Considerations about naval designs

fallsfromtrees wrote:It's all very well to use existing ship classes for the design of Charis destroyers, but so far as I have been able to find, none of the references give a range, and the 3500nm range for the hypothetical 1000 tonner had no justification for it. Do we have ranges for the Smith class or the Cassin class destroyers? I did note that the Cassin destroyers built the Bath Iron Works used triple expansion steam engines, and that they could take one screw out of service to improve cruising range, but no ranges were given in the articles I perused.

I said I'd used the Cassin as the inspiration for the design. The design was intentionally stripped down to the bare basics to try and get as much range out of the hull as possible. I chose the Cassin because she had triple expansion steam engines and displaced 1,000t normal displacement. I needed dimensions to estimate the range, and so I picked the closest vessel I could to the minimal specifications given upthread.

As far as the range I chose in the design having no basis, it has a basis in that given the specifications of the vessel, if you minimize everything else and maximize bunkers and engines, then yes, you can theoretically get that range. Is it a perfect system? No. Is it practical? I have no idea. I use a software program to design it, but I have no idea the exact calculations the program uses to determine the final statistics.

fallsfromtrees wrote:It's all very well to use existing ship classes for the design of Charis destroyers, but so far as I have been able to find, none of the references give a range, and the 3500nm range for the hypothetical 1000 tonner had no justification for it. Do we have ranges for the Smith class or the Cassin class destroyers? I did note that the Cassin destroyers built the Bath Iron Works used triple expansion steam engines, and that they could take one screw out of service to improve cruising range, but no ranges were given in the articles I perused.

I have been looking and have not found any source for the range of the warship classes. The 'thousand tonners' were listed as the first truely blue water capable destroyers. However a cruising range is not given with most classes listed.

fallsfromtrees wrote:

doug941 wrote: - SNIP -

The range of a warship would be dependent on several factors. Oil is more energy dense and does not require stokers. The engines themselves become important as well. From 0 to +/- 20 knots, triple expansion engines are more economical, from +/- 20 and up turbines are the way to go.

In this case we were discussing a triple expansion 25 knot destroyer, although with access to OWL, I would assume that Howsmyn and Sir Olyvr would build a steam turbine for a 25 knot destroyer, but perhaps not if the
expected cruising speed was to be about 15 knots - far better than any sailing ship on the planet, but more efficient for the reciprocating engine.

A turbine would be greatly more efficient however it is also a lot more complex. With a piston drive you can have some slop in your measurements and everything will still work. If the center of balance of a turbine is off the turbine will shake itself apart. This is going to require very strict quality control. This requires very precise standard units of measure for dimensions as well as weight.
You can build very accurate beam scales that require no electronics. In fact most are more accurate than electronic models, its just that electronics are faster at weighing. However you have to have a standard weight so all scales can be made accurate to that standard. This is no small thing. I am assuming since it hasn't been mentioned that there is no weight standard. Maybe a better way of putting it is that the weight standard is as loose as the measurement standards Howsmyn mentions in the books several times. But without a precise way to measure the weight of the turbine blades I wouldn't want to try and construct one. Triple Expansion engines will work great for the foreseeable future.

Jeroswen wrote:Maybe a better way of putting it is that the weight standard is as loose as the measurement standards Howsmyn mentions in the books several times. But without a precise way to measure the weight of the turbine blades I wouldn't want to try and construct one. Triple Expansion engines will work great for the foreseeable future.

I think Howsmyn has steam turbines. There's the section where Father Paitr suggests using air tools for an assembly line and Howsmyn notes that the ships went with reciprocating because cutting reduction gears was a "not yet we can't" sort of thing, but for powering big air compressors turbines would be better. Since we know the air-tool production lines have been built (the M96 rifles and the new cartridge pistols) I take this as an indication that stationary steam turbines exist.

fallsfromtrees wrote:It's all very well to use existing ship classes for the design of Charis destroyers, but so far as I have been able to find, none of the references give a range, and the 3500nm range for the hypothetical 1000 tonner had no justification for it. Do we have ranges for the Smith class or the Cassin class destroyers? I did note that the Cassin destroyers built the Bath Iron Works used triple expansion steam engines, and that they could take one screw out of service to improve cruising range, but no ranges were given in the articles I perused.

I found some information that should give an idea of actual ranges involved. The British "River" class destroyer:

Length: 221 ft
Beam: 23 ft 6 in
Draft: 7 ft 1 in
Displacement 544 short tons

Coal bunkerage: 95 tons
Range: 1620 nmi at 11knots

The American destroyers of this era had much more coal bunker space than their British counterparts.
The Truxton class destroyer for example was 100 tons lighter but carried 175 tons of coal.
The Smith Class is 902 tons full load and carries 298 tons of coal.

I would guess that most US destroyers had a range of at least 3500 nmi.

Jeroswen wrote:The American destroyers of this era had much more coal bunker space than their British counterparts.
The Truxton class destroyer for example was 100 tons lighter but carried 175 tons of coal.
The Smith Class is 902 tons full load and carries 298 tons of coal.

Why would the ICN want a destroyer? Those are (certainly in the days of coal!) a primarily defensive class to fend off the other fellow's torpedo boats.

In the absence of torpedo boats (or an enemy who can build a steam engine at all!) you don't need as much speed, and you can build larger cruisers so the natural hull speed is as high as you want to move the ship.

It's difficult to find a close historical example; something like second-class cruiser HMS Apollo (1891) might be headed in the right general direction, only with the better Delthak steam engines and oil-fired. (Remember that Safehold knots and historical knots are different!)

Though I still think the prospect of a fast passenger liner should be using up a lot of naval design thinking in the Empire of Charis; use the same sort of machinery as the King Haralds, a double-bottomed steel hull, oil-firing if you can get it, and there isn't much on safehold that could threaten it. Just the thing for sending irreplaceable prelates round the empire in, as well as economically beneficial.

Graydon wrote:

Jeroswen wrote:The American destroyers of this era had much more coal bunker space than their British counterparts.
The Truxton class destroyer for example was 100 tons lighter but carried 175 tons of coal.
The Smith Class is 902 tons full load and carries 298 tons of coal.

Why would the ICN want a destroyer? Those are (certainly in the days of coal!) a primarily defensive class to fend off the other fellow's torpedo boats.

In the absence of torpedo boats (or an enemy who can build a steam engine at all!) you don't need as much speed, and you can build larger cruisers so the natural hull speed is as high as you want to move the ship.

It's difficult to find a close historical example; something like second-class cruiser HMS Apollo (1891) might be headed in the right general direction, only with the better Delthak steam engines and oil-fired. (Remember that Safehold knots and historical knots are different!)

Though I still think the prospect of a fast passenger liner should be using up a lot of naval design thinking in the Empire of Charis; use the same sort of machinery as the King Haralds, a double-bottomed steel hull, oil-firing if you can get it, and there isn't much on safehold that could threaten it. Just the thing for sending irreplaceable prelates round the empire in, as well as economically beneficial.

There several reasons to have destroyers if the brass want to go that way. The first being while the original name of those ships was "Torpedo Boat DESTROYER," by the turn of the century destroyers had themselves become torpedo boats write large. Early Earth designs could be carried. Both the first Whitehead and Howell torpedoes are not in trouble with the Proscriptions, being compressed air and flywheel respectively. Second since the ICN is OFFICIALLY limited to line-of-sight communications or wyverns/pigeons, a ocean capable ship able to carry dispatches is called for.

Having some destroyers to carry dispatches isn't the same thing as building destroyers as the workhorse of the ICN. What is the ICN's primary responsibility? To defend Charisian shipping? I believe it is. Rock Point summed up that problem nicely. One either defends merchies against raiders or one destroys the raiders' bases.

The same logic applies until another navy arises that can project power beyond its own port. Until then it is more cost effective to have a fleet of ships capable of destroying the fortifications of any enemy port than to build shoals of small ships capable of defeating only technologically inferior ships. I don't see that dynamic changing much. The ICN will build the bulk of their ships to defeat the best shore bound weapons the mainland can come up with.

doug941 wrote:
There several reasons to have destroyers if the brass want to go that way. The first being while the original name of those ships was "Torpedo Boat DESTROYER," by the turn of the century destroyers had themselves become torpedo boats write large. Early Earth designs could be carried. Both the first Whitehead and Howell torpedoes are not in trouble with the Proscriptions, being compressed air and flywheel respectively. Second since the ICN is OFFICIALLY limited to line-of-sight communications or wyverns/pigeons, a ocean capable ship able to carry dispatches is called for.

PeterZ wrote:Having some destroyers to carry dispatches isn't the same thing as building destroyers as the workhorse of the ICN. What is the ICN's primary responsibility? To defend Charisian shipping? I believe it is. Rock Point summed up that problem nicely. One either defends merchies against raiders or one destroys the raiders' bases.

The same logic applies until another navy arises that can project power beyond its own port. Until then it is more cost effective to have a fleet of ships capable of destroying the fortifications of any enemy port than to build shoals of small ships capable of defeating only technologically inferior ships. I don't see that dynamic changing much. The ICN will build the bulk of their ships to defeat the best shore bound weapons the mainland can come up with.

doug941 wrote:
There several reasons to have destroyers if the brass want to go that way. The first being while the original name of those ships was "Torpedo Boat DESTROYER," by the turn of the century destroyers had themselves become torpedo boats write large. Early Earth designs could be carried. Both the first Whitehead and Howell torpedoes are not in trouble with the Proscriptions, being compressed air and flywheel respectively. Second since the ICN is OFFICIALLY limited to line-of-sight communications or wyverns/pigeons, a ocean capable ship able to carry dispatches is called for.

Not arguing that the ICN shouldn't have cruisers, they should. But for convoy escorts against the church's privateers, cruisers are the wrong answer. For the amount of materials, you can make one cruiser or several destroyers. Cruisers would be needed to go against the BASES, DDs to go against the SHIPS. As a Terran example, BB/CA distant escorts were used against the threat of the Tirpitz and Scharnhorst, destroyers against the U-boats. An ICN destroyer with 3-4" guns and possibly a couple of torps would eat a church privateer for breakfast.

Build steam merchant ships to out run the privateers. That solves that problem. Destroyers are good to fight other steam warships. At the moment there are no enemy warships that steam merchies can't out run. Which emphasizes the primary need for heavy cruisers and battleships to destroy fortified bases.

doug941 wrote:Not arguing that the ICN shouldn't have cruisers, they should. But for convoy escorts against the church's privateers, cruisers are the wrong answer. For the amount of materials, you can make one cruiser or several destroyers. Cruisers would be needed to go against the BASES, DDs to go against the SHIPS. As a Terran example, BB/CA distant escorts were used against the threat of the Tirpitz and Scharnhorst, destroyers against the U-boats. An ICN destroyer with 3-4" guns and possibly a couple of torps would eat a church privateer for breakfast.