WesWorld

A tender for my MTBs She also carries two AC to find targets. She also has a secondary role as a seaplane tender. If this was the 1970s she would make a nice submersible support ship.

Thoughts?

Mexico MTB Tender laid down 1931

Displacement:
1,006 t light; 1,042 t standard; 1,500 t normal; 1,866 t full load

Dimensions: Length overall / water x beam x draught
300.00 ft / 300.00 ft x 35.00 ft x 10.00 ft (normal load)
91.44 m / 91.44 m x 10.67 m x 3.05 m

Armament:
1 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1931 Model
Dual purpose gun in deck mount
on centreline forward
1 - 1.85" / 47.0 mm guns in single mounts, 3.17lbs / 1.44kg shells, 1931 Model
Dual purpose gun in deck mount
on centreline aft
4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1931 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 66 lbs / 30 kg
Shells per gun, main battery: 150
4 - 18.0" / 457.2 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 5,345 shp / 3,987 Kw = 20.00 kts
Range 11,000nm at 15.00 kts
Bunker at max displacement = 824 tons

Complement:
119 - 156

Cost:
£0.282 million / $1.126 million

Distribution of weights at normal displacement:
Armament: 8 tons, 0.5 %
Armour: 3 tons, 0.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 3 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 160 tons, 10.7 %
Hull, fittings & equipment: 485 tons, 32.4 %
Fuel, ammunition & stores: 494 tons, 32.9 %
Miscellaneous weights: 350 tons, 23.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
2,906 lbs / 1,318 Kg = 46.5 x 5.0 " / 127 mm shells or 1.2 torpedoes
Stability (Unstable if below 1.00): 1.31
Metacentric height 1.7 ft / 0.5 m
Roll period: 11.3 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.03
Seaboat quality (Average = 1.00): 1.24

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.500
Length to Beam Ratio: 8.57 : 1
'Natural speed' for length: 17.32 kts
Power going to wave formation at top speed: 49 %
Trim (Max stability = 0, Max steadiness = 100): 40
Bow angle (Positive = bow angles forward): 0.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 15.00 ft / 4.57 m
- Forecastle (15 %): 10.00 ft / 3.05 m
- Mid (40 %): 10.00 ft / 3.05 m
- Quarterdeck (11 %): 7.00 ft / 2.13 m
- Stern: 7.00 ft / 2.13 m
- Average freeboard: 9.24 ft / 2.81 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 65.1 %
- Above water (accommodation/working, high = better): 81.4 %
Waterplane Area: 6,996 Square feet or 650 Square metres
Displacement factor (Displacement / loading): 203 %
Structure weight / hull surface area: 48 lbs/sq ft or 232 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.04
- Longitudinal: 1.13
- Overall: 1.05
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is cramped
Good seaboat, rides out heavy weather easily


Misc weight is used for:
2 AC + spare
crane capable of lifting 35t MTB
hangar for 2 AC or 1 MTB
spare parts
accomodations
extra torpedoes
other

Note: The fuel for the MTBs is covered in by the bunker tonnage.

Comments; shes tiny.

Quoted

Hull has a flush deck
Block coefficient: 0.500
Length to Beam Ratio: 8.57 : 1

Cb of 0.70 and L:B of 6:1 would be more likely.

I've seen a picture of a Cannon class DDE being used as a makeshift tender, so a 1,000 ton vessel can be used to tender MTB's. That being said if this ship is to carry spotter aircraft I'd say she needs to weigh in at around 2,500 tons.

In a pinch, Oil Tankers can be used to transport MTB's in heavier seas. Later on LCT's were converted for the complete servicing of MTB's.

Well she wont carry them just service them. The crane and the long flat quarterdeck make her a sort of mini drydock. But I just noticed that a 70'x20' hangar wont fit, so the hangar will be just for planes. She does carry two AC but no cat. Im trying to keep her small because Mexico just doesnt have alot of money.

Here are a couple of different versions:

Slow version Mexico MTB Tender laid down 1931

Displacement:
1,062 t light; 1,105 t standard; 1,851 t normal; 2,449 t full load

Dimensions: Length overall / water x beam x draught
300.00 ft / 300.00 ft x 40.00 ft x 9.00 ft (normal load)
91.44 m / 91.44 m x 12.19 m x 2.74 m

Armament:
1 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1931 Model
Dual purpose gun in deck mount
on centreline forward
1 - 1.85" / 47.0 mm guns in single mounts, 3.17lbs / 1.44kg shells, 1931 Model
Dual purpose gun in deck mount
on centreline aft
4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1931 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 66 lbs / 30 kg
Shells per gun, main battery: 150
4 - 18.0" / 457.2 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 2,190 shp / 1,634 Kw = 15.00 kts
Range 15,000nm at 15.00 kts
Bunker at max displacement = 1,344 tons

Complement:
140 - 183

Cost:
£0.232 million / $0.930 million

Distribution of weights at normal displacement:
Armament: 8 tons, 0.4 %
Armour: 3 tons, 0.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 3 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 65 tons, 3.5 %
Hull, fittings & equipment: 585 tons, 31.6 %
Fuel, ammunition & stores: 790 tons, 42.6 %
Miscellaneous weights: 400 tons, 21.6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
6,738 lbs / 3,056 Kg = 107.8 x 5.0 " / 127 mm shells or 2.6 torpedoes
Stability (Unstable if below 1.00): 1.40
Metacentric height 2.3 ft / 0.7 m
Roll period: 11.1 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.02
Seaboat quality (Average = 1.00): 1.60

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.600
Length to Beam Ratio: 7.50 : 1
'Natural speed' for length: 17.32 kts
Power going to wave formation at top speed: 38 %
Trim (Max stability = 0, Max steadiness = 100): 44
Bow angle (Positive = bow angles forward): 0.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 15.00 ft / 4.57 m
- Forecastle (15 %): 12.00 ft / 3.66 m
- Mid (40 %): 12.00 ft / 3.66 m (10.00 ft / 3.05 m aft of break)
- Quarterdeck (11 %): 10.00 ft / 3.05 m
- Stern: 10.00 ft / 3.05 m
- Average freeboard: 10.98 ft / 3.35 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 39.8 %
- Above water (accommodation/working, high = better): 106.0 %
Waterplane Area: 8,777 Square feet or 815 Square metres
Displacement factor (Displacement / loading): 309 %
Structure weight / hull surface area: 48 lbs/sq ft or 236 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.00
- Longitudinal: 1.19
- Overall: 1.02
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather


********************************************


Fast version, Mexico MTB Tender laid down 1931

Displacement:
1,185 t light; 1,228 t standard; 1,851 t normal; 2,351 t full load

Dimensions: Length overall / water x beam x draught
300.00 ft / 300.00 ft x 40.00 ft x 9.00 ft (normal load)
91.44 m / 91.44 m x 12.19 m x 2.74 m

Armament:
1 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1931 Model
Dual purpose gun in deck mount
on centreline forward
1 - 1.85" / 47.0 mm guns in single mounts, 3.17lbs / 1.44kg shells, 1931 Model
Dual purpose gun in deck mount
on centreline aft
4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1931 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 66 lbs / 30 kg
Shells per gun, main battery: 150
4 - 18.0" / 457.2 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 6,561 shp / 4,894 Kw = 20.00 kts
Range 12,500nm at 15.00 kts
Bunker at max displacement = 1,123 tons

Complement:
140 - 183

Cost:
£0.331 million / $1.324 million

Distribution of weights at normal displacement:
Armament: 8 tons, 0.4 %
Armour: 3 tons, 0.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 3 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 196 tons, 10.6 %
Hull, fittings & equipment: 628 tons, 33.9 %
Fuel, ammunition & stores: 667 tons, 36.0 %
Miscellaneous weights: 350 tons, 18.9 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
4,894 lbs / 2,220 Kg = 78.3 x 5.0 " / 127 mm shells or 1.6 torpedoes
Stability (Unstable if below 1.00): 1.43
Metacentric height 2.4 ft / 0.7 m
Roll period: 10.9 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.02
Seaboat quality (Average = 1.00): 1.23

Hull form characteristics:
Hull has low quarterdeck
Block coefficient: 0.600
Length to Beam Ratio: 7.50 : 1
'Natural speed' for length: 17.32 kts
Power going to wave formation at top speed: 53 %
Trim (Max stability = 0, Max steadiness = 100): 40
Bow angle (Positive = bow angles forward): 0.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 17.00 ft / 5.18 m
- Forecastle (15 %): 12.00 ft / 3.66 m
- Mid (40 %): 12.00 ft / 3.66 m
- Quarterdeck (25 %): 10.00 ft / 3.05 m (12.00 ft / 3.66 m before break)
- Stern: 10.00 ft / 3.05 m
- Average freeboard: 11.80 ft / 3.60 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 59.4 %
- Above water (accommodation/working, high = better): 119.1 %
Waterplane Area: 8,777 Square feet or 815 Square metres
Displacement factor (Displacement / loading): 228 %
Structure weight / hull surface area: 51 lbs/sq ft or 248 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.00
- Longitudinal: 1.38
- Overall: 1.03
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is adequate
Good seaboat, rides out heavy weather easily


NOTE: The quarterdeck is 75 feet long and can hold a 70ft MTB.

Mexico could always convert an elderly ship to fill the role of MTB tender on the cheap.

Would it be possible to build this ship in such a way that the quarterdeck could be turned into a drydock?

Like HMS Albion?

In case Gavin's pretty picture didn't answer your question, it is possible - there's a historical Brazilian sub tender with something similar, and I think Atlantis has built something like it too.

I don't think you could build it into a refit, though, if that's what you're asking.

Yup like Albion. The question is, could you do it in a ship (newbuilt) of only 1,000 tons? The ships which would use the drydock are MTBs:
Dimensions: 70x19x5
displacement: 35 tons

Technically, maybe. But on a ship of 1000 t, that'd be a significant portion of the ship's internal space, and that much water might be an issue for buoyancy, stability, and what not. Might not be practical.

An alternative to consider is just to sling the MTB onto the deck with a derrick. Much simpler...

I'd go significantly bigger than 1,000 tons. The Atlantean sub tender is designed to service coastal subs (450 tons)in its hold. I'd say 4,000 tons is more practical for an MTB tender that performs a similar range of tasks for MTB's rather than subs.

A berthing area of 230x45 should be more than enough space for 6 MTB's of the current type operated by Mexico or most future designs. Crew accomidations for roughly 50 people and some sort of repair shop would also be usefull. Atlantis needs a new class of MTB tenders, perhaps co-operation with Mexico could result in a modification to the Patronus class design to service MTB's?

Patronus class, Multi purpose sub ship (MPSS ship)



Patronus(protector), Efficax (effective)
Atlantian Sub repair,depot,docking and salvage ship laid down 1924

Displacement:
6,761 t light; 6,914 t standard; 7,131 t normal; 7,277 t full load
Loading submergence 422 tons/feet

Dimensions:
325.00 ft x 64.00 ft x 20.00 ft (normal load)
99.06 m x 19.51 m x 6.10 m

Armament:
2 - 4.00" / 102 mm guns
4 - 3.00" / 76 mm guns
6 - 1.00" / 25 mm guns
Weight of broadside 121 lbs / 55 kg

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 3,750 shp / 2,798 Kw = 14.00 kts
Range 5,000nm at 10.00 kts

Complement:
388 - 504

Cost:
£0.824 million / $3.297 million

Distribution of weights at normal displacement:
Armament: 15 tons, 0.2 %
Machinery: 124 tons, 1.7 %
Hull, fittings & equipment: 3,623 tons, 50.8 %
Fuel, ammunition & stores: 370 tons, 5.2 %
Miscellaneous weights: 3,000 tons, 42.1 %

Metacentric height 2.7

Remarks:
Hull space for machinery, storage & compartmentation is excellent
Room for accommodation & workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable and able to fight her guns in the heaviest weather

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.02
Shellfire needed to sink: 12,214 lbs / 5,540 Kg = 381.7 x 4.0 " / 102 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 2.8
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 70 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.01
Relative quality as seaboat: 1.88

Hull form characteristics:
Block coefficient: 0.600
Sharpness coefficient: 0.45
Hull speed coefficient 'M': 5.16
'Natural speed' for length: 18.03 kts
Power going to wave formation at top speed: 40 %
Trim: 37
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 54.0 %
Relative accommodation and working space: 101.5 %
(Average = 100%)
Displacement factor: 212 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 2.15
(Structure weight / hull surface area: 171 lbs / square foot or 836 Kg / square metre)
Relative longitudinal hull strength: 4.72
(for 14.00 ft / 4.27 m average freeboard, freeboard adjustment -0.15 ft)
Relative composite hull strength: 2.33

http://www.hazegray.org/mysteries/oldmyst/ans160.htm

Submarine tender Ceara with 216' docking well and crane capable of lifting 400tons. Can someone with Jane's or Conway's to hand post some dimensions and tonnage?

Albion is different. She trims down by the stern and the water level comes up into the "hangar". Normally its high and dry.

1000tons is far too small for this. Taking Albion as a benchmark and deleting stores for marines and you're looking at a newbuilt 10000t ship.

I was thinking a smaller version of the Indian Tender.
http://wesworld.jk-clan.de/thread.php?th…478aafc5&page=2

I guess the drydock wont work. Are there any cranes capable of lifting 35 tons?

I would love to have a bigger ship, but Mexico doesnt really have a lot of cash. Also smaller ships can go where bigger vesselas cant.

Crane Ship No. 1 can lift 250tons.

Nothing that drastic!!! Its gotta fit in a 1,000 ton ship after all.

I guess Im going to have to scrap the idea of actually repairing MTBs on board. Its to complicated and impractical in 1,000 tons.

Quoted

Originally posted by Red Admiral
http://www.hazegray.org/mysteries/oldmyst/ans160.htm

Submarine tender Ceara with 216' docking well and crane capable of lifting 400tons. Can someone with Jane's or Conway's to hand post some dimensions and tonnage?

Here you go Gavin.

Length PP 328 feet, beam 52 feet

Draught and displacement varies

a)with dock empty and gate closed: 4,100 tons, 14' draft
b)with dock gate open and dock flooded: 4,130 tons, 17', 5" draft
c)with gate closed and submarine docked: 4560 tons 15' draft
d)with gate closed and submarine under hydrolic pressure test in dock: 6460 tons 20',5" draft
e)a)with dock empty and gate closed when raising submarine by double cranes at stern: 4,615 tons, 15' draft

Sufficient fuel carried to fill tanks of six subs four times
equipment caried includes 2 150kw charging dynamos, two electric and one steam-driven 75-150 atmos.air compressors, refrigerating plant, workshops and pumps to empty dock in 2 hours.
Carries spare battery's torpedos stores ect. for 6 subs

Quoted

Originally posted by Desertfox
Nothing that drastic!!! Its gotta fit in a 1,000 ton ship after all.

I guess Im going to have to scrap the idea of actually repairing MTBs on board. Its to complicated and impractical in 1,000 tons.

Not nessasarilly Foxy, you can take a merchie and convert it to hold two extra large overhanging gantry's as per the Japanese Hakusa. She weighed in at 6,800 tons and could launch fast patrol boats while underway.

I'm contemplating a conversion similar to this for my own MTB's which are the same type used by Mexico.
This type of convertion would be a cheap way of using 1,000 tons of materials on a much larger ships tonnage.