Mine sweeper

[Carthaginian]

Cork and industrially-refined cellulose are a lot less dense than wood.
Wood gets waterlogged enough to sink, less dense cork bark and refined cellulose don't. I was just wondering if there might be something better that could be used, like your two suggestions, rather than the wood blocks it sounded like he was intending to use.

It rather depends on what kind of wood, and for how long it will be drenched.
And even waterlogged it weigh a lot less the just water. In effect it prevents the mine breaker from sinking at the first mine. :)
Add to that, wood has the rather nice advantage of being ceap and easy to get everywere, so it is what will be used if notinh better is around.

OK, as most everyone can tell, I'm not exactly the most experienced 'designer' around... and thus I'm not always sure as to the whys and hows of things. All I could think of is how most waterlogged wood I know of manages to float... about half-an-inch below being 'sunk'. :)

[Borys]

Ahoj!
Don't leddem talk ya down! Wet wood floats. Period.
But minesweepers are better in clearing minefields than merchants carrying wood ....

Borys

[Korpen]

Ahoj!
Don't leddem talk ya down! Wet wood floats. Period.
But minesweepers are better in clearing minefields than merchants carrying wood ....

Borys

The purpose of that technique is not to clear a mine field, it is to cross it,  so if you have a flotilla of ships that are to leave port (or attack an enemy) and you suspect that in rout might be mined, you add a mine breaker to the head of the line, and let all ships sail in the wake of the breaker. Not the safest way, but it is fast.

[swamphen]

Realised I never posted* the DKB version of the design...

The 'CT armour' is some cheap** armour plate around the bridge to deflect bullets, splinters, stray seagulls, etc.

MSB-1, German Minesuchboot laid down 1907 (Engine 1909)

Displacement:
   358 t light; 369 t standard; 417 t normal; 456 t full load

Dimensions: Length overall / water x beam x draught
   164.86 ft / 164.86 ft x 19.03 ft x 7.02 ft (normal load)
   50.25 m / 50.25 m x 5.80 m  x 2.14 m

Armament:
      1 - 3.46" / 88.0 mm guns in single mounts, 22.05lbs / 10.00kg shells, 1900 Model
     Breech loading gun in deck mount
     on centreline forward
      2 - 0.30" / 7.7 mm guns in single mounts, 0.01lbs / 0.01kg shells, 1907 Model
     Breech loading guns in deck mounts
     on side, all amidships

   Weight of broadside 22 lbs / 10 kg
   Shells per gun, main battery: 150

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:      0.79" / 20 mm         -               -

   - Conning tower: 0.79" / 20 mm

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 1 shaft, 2,200 ihp / 1,642 Kw = 18.05 kts
   Range 2,600nm at 10.00 kts (Bunkerage = 87 tons)

Complement:
   46 - 60

Cost:
   £0.038 million / $0.154 million

Distribution of weights at normal displacement:
   Armament: 3 tons, 0.6 %
   Armour: 2 tons, 0.6 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 1 tons, 0.3 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 1 tons, 0.2 %
   Machinery: 169 tons, 40.6 %
   Hull, fittings & equipment: 134 tons, 32.2 %
   Fuel, ammunition & stores: 59 tons, 14.1 %
   Miscellaneous weights: 50 tons, 12.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     255 lbs / 116 Kg = 12.3 x 3.5 " / 88 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.17
   Metacentric height 0.6 ft / 0.2 m
   Roll period: 10.7 seconds
   Steadiness   - As gun platform (Average = 50 %): 72 %
         - Recoil effect (Restricted arc if above 1.00): 0.12
   Seaboat quality  (Average = 1.00): 1.53

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.663
   Length to Beam Ratio: 8.66 : 1
   'Natural speed' for length: 12.84 kts
   Power going to wave formation at top speed: 64 %
   Trim (Max stability = 0, Max steadiness = 100): 47
   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:         14.44 ft / 4.40 m
      - Forecastle (20 %):      9.19 ft / 2.80 m
      - Mid (50 %):      9.19 ft / 2.80 m
      - Quarterdeck (15 %):   9.19 ft / 2.80 m
      - Stern:         9.19 ft / 2.80 m
      - Average freeboard:      9.61 ft / 2.93 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 149.1 %
      - Above water (accommodation/working, high = better): 91.4 %
   Waterplane Area: 2,403 Square feet or 223 Square metres
   Displacement factor (Displacement / loading): 101 %
   Structure weight / hull surface area: 27 lbs/sq ft or 131 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.84
      - Longitudinal: 4.63
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is cramped
   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

* - Or created, for that matter...

* - ACME Triple Strength Battleship Armour Plate, to be exact.