck has different dynamics. It depends on the circumstances. You can't generalize a senario for every circumstance. For example the 1715 fleet ran into the shore and some of the vessels sheared off at the deck line. Another example, the Atocha sank in 55' deep water, upright and then another storm sheared the sterncastle off. It drifted over 10 miles, spilling treasure along the way and they still have notm found it. Every wreck is different.

That's what I figured. Thanks for the insight.

Cheers