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[size=3]T-21 Sphinx Class, Greek Torpedo Boat laid down 1926[/size]



Following the T-13 Series of eight ships (armoured torpedo boats in two squadrons of four) this is a new series with less delicate engines and heavier firepower in both guns and torpedoes.

Displacement:
602 t light; 621 t standard; 651 t normal; 674 t full load

Dimensions: Length overall / water x beam x draught
231.92 ft / 230.00 ft x 22.50 ft x 11.00 ft (normal load)
70.69 m / 70.10 m x 6.86 m x 3.35 m

Armament:
2 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1926 Model
Quick firing guns in deck mounts
on centreline, all aft, all raised mounts - superfiring
8 - 1.57" / 40.0 mm guns in single mounts, 1.95lbs / 0.89kg shells, 1926 Model
Breech loading guns in deck mounts
on centreline, evenly spread, all raised mounts
4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1926 Model
Breech loading guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 80 lbs / 36 kg
Shells per gun, main battery: 120
6 - 21.0" / 533.4 mm above water torpedoes

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 23,759 shp / 17,724 Kw = 32.00 kts
Range 1,700nm at 12.00 kts (Bunkerage = 53 tons)

Complement:
63 - 83

Cost:
£0.270 million / $1.079 million

Distribution of weights at normal displacement:
Armament: 10 tons, 1.5 %
Machinery: 347 tons, 53.4 %
Hull, fittings & equipment: 245 tons, 37.6 %
Fuel, ammunition & stores: 48 tons, 7.4 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
166 lbs / 75 Kg = 5.2 x 4.0 " / 102 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.07
Metacentric height 0.6 ft / 0.2 m
Roll period: 12.1 seconds
Steadiness - As gun platform (Average = 50 %): 46 %
- Recoil effect (Restricted arc if above 1.00): 0.44
Seaboat quality (Average = 1.00): 1.20

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.400
Length to Beam Ratio: 10.22 : 1
'Natural speed' for length: 15.17 kts
Power going to wave formation at top speed: 74 %
Trim (Max stability = 0, Max steadiness = 100): 35
Bow angle (Positive = bow angles forward): 5.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 22.00 ft / 6.71 m
- Forecastle (12 %): 22.00 ft / 6.71 m
- Mid (25 %): 22.00 ft / 6.71 m (13.00 ft / 3.96 m aft of break)
- Quarterdeck (10 %): 13.00 ft / 3.96 m
- Stern: 13.00 ft / 3.96 m
- Average freeboard: 15.25 ft / 4.65 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 184.0 %
- Above water (accommodation/working, high = better): 28.1 %
Waterplane Area: 3,186 Square feet or 296 Square metres
Displacement factor (Displacement / loading): 41 %
Structure weight / hull surface area: 23 lbs/sq ft or 112 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.40
- Longitudinal: 10.36
- Overall: 0.55
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is extremely poor

Hi there....

Nice drawing again but this time I think some details need to be corrected.

The TTs seeem too long to be able to turn (diagonal).

The 40mm guns are way too small, methinks. At least WW2-type BOFORs, 2pdr. POM-POMs or German 37mm guns were much larger. The guns shown seem to be of 2cm caliber at best - 12,7mm is even more likely.

Her deck house aft seems distorted.

Why not put her mid-ship gun on her forecastle?

There is a door and scuttles below her funnel but I doubt there is any room for cabins.

Her cross-sectional hull-strength seems too low (<0,5).

You don´t like to draw masts, do you? :o)

Greets,

HoOmAn

I agree about the heavy AA - it really looks like twin 20mm - not just the size but the layout - it appears to be a pedestal mount common to 20mm.
You could probably have a hatch near a funnel - the internal space used by the uptakes is not necessarily the same as the funnel.
As far as having the main battery aft - well many German ww-2 era torpedo boats had similar layout and I guess with the two internal torpedo tubes forward there could be weight issues.

Quoted

There is a door and scuttles below her funnel but I doubt there is any room for cabins.

But who says that that is a real funnel? :-)

I think I can see the deck house underneath the funnel flaring out towards the outside edge of the hull as it moves forward (to allow a good arc fot the torpedo launchers, so there should be some room there to move through a small corridor, its difficult to see with the lifeboats obscuring the deck in the top view. The TT's do seem a bit large while 1.57" do seem a bit small.

I like the design overall, allthough I'm sure the Turks do not.

Thanks for the feedback.

This was updated from the 1921 design and was stronger in SS1 than SS2. I'll look into it.

And I'll look into my 2pdr AA.

Will have to work on masts - just to please Hoo.

The TT are the right size for 21" tubes - I'll check.

These ships are cramped and the forecastle does taper to allow the tubes a better arc.

I think of the first series TB with armour over the CT and a curved protective deck over the machinery as a good fast minesweeper for opposed minesweeping operations in narrow waters. Can Turkey think where I may need these?

These new ships are more like the traditional Med style TB. I think they are too small for the job, probably the reason that this type of ship grew to 800-900tons after navies tried to make a success of 600ton ships. I think I'm only building these to fore fill a 2nd tear level and a need to save DD for other roles, and partly as inertia in my building program.

Cheers,

Quoted

I think of the first series TB with armour over the CT and a curved protective deck over the machinery as a good fast minesweeper for opposed minesweeping operations in narrow waters. Can Turkey think where I may need these?

Turkey can think of where but certainly won't allow them to visit there unannounced or uninvited!

Quoted

unannounced or uninvited

It'll be dark, they'll be painted black. Just listen for 'The Flight of the Valkyries'. ; )

...but only if you or someone else mines the strait first.

Cheers,

Quoted

It'll be dark, they'll be painted black. Just listen for 'The Flight of the Valkyries'. ; )

theres ways around that ;-)

Quoted

...but only if you or someone else mines the strait first.

Well It's doubtfull Turkey would mine the straits unless they themselves felt threatened from another outside force. Atlantis wouldn't be to pleased to run into an unexpected mine from either the Turks or the Greeks on their way to the Byzantine mandate.

Are the Greeks or Atlanteans going to rename the city Constantinople, again?

I can't speak for the Greeks but Atlantis is looking to renew talks about the current Byzantine mandate borders. If Istambul was ever reincorperated into the mandate its likely it would revert to its original name, Constantinople, via peacefull means or course.