Help Required: Is Venice or Triest the best location for a naval base?

[Rum Medeniyeti]

Hey I am working on a TL featuring a surviving Austro-Hungarian Empire. The POD is way back in the 1900s, but the help I require at this stage regards the post-1900 period.

In your opinion, is Venice or Triest the best location for a large Norfolk-like naval base in the WWII and post-WWII periods?

Ok, now, in my TL there might not be a WWII or it might be really different than OTL's WWII, but my question here is not really about events. What I'm speaking here of is ship size and traffic volume. So do you think that Venice or Triest would be the best locations to support a large modern naval base similar in size and scope with the US one at Norfolk in the 20th century?

There woud be both advantages and problems with both situations. The Triest area is mountainous and that might create problems both in terms of the location of a nearby naval air station and in terms of meteorological conditions that might affect air traffic; also concerning road and rail supply routes to the naval base. Also the urban areas themselves and the commercial ports occupy a large portion of the available land. Finally, the natural harbours of the Triest area are not very large in size. There is a good natural harbour between Triest and Muggia/Mulgs and also a smaller one in the north part of Triest but that's about it.
The advantage would be that the natural harbours of Triest are of really good quality being rather deep, i.e. heavy ships would be able to sail there without further development.

Venice has it's own problems though. Venice is closer to the border with Italy (which is not very friendly towards the Empire), which is on the River Po. Most of the Venetian Lagoon is really shallow so extensive work should be done for it to accomodate large battleships, cruisers, destroyers and aircraft carriers. A lot of water displacement (when large ships sail in the lagoon) can damage the historical buildings of Venice and the other historical cities of the lagoon and also upset the hydrological balance of the lagoon. Now, my naval base would be located on the southern tip of the litorale del Cavallino, the peninsula just north of the Lido inlet into the Lagoon, between Punta Sabbioni and the inlet. So that is some distance from Venice itself. However I still expect that large construction efforts would be required to reshape part of the lagoon in the 19th and eraly 20th century, probably on the scale of what was done by the Netherlands. So the disadvantages of Venice stem mainly from the hydrological conditions of the lagoon itself. The advantage that Venice has is that, once reshaped, it would make one hell of a harbour.

Now, reshaping the Venetian lagoon is nothing new. The Venetians themselves did it for naval and military purposes. However, I'm not sure how acqua alta ("high waters" - i.e. occasional flooding) events would play out if there is a Naval Base on the tip of the Cavallino peninsula. It's possible it would make any alt-MOSE Project (which is an effort to enlcose the lagoon when the high waters come, separating it from the Sea, just as the Dutch do) very difficult, because access to the base should be available at all times, so where would one place the enclosing barriers?

Frankly I am leaning towards th Venice option, meaning that I belive the Venetian lagoon could be safely reshaped and it would provide a better harbour, but I'm not sure on the technical details and other aspects. So who knows maybe Venice is too much work and Triest would be better after all.

So, what would you say, which one would make for a better location for a large naval base?

[Richter von Manthofen]

Triest and environs. = Expand on the existing base at POLA.

[Josephus]

What about Cattaro?

[Keb]

Originally Posted by Josephus

What about Cattaro?

Too far south and without too much territory backing it. Even if Montenegro is integrated into the Empire, it would be too far from the heart of the Empire to be truly practical.

I would ask what's wrong with Pola, considering it was the main naval base of the Empire (since the mid-19th century) and already had the infrastructure built by the 1900s (including an extensive network of fortifiactions and maintenance facilities for ships, as well as a shipyard), especially as it, not being a major commercial port, allows the military more-or-less free reign.

Though if it's between the two options, I'd say Triest, it's a major commercial port, part of the Empire for a long time, has it's own ship-building industries (2 of the 3 dreadnought slipways in the Empire were in Triest) and is closely linked with the core territories of the Empire, certainly more so than Venice.

[Arachnid]

Triest by a million miles with modern warships, Venice is too shallow and reshaping and it keeping it reshaped would be a constant money drain. Remember most naval bases are at peace most of the time and the more expensive your peacetime base is the fewer warships you'll have built and ready to fight come war.

[mowque]

Originally Posted by Arachnid

Triest by a million miles with modern warships, Venice is too shallow and reshaping and it keeping it reshaped would be a constant money drain. Remember most naval bases are at peace most of the time and the more expensive your peacetime base is the fewer warships you'll have built and ready to fight come war.

This sums up what I cam to say.

[SavoyTruffle]

Triest, both for the above reasons, and the fact that you'd want to keep military facilities and tourist destinations distinct from each other.

[Rum Medeniyeti]

In my TL, there most definitely are naval bases at Pola and Cattaro (and Triest), as well as near Fiume and in another location on the Dalmatian coast (as well as near Valona (OTL's Vlore), on territory belonging to the Aromanian Principality and the Hellenic State -- see map, and on the Ionian Islands which is an Austrian Kronreich, i.e. realm, used to be a colony).
But my question is about where should the main naval base of the Empire be located, i.e. the huge one.

Venice had a different history with the Empire than in OTL. It was for a long time it's ally, it integrated peacefully with it, and in 1848 when Lombardy rebelled, in TTL Manin's band fought for the Empire, not against it. (Lombardy eventually joined Italy, but it became part of the empire once again after an alt-WWII or whatever events happen in my TL insted of WWII -- haven't figured that one out yet).

So it seems that Triest or Pola might be the best options. However, the ah writer in me kind of likes the idea of grand scale reshaping of the Venetian Lagoon. But I am not sure what such reshaping would entail. I believe some would would need to be done early on in the 19th century for the ironclads, then later some more work for the dreadnaughts, then in early 20th century some more work for the really big ships.
Does anyone know (more or less) what technology was available at what time and what would such work entail. I mean the Dutch did modify heavily their shores but they mainly tried to keep water out not to dredge deeper canals to allow water in. At what point does such technology become available.

Hmmm I guess surely Triest would be a much easier option, but I would like to research the technological aspects of Venice nonetheless -- it surely wouldn't hurt to know. So, if any of you knows any of the practical details on this...

This is what I used to have in mind for Venice:


And here is a map of the Empire within Europe in 2012 AD:

[Color-Copycat]

I'm thinking Triest would be better simply by merit of not being built on marshland.

[Rum Medeniyeti]

Yeah, but doesn't marshland make the whole Venetian area more difficult to assault by land?

Also, I am under the impression that some areas in the Lagoon are not marshland. I believe that the Cavallino peninsula is not marshland, but I'm not sure.

[Kome]

Originally Posted by Rum Medeniyeti

Yeah, but doesn't marshland make the whole Venetian area more difficult to assault by land?

Also, I am under the impression that some areas in the Lagoon are not marshland. I believe that the Cavallino peninsula is not marshland, but I'm not sure.

Maybe, but also consider Venice's position also makes it rather easy to besiege and cut off from Austria-Hungary proper. The fleet isnt gonna be of any use if its mined, stuck in Venice and under daily bombardment.

Granted Trieste isnt exactly that much better but if the fleet was bottled up in Trieste they would be somewhat safer at least and have a land route for resupply.

[Herzen's love-child]

Not to mention, reshaping the Venetian Lagoon for a major Naval Base would be an environmental travesty of which I shudder to think. Granted, this might not be perceived as too big of an issue in the eyes of the 1st half of the 20th Century except by the Venetians themselves.

[BlondieBC]

Originally Posted by Rum Medeniyeti

Frankly I am leaning towards th Venice option, meaning that I belive the Venetian lagoon could be safely reshaped and it would provide a better harbour, but I'm not sure on the technical details and other aspects. So who knows maybe Venice is too much work and Triest would be better after all.

So, what would you say, which one would make for a better location for a large naval base?

Either one is plausible for a TL. And even if it proves to be a "mistake", it enriches the TL because it adds realism. You also seem to be assuming too much foresight. If the harbor is started in the 1860's, they will not be worried about "dreadnoughts", but sail and coastal ironclads. And spread over 50-90 years, I am not sure the cost of any single year is that bad. It can also give a nice chance to have some "naval funding crisis" over port improvements.

There can also be the part of regaining the tradition of the Venice navy.

As to the sinking, I am not sure that is an issue before 1950. In Modern times, Venice changed two practice that hurt badly. The pumped out ground water under the city, which made it sink. In prior centuries, they would periodically lift the paving stones and add more dirt to make up for some of the natural compaction. A lot of those basement shops and bars were not originally basements, but the original street level.

And with the wealth of the A-H and prestige of the Hapsburgs on the line, I bet solutions can be found, even if the two items above don't change.

[Rum Medeniyeti]

Originally Posted by BlondieBC

they will not be worried about "dreadnoughts"

Oh, they're not worried at that point, but I am

Originally Posted by BlondieBC

spread over 50-90 years, I am not sure the cost of any single year is that bad.

Exactly what I was thinking

Originally Posted by BlondieBC

There can also be the part of regaining the tradition of the Venice navy.

Actually, that didn't much go away. Austria has a colonial empire in my TL, which started pretty much during the War of the Spanish Succession, when it was Austrians and Venetians (istead of British and Dutch as per OTL) that captured Gibraltar. It goes from there. Austria acquires several colonies from Portugal after that war (in my TL Portugal ends up un the wrong [French] side), but they depend a lot on Venice to reach and exploit those colonies. Venice already depends on the Austrians for military protection from the land and. They also depend on each other economically. Eventually Venice is integrated into the Empire in the times of Napoleon. Again all this is just a sketch I haven't worked out most of the details yet.

Originally Posted by BlondieBC

As to the sinking, I am not sure that is an issue before 1950. In Modern times, Venice changed two practice that hurt badly. The pumped out ground water under the city, which made it sink. In prior centuries, they would periodically lift the paving stones and add more dirt to make up for some of the natural compaction. A lot of those basement shops and bars were not originally basements, but the original street level.

And with the wealth of the A-H and prestige of the Hapsburgs on the line, I bet solutions can be found, even if the two items above don't change.

I'm not sure I understood what you meant to say here. Did Venice started pumping out ground water in modern times and that hurt? If that's true do they still do this? I mean if the method used in prior centuries worked better, they should have probably stuck with it.
Also what is the second thing they did wrong?

Another thing: is it tgrue that Venice was periodically "re-built", meaning that when old houses were in too bad a shape they would be torn down and new houses would be built in the same places (but obviously at a raised level), but that this stopped once Venice declined economically in the 18th century? And that that's why there are mostly 17th century buildings in Old Venice?

[BlondieBC]

Originally Posted by Rum Medeniyeti

I'm not sure I understood what you meant to say here. Did Venice started pumping out ground water in modern times and that hurt? If that's true do they still do this? I mean if the method used in prior centuries worked better, they should have probably stuck with it.
Also what is the second thing they did wrong?

Another thing: is it tgrue that Venice was periodically "re-built", meaning that when old houses were in too bad a shape they would be torn down and new houses would be built in the same places (but obviously at a raised level), but that this stopped once Venice declined economically in the 18th century? And that that's why there are mostly 17th century buildings in Old Venice?

Yes, in modern times they used electric pumps to pull in water. While they may have done this in earlier times, either primitive wells or human/animal powered pumps don't move near the volume of water. You have to look up how Venice got its water in the 1700's, they might have even got the water from another location.

Second, they stopped adding dirt. Deep delta flood plains compact. Venice is likely sitting on thousand of feet of mud, and it will compact a few mm/cm each year. In the natural situation, river floods dump enough new silt to keep the ground level the same. At least on the streets in older days, the Venetians added dirt manually about once a generation to keep the roads at an adequate height above sea level. In modern times, they stopped this practice. So take San Marco Square, you have to go down steps into the cathedral. If we used the same solution today, we pull up the paving stones, add about 5 feet of dirt, redo the stairs down into the Cathedral, and relay the paving stones. These are fitted stones by design, not set masonry. For some reason I don't understand, they instead accept he seasonal flooding and have people walk on wood beams held up by stones.

Now this part is my impression. Almost all buildings in Venice were built between 1300 and 1800. The average building has sunk by one to two stories. For buildings in the middle of the town, the lifting the paving stones along with sump pumps would fix all issues. For buildings on the water, the appear to have converted the first story to a boat dock. I would presume if Richer, Venice would have built a lot more newer buildings along with used techniques to lift buildings on the water front. It might be using modern techniques to raise the buildings or it could be as low tech as filling in the lowest underwater story with dirt and stone, strengthening the walls, and then adding stories on the top of the building.

There are also some issues related to dredging the lagoon, but I don't remember the details.

BTW: Have you been to Venice? If you have not, what I am saying may not make sense and you may need to look at some pictures to understand what is happening. It may sound complicated and a lot of work, but adding 10 feet of dirt to each Island per 1000 years is not really that much work. And building modifications are not that hard/expensive, unless you don't deal with the problem for 200 years and declare everything historic.

[Rum Medeniyeti]

I've never been to Venice. I'm from Eastern EU and the list of European countries I've visited (both EU and non-EU) is long, but for some reason, I've never managed to add Italy to that list (yet). Somehow I end up in Turkey or Greece in the summer, and in Austria, Hungary or Poland during winter holidays.

But I am doing a lot of research for this timeline and yes I've looked and continue to be looking into these issues that Venice has and what could be used to alleviate them, as well as what could be done to place a major naval base there.

And I agree with you. In my TL Venice is not exactly the commercial hub it used to be during the Rennaisance, I believe that isn't really possible, even in my TL. But Venice is much richer in my TL and not dependent exclusively on tourism. There is some chemical industry, the glass industry is more developed and the shore part (Mestre, etc.) has even some conventional industry. In my TL, between the late 1860's and the late 1940's, Lombardy was lost to Italy (as mentioned, it rejoined the Empire after an alt-WWII), but the Venetian proveince continued to be a Crown Land of the Empire, so at least some industry probably was developed around Venice (obviously on the shore, not on the islands).
And perhaps more importantly, I expect that some civilian shipping (or even a lot of civilian shipping) develops and even thrives headquartered in the city, perhaps even on the islands.

And if a major Habsburg naval base would be located in the vicinity of Venice (and perhaps a Naval Air Station on the shore near Jesolo), that would also contribute to the local economy and to further diversify it.

And you are right, if a major K.u.K. Kriegsmarine Naval Base would be located in Venice's environs, the Empire would be very interested in the region and would pump funding into it. I would expect that the technologies you mentioned would be intensively used, with regard to the historic character of the city, but nevertheless with practical main objectives. I would also expect that with time more advanced technology would also be employed. As you've mentioned, the Habsburgs' prestige would be on the line; they'd think of something.

Maybe I'll be getting a bit controversial here (hopefully not), but I think Itally neglected a bit the city and they basically made their mind from the beginning that it would be a tourism centred city. I don't really blame them, as Venice's problems started a long time ago, and by the mid 19th century in OTL it wasn't the bustling commercial hub it used to be, but rather a declining provincial centre. But I envision that in my TL the city, while still losing some of it's importance, will have a different fate.

Of course the result would be that in my TL, there would be some further building done within the city after 1800. Some old buildings might be rebuilt, but many old buildings would be preserved and, as you've said, maybe further levels added to them as the older levels submerge. It would be a compromise between the historic character of the city and practicality. It would keep the city really alive without it loosing its charm.

As for the lagoon, I'm still not entirely sure what exactly reshaping might be needed, especially between the Cavallino peninsula and the Sant' Erasmo island, i.e. where the ships would enter the harbour on the tip of the Cavallino peninsula. That section of the lagoon should be really deep, so that even the cca. 100 000 long tons-displacing Sissi-class aircraft carriers would be able to enter.

These concers make me ponder whether locating the main naval base near Triest would be actually better. But then again, it would make more sense from the Habsburgs' point of view (as you've alluded) that in the age of sail they locate their main naval base near Venice, not foreseeing the problems that larger ships would entail. Then, over the next 200 years, they would slowly modify the lagoon, expanding it for larger and larger ships. Indeed, if you tried doing that today, in 7 or so years, it might seem a gargantuan effort. If you have to do it slowly over 60+ years, it might not be that difficult.

BTW: Are you from Italy?

[Gunnarnz]

Originally Posted by BlondieBC

Either one is plausible for a TL. And even if it proves to be a "mistake", it enriches the TL because it adds realism. You also seem to be assuming too much foresight. If the harbor is started in the 1860's, they will not be worried about "dreadnoughts", but sail and coastal ironclads. And spread over 50-90 years, I am not sure the cost of any single year is that bad. It can also give a nice chance to have some "naval funding crisis" over port improvements.

That's an excellent point. It's always nice to see timelines in which plausible mistakes are made for the best of reasons, as seen from the time. I strongly concur that realism would be well served by avoiding too much foresight on the part of the people involved.
That being said, I think Trieste is a slightly more plausible choice even with those considerations. Although I haven't looked into it in detail, there seems to be a definite trend for naval ships to displace more and more as time goes by. It wouldn't take a genius to notice that tendency, and decide that Trieste's deeper harbour would be better in an unknowable future simply on that basis.

[BlondieBC]

Originally Posted by Rum Medeniyeti

And if a major Habsburg naval base would be located in the vicinity of Venice (and perhaps a Naval Air Station on the shore near Jesolo), that would also contribute to the local economy and to further diversify it.

And you are right, if a major K.u.K. Kriegsmarine Naval Base would be located in Venice's environs, the Empire would be very interested in the region and would pump funding into it. I would expect that the technologies you mentioned would be intensively used, with regard to the historic character of the city, but nevertheless with practical main objectives. I would also expect that with time more advanced technology would also be employed. As you've mentioned, the Habsburgs' prestige would be on the line; they'd think of something.

Maybe I'll be getting a bit controversial here (hopefully not), but I think Itally neglected a bit the city and they basically made their mind from the beginning that it would be a tourism centred city. I don't really blame them, as Venice's problems started a long time ago, and by the mid 19th century in OTL it wasn't the bustling commercial hub it used to be, but rather a declining provincial centre. But I envision that in my TL the city, while still losing some of it's importance, will have a different fate.

Of course the result would be that in my TL, there would be some further building done within the city after 1800. Some old buildings might be rebuilt, but many old buildings would be preserved and, as you've said, maybe further levels added to them as the older levels submerge. It would be a compromise between the historic character of the city and practicality. It would keep the city really alive without it loosing its charm.

As for the lagoon, I'm still not entirely sure what exactly reshaping might be needed, especially between the Cavallino peninsula and the Sant' Erasmo island, i.e. where the ships would enter the harbour on the tip of the Cavallino peninsula. That section of the lagoon should be really deep, so that even the cca. 100 000 long tons-displacing Sissi-class aircraft carriers would be able to enter.


BTW: Are you from Italy?

No, from USA, but had week vacation in Italy.

The port of New Orleans is top 5 in world and has harder to solve mud/dredging issues. The USA has line with concrete the first 1200 miles of the Mississippi River. So what you want is doable, just higher cost option. Port of Venice is tiny compared to NO. Same with city. You are just locking in the A-H to a high port budget, when Trieste or Pola is cheaper. It is more do you want the high prestige, but high maintenance jaguar or do you want to own a boring toyota? Both get you there, one does it in style.

You should not feel bad on Italy. Italy neglected a lot of things over the years due to funding, wars and other issues. Rome allowed the Coliseum to fall apart, when it was not actually using it as a source of building materials. They built apartment around where the chariot races used to be. Mussolini tore down the streets heading towards St. Peters Square. Seriously, who beside Benny thinks Benny is better at architecture than Michelangelo? I am sure a lot of similar things were done in Venice. And it is also true that when capitals of great empires fall, they can't afford to maintain the monuments and capital city.

[Shevek23]

I think, aside from the dredging/civil engineering issues, you should consider the strategic ones.

I gather your POD was many centuries ago, so it isn't clear just how and when the Empire gets ahold of the eastern Adriatic shore. Whereas the Empire would have had some degree of grip on the Po Valley plains going back quite a long while, losing it only for a time during the formation of the Italian state. Given that you describe the big war that is a watershed in your timeline as a "World War II" type rather than WWI, I suppose the really big naval base had to be founded well before that. The question is, how long before?

If Venice were built up as the Empire's biggest port back in the age of sail, then strategic interests would favor it--at the time the Empire appears to be holding its hinterland indefinitely and has done so for many centuries, whereas perhaps (depending on parts of the story you haven't told us yet) many of the good ports in the region I will call for convenience "Yugoslavia" (after all it's a term that means "south Slavs," it doesn't have to refer to a political entity!) might have only been recently acquired, or perhaps still in Ottoman hands, and meanwhile more of the hinterland might still be Ottoman (or fiecely independent like Montenegro). The roads and the like connecting the eastern Adriatic to the heart of the empire might yet be poorly developed in the mid-19th century, with railroads just being conceived. Whereas Venice is an old ally in what appears to be firmly held Imperial territory.

Then things change; the Empire tightens its grip on the Eastern Adriatic, apparently, but loses it for a while in the Po Valley. (Given an Empire as strong as your map implies, I would have assumed they just kept northeast Italy all along, but you've said otherwise, so be it.) If Venice is not already the flagship Imperial port, it would be foolish to make it so at this point! But if it was already established, the Empire won't abandon it and will make a point of upgrading it, fortifying the hell out of it, and demonstrating capability of supplying the whole city by sea indefinitely. To do that of course they have to develop other ports--Trieste for the supplies, Pola for the naval backup.

Really it isn't clear why you want one big concentrated naval base, rather than developing every good port to the max and having many of them. I presume it's for the sheer glory? Glory as a motive points to Venice of course.

I don't think the Empire would belatedly redevelop Venice into the star port after apparently winning her WWII analog. Though that is not inconceivable--it could be they win the war with the Yugoslav ports mostly, but find that their fleet swells to a monstrous size with new classes of monster ship that challenge even the deep water eastern ports. In the postwar rundown, they do mothball or scrap a lot of their swollen fleet, but they want to keep a lot of it, including the big monster ships, and determine they need to expand their ports' total capacity. Then, with Pola and other eastern ports already developed to the max, someone gets the bright idea of a really high-tech, sweeping revamping of the Venetian harbors. The Empire having once again taken back the Po valley, they don't have to worry about access to hinterland or the danger of enemy land attack (unless the north Italians are very restive as they might be). So it's a gradiose post-war project.

I think that's kind of a dubious scenario though; I'd think that wherever they made the big port, they'd have it developed to the max before winning their big mid-20th century war, not after. And then the trouble with Venice is, it is isolated and under some threat of land attack from an obviously hostile Italy and friends. It would seem irrational to make it their star port during the period they didn't control the Po delta, so if you really really want it to be Venice, as you've made it evident you would much prefer, I suggest you have to have it established as the main HQ port before the Po Delta is lost to Italy. That means it would achieve this status in the mid-19th century or earlier, and it looks like it would coincide with Venice formally joining the Empire rather than merely being a close ally of it.

It might make sense as a political deal--in return for surrendering her formal sovereignty, Venice gets the guarantee she shall be the chief naval port of the Empire on the Med. The Empire can still build stuff at Pola and the like, but the facilities at Venice must always match or exceed any other port; the number of ships based there must be more than at any one other port; headquarters is located in Venice and not some other port--all by treaty.

So when it becomes difficult to maintain Venice's supreme status, both because of losing the back country to Italy and because modern ships need deeper and deeper harbors, Vienna must either break the treaty under which Venice, a loyal and economically valuable part of the Empire, joined voluntarily, or honor the treaty and make whatever investments she needs to to keep it their best port. The Hapsburgs evidently choose the latter option, and I guess it pays off in "WWII" when not only can they hold Venice against Italy, apparently they can use it as a jumping-off point to reconquer the lost North Italian territories.

Again after the war, maintaining and even further developing the harbor is less of a problem with the Empire's expanded borders. However I'd think by then they'd be a bit sobered by the cumulative costs of reengineering the lagoon and keeping it that way while protecting the city, and seek to develop the other available ports until they each very nearly match Venice, and keep Venice just one half-step ahead of the others after that.

[Detlef]

Originally Posted by Rum Medeniyeti

In my TL, there most definitely are naval bases at Pola and Cattaro (and Triest), as well as near Fiume and in another location on the Dalmatian coast (as well as near Valona (OTL's Vlore), on territory belonging to the Aromanian Principality and the Hellenic State -- see map, and on the Ionian Islands which is an Austrian Kronreich, i.e. realm, used to be a colony).
But my question is about where should the main naval base of the Empire be located, i.e. the huge one.

Venice had a different history with the Empire than in OTL. It was for a long time it's ally, it integrated peacefully with it, and in 1848 when Lombardy rebelled, in TTL Manin's band fought for the Empire, not against it. (Lombardy eventually joined Italy, but it became part of the empire once again after an alt-WWII or whatever events happen in my TL insted of WWII -- haven't figured that one out yet).

The different history of Venice here in this TL should change things for a time. If the Internet is to be believed up to 1848/49 Venice was the major naval base of the "Austrian-Venetian" navy.
Obviously in OTL that changed after the rebellion. And there were also efforts to make the navy less Venetian centric (officers and crew wise).

A Venice not revolting and staying a part of the Austrian Empire probably would lead Vienna to try and reward such loyalty. Pretty rare in those years. So major, maybe main naval base for now. The naval academy stays there. Things like that.

Things probably will change somewhat in the second half of the 19th century. With armored cruisers and pre-dreadnoughts in the late 19th century, dreadnoughts in the early 20th century. I think it will be too difficult and expensive to build the large shipyards needed for these ships in Venice. Not to mention the problems with transporting the building materials there. So the large shipyards for building naval ships probably will be build in Pola and Trieste like in OTL.

At first the finished ships might still get stationed in Venice.
But unless the Italians build a major naval base somewhere close to Venice, Venice as the main Austrian naval base (and at the end of the Adriatic Sea) doesn´t make that much sense in the early 20th century?
If the Italians follow OTL, their main naval bases will be Tarent and La Spezia.
In that case Pola (with the shipyards) as the main naval base with Cattaro maybe as the main forward naval base might make more sense? Closer to the Strait of Otranto.

So Venice over time might become more the "emotional" main naval base? Location of the naval academy. Birthplace of the Austrian navy? Base for torpedo boats and some pre-dreadnoughts in the early 20th century? But maybe not the main naval base in ship numbers any longer.

Originally Posted by Rum Medeniyeti

So it seems that Triest or Pola might be the best options. However, the ah writer in me kind of likes the idea of grand scale reshaping of the Venetian Lagoon. But I am not sure what such reshaping would entail. I believe some would would need to be done early on in the 19th century for the ironclads, then later some more work for the dreadnaughts, then in early 20th century some more work for the really big ships.
Does anyone know (more or less) what technology was available at what time and what would such work entail. I mean the Dutch did modify heavily their shores but they mainly tried to keep water out not to dredge deeper canals to allow water in. At what point does such technology become available.

Hmmm I guess surely Triest would be a much easier option, but I would like to research the technological aspects of Venice nonetheless -- it surely wouldn't hurt to know. So, if any of you knows any of the practical details on this...

Dredging itself isn´t the problem.
German ports like Luebeck had to deal with it since the 16th century.
Some of my old research from "1632" discussions:
(Apologies for my English from back then. )

In the 16th century Luebeck started to get problems with the ”new” bigger ships. Their depth below water was too much for the Trave river.
At the beginning of the 16th century cargo had to be off-loaded at Herrenwiek on smaller boats for transport up to Luebeck.
Accordingly in 1539 the town council released an edict that every testament had to include a clause to donate part of the heritage for the ”clean-up” of the river Trave.
In 1541 they were able to buy an ”excavator” on a ”Prahm” (raft, small boat) from Danzig for deepening the river Trave.

Apparently they were successful since in 1566 they could build a warship in Luebeck with a tonnage of 1600 tons. Quite a bit larger than ordinary merchant ships back then.

Hamburg at the river Elbe had a similar problem later on.
So dredging a deeper and wider canal wouldn´t be the problem. Especially once you can use steam engines to power the dredge in the second half of the 19th century.

However that leads to another problem.
Apparently the Venetians in the 15th and 16th century diverted the small rivers originally flowing into the Venetian Lagoon directly into the Adriatic Sea. Back then it made sense. The rivers transported silt, small stones and would have gradually turned the lagoon into marshland. Destroying the water obstacles protecting Venice.
That of course means there is no new silt to resupply the existing islands. So over centuries the tides have started to erode the islands. Venice was fortunate that the existing openings of the lagoon to the Adriatic Sea were relatively small so the losses per decade / century were relatively low.

If however you start large scale dredging for naval capital ships and large merchant ships you´ll accelerate that process. Something which happened in our TL too.
If you start dredging in the 1850s, followed by more dredging to keep up with the development of larger naval ships, I´d suspect you would detect more erosion than normal by 1900 at the latest or so?

And then you have three options:

1. Ignore it and watch the islands slowly getting smaller. Not a smart decision if you want loyal Venetians.
2. Re-direct the rivers and / or construct small ships to transport silt / sand / earth / small stones to counteract the erosion losses. Success is uncertain since you have no idea how the currents / tides interact. (I dump a load of earth, small stones on one side of an island. Will it stay there? Or will the currents / tides transport it to somewhere else? Where I don´t need it?)
3. Decide the expenses are just too large and relocate the main naval base to Pola. While still helping loyal Venice to counteract 500 years of erosion.

Option 3 seems to be the wisest choice.