Irish Riverboat

[Logi]

Garrison, Irish Riverboat laid down 1913 (Engine 1909)

Displacement:
   200 t light; 219 t standard; 225 t normal; 230 t full load

Dimensions: Length overall / water x beam x draught
   130.00 ft / 129.00 ft x 20.00 ft x 6.00 ft (normal load)
   39.62 m / 39.32 m x 6.10 m  x 1.83 m

Armament:
      2 - 5.00" / 127 mm guns (1x2 guns), 62.50lbs / 28.35kg shells, 1902 Model
     Quick firing guns in deck mount
     on centreline amidships
   Weight of broadside 125 lbs / 57 kg
   Shells per gun, main battery: 200
   4 - 18.0" / 457.2 mm above water torpedoes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   1.00" / 25 mm   107.00 ft / 32.61 m   5.00 ft / 1.52 m
   Ends:   Unarmoured
     Main Belt covers 128 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.50" / 13 mm         -               -

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 2 shafts, 574 ihp / 428 Kw = 14.00 kts
   Range 413nm at 10.00 kts
   Bunker at max displacement = 11 tons (100% coal)

Complement:
   28 - 37

Cost:
   £0.028 million / $0.110 million

Distribution of weights at normal displacement:
   Armament: 16 tons, 6.9 %
   Armour: 24 tons, 10.8 %
      - Belts: 22 tons, 9.8 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 2 tons, 1.1 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 37 tons, 16.3 %
   Hull, fittings & equipment: 84 tons, 37.2 %
   Fuel, ammunition & stores: 25 tons, 11.0 %
   Miscellaneous weights: 40 tons, 17.8 %
                  - 25 tons  FCS
                  - 5 tons  Maraconi
                  - 10 tons  Torpedoes

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     181 lbs / 82 Kg = 2.9 x 5.0 " / 127 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.18
   Metacentric height 0.6 ft / 0.2 m
   Roll period: 10.7 seconds
   Steadiness   - As gun platform (Average = 50 %): 51 %
         - Recoil effect (Restricted arc if above 1.00): 0.43
   Seaboat quality  (Average = 1.00): 1.33

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.509
   Length to Beam Ratio: 6.45 : 1
   'Natural speed' for length: 11.36 kts
   Power going to wave formation at top speed: 56 %
   Trim (Max stability = 0, Max steadiness = 100): 38
   Bow angle (Positive = bow angles forward): -10.00 degrees
   Stern overhang: 1.00 ft / 0.30 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      9.00 ft / 2.74 m
      - Forecastle (20 %):   8.00 ft / 2.44 m
      - Mid (50 %):      6.20 ft / 1.89 m
      - Quarterdeck (15 %):   5.00 ft / 1.52 m
      - Stern:      10.00 ft / 3.05 m
      - Average freeboard:   6.90 ft / 2.10 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 126.9 %
      - Above water (accommodation/working, high = better): 16.0 %
   Waterplane Area: 1,733 Square feet or 161 Square metres
   Displacement factor (Displacement / loading): 81 %
   Structure weight / hull surface area: 30 lbs/sq ft or 148 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.88
      - Longitudinal: 3.03
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is extremely poor
   Good seaboat, rides out heavy weather easily

Unfortunately the designers forgot people are on board

[Guinness]

Unfortunately the designers forgot people are on board

Well, with a range of only 413nm at 10 knots, she's not making very long trips either.

What's the mission here? If it's riverine patrol, the 5" guns and torpedoes are probably overkill. The torpedoes might not work at all in some riverine environments either. If it's coast defense, the range and speed may not be adequate.

[Logi]

It serves as coastal defense as well as riverine patrol

Ireland is pretty small, only 760 nm to do a full trip around it, only 120nm between my two harbors. The range for the ship is 413 nm that's more than enough to travel in ireland's rivers or move from harbor to harbor. It also a little more than half the distance needs to circle Ireland. I think it does quite well given its only 200t on light.

[Guinness]

I'm sorry, I realize my comments might be understood the wrong way. I don't think this is in any way an unsuccessful ship design. I just wanted to understand some of her design rationale.

[Logi]

Its okay, I thought I would take the chance and explain its purpose.

[Korpen]

Considering that you are on an island you fully control, what is the point of investing you very precious build point in ships whose combat capability out at sea is limited to say the least? As the river mouths are under you control anyway it seems bit pointless in investing major ship recourses in protecting the run of the river.

                  - 25 tons  FCS
                  - 5 tons  Maraconi
                  - 10 tons  Torpedoes

If FCS stand for fire control, I think I got bad news: according to your tech report, you are lacking that tech. :(

[Guinness]

In the interest of encouraging peace and prosperity in the N. Atlantic, and encouraging the self defense of a fellow democracy, the CSA proposes building coastal torpedo craft for Ireland.

You can take your pick. Already posted elsewhere is a 250t design, which can be adapted to coal firing, albeit at the expense of range. Here also is a smaller 200t design. One question though is: does this boat's mission require a wireless set? If so, further adaptions might be needed.

The CSA is willing to build these ships for Ireland, or possibly ship engine sets and armament to be installed in Irish built hulls, or a combination of the two.

Irish TB Proposal, Ireland Coastal Torpedo Boat laid down 1913 (Engine 1912)

Displacement:
   200 t light; 208 t standard; 235 t normal; 258 t full load

Dimensions: Length overall / water x beam x draught
   213.00 ft / 205.00 ft x 17.10 ft x 5.53 ft (normal load)
   64.92 m / 62.48 m x 5.21 m  x 1.69 m

Armament:
      2 - 3.50" / 88.9 mm guns in single mounts, 20.00lbs / 9.07kg shells, 1913 Model
     Breech loading guns in deck mounts
     on centreline ends, evenly spread
      2 - 1.00" / 25.4 mm guns (1x2 guns), 0.50lbs / 0.23kg shells, 1913 Model
     Breech loading guns in deck mount
     on centreline aft
   Weight of broadside 41 lbs / 19 kg
   Shells per gun, main battery: 110
   2 - 18.0" / 457.2 mm above water torpedoes

Machinery:
   Coal fired boilers, steam turbines,
   Direct drive, 2 shafts, 6,300 shp / 4,700 Kw = 27.06 kts
   Range 900nm at 15.00 kts
   Bunker at max displacement = 50 tons (100% coal)

Complement:
   29 - 39

Cost:
   £0.031 million / $0.125 million

Distribution of weights at normal displacement:
   Armament: 5 tons, 2.3 %
   Machinery: 121 tons, 51.6 %
   Hull, fittings & equipment: 70 tons, 29.9 %
   Fuel, ammunition & stores: 35 tons, 14.9 %
   Miscellaneous weights: 3 tons, 1.3 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     60 lbs / 27 Kg = 2.8 x 3.5 " / 89 mm shells or 0.1 torpedoes
   Stability (Unstable if below 1.00): 1.23
   Metacentric height 0.5 ft / 0.2 m
   Roll period: 10.0 seconds
   Steadiness   - As gun platform (Average = 50 %): 64 %
         - Recoil effect (Restricted arc if above 1.00): 0.26
   Seaboat quality  (Average = 1.00): 0.82

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.425
   Length to Beam Ratio: 11.99 : 1
   'Natural speed' for length: 14.32 kts
   Power going to wave formation at top speed: 67 %
   Trim (Max stability = 0, Max steadiness = 100): 78
   Bow angle (Positive = bow angles forward): 30.25 degrees
   Stern overhang: 1.00 ft / 0.30 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      12.00 ft / 3.66 m
      - Forecastle (20 %):   9.25 ft / 2.82 m
      - Mid (40 %):      7.00 ft / 2.13 m
      - Quarterdeck (20 %):   5.75 ft / 1.75 m
      - Stern:      5.75 ft / 1.75 m
      - Average freeboard:   7.40 ft / 2.25 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 185.1 %
      - Above water (accommodation/working, high = better): 71.3 %
   Waterplane Area: 2,193 Square feet or 204 Square metres
   Displacement factor (Displacement / loading): 39 %
   Structure weight / hull surface area: 17 lbs/sq ft or 81 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.38
      - Overall: 0.55
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is cramped
   Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

Note: Forward 3.5" mount carries an unarmored spray shield.
Misc Weights: 2 torpedoes, 1 ton reserve
Range at max speed: 160 nm, 5.9 hours

[Logi]

After some considering, I realized the wireless set is not needed as it will doing coastal and river work, well in range of small radio towers.

I do need, however, to adapt it to coal firing as Ireland is lacking in oil supplies.
I take 4-5 of them.

@Korpen
I forgot I didn't have FCS

[Guinness]

Ok, I'll have a look in my 2/1913 report figurings and make sure I can work them in. The good news, is they are so small, they won't be on slips long. ;)

Do you want me with whip up a 250t coal fired proposal, or is the 200 tonner good enough? The advantage of the 200 tonner, of course, is you can have one more for the price if you are ordering 4 or more.

[Logi]

a 200t is good enough

[Guinness]

Okie dokie. I just whipped up 250t, and the advantage is range: 1300nm at 15 knots, 210 at full speed (28 knots in this case).

As I said, I'll double check my building projections, but I expect that 4 or 5 of these little guys in 2/1913 shouldn't be a big problem.

[miketr]

A gunboat of about that size I think wouldn't be a bad idea for Ireland.  Something to sail aroung the coast and patrol Irish waters.  A bit more firepower, a 6" gun and ditch the torpedo's.  At the same time its just a patrol boat with next to no combat value...

Something like this might fit your needs better.

http://www.navalism.org/index.php?topic=2693.0

Its still slow but smaller cruisers just can't ignore it and you could build 1 a year.  At the same time the speed is so low that its tactical use is very limited.  I suspect Ireland wants to look at TB's in the under 1,000 ton range and 1 or 2 PC's as flag ships.

Michael

[Logi]

While that is true, I orginally designed my gunboat with the riverboat rule in mind.
It allows me to build a 200t gunboat for 0.1 BP. Later on I'll start looking for TBs. I'll design my own flagships as I have a specific purpose for them in mind.

[ledeper]

A dual-purpose suggestion as both mine and torpedo craft  


Enter ship name, Enter country Enter ship type laid down 1913

Displacement:
   608 t light; 632 t standard; 709 t normal; 771 t full load

Dimensions: Length overall / water x beam x draught
   231,97 ft / 229,66 ft x 32,81 ft x 6,56 ft (normal load)
   70,71 m / 70,00 m x 10,00 m  x 2,00 m

Armament:
     2 - 4,92" / 125 mm guns in single mounts, 59,59lbs / 27,03kg shells, 1913 Model
     Quick firing guns in deck mounts
     on centreline, all forward, 1 raised mount
     2 - 0,79" / 20,0 mm guns in single mounts, 0,24lbs / 0,11kg shells, 1913 Model
     Breech loading guns in deck mounts
     on side, all amidships
   Weight of broadside 120 lbs / 54 kg
   Shells per gun, main battery: 150
   2 - 18,0" / 457,2 mm above water torpedoes

Armour:
  - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0,39" / 10 mm         -               -

  - Armour deck: 0,39" / 10 mm

Machinery:
   Coal fired boilers, steam turbines,
   Direct drive, 1 shaft, 3.902 shp / 2.911 Kw = 20,00 kts
   Range 3.500nm at 10,00 kts
   Bunker at max displacement = 138 tons (100% coal)

Complement:
   68 - 89

Cost:
   £0,063 million / $0,250 million

Distribution of weights at normal displacement:
   Armament: 15 tons, 2,1 %
   Armour: 37 tons, 5,3 %
      - Belts: 0 tons, 0,0 %
      - Torpedo bulkhead: 0 tons, 0,0 %
      - Armament: 2 tons, 0,3 %
      - Armour Deck: 35 tons, 5,0 %
      - Conning Tower: 0 tons, 0,0 %
   Machinery: 168 tons, 23,7 %
   Hull, fittings & equipment: 303 tons, 42,7 %
   Fuel, ammunition & stores: 101 tons, 14,2 %
   Miscellaneous weights: 85 tons, 12,0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1.089 lbs / 494 Kg = 18,3 x 4,9 " / 125 mm shells or 0,5 torpedoes
   Stability (Unstable if below 1.00): 1,30
   Metacentric height 1,5 ft / 0,5 m
   Roll period: 11,2 seconds
   Steadiness   - As gun platform (Average = 50 %): 54 %
         - Recoil effect (Restricted arc if above 1.00): 0,11
   Seaboat quality  (Average = 1.00): 1,07

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,502
   Length to Beam Ratio: 7,00 : 1
   'Natural speed' for length: 15,15 kts
   Power going to wave formation at top speed: 58 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      13,12 ft / 4,00 m
      - Forecastle (20 %):   10,60 ft / 3,23 m
      - Mid (50 %):      10,60 ft / 3,23 m
      - Quarterdeck (15 %):   10,60 ft / 3,23 m
      - Stern:      10,60 ft / 3,23 m
      - Average freeboard:   10,80 ft / 3,29 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 106,4 %
      - Above water (accommodation/working, high = better): 124,3 %
   Waterplane Area: 4.836 Square feet or 449 Square metres
   Displacement factor (Displacement / loading): 123 %
   Structure weight / hull surface area: 42 lbs/sq ft or 205 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,92
      - Longitudinal: 2,02
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent

Mines 50t
Sweeping gear 15 t
W/L 10
Torpedo Reloads 4t
Reserve 6t

[Logi]

I'll consider the design after i get Ireland up and running.At the moment I lack the BP for larger ships.