Wet Ships

Most colony worlds will have substantial oceans as well as lakes and rivers. These bodies of water can become means of transportation between a colony town and its farms, or among several colony sites. Water may also be an avenue of exploration beyond the settled area. All you need to take advantage of water transportation are wet ships. Here are design sequences that enable the Traveller New Era referee to design muscle, wind, and steam-powered vessels that can be built using the resources of a colony world. Note that part of this design sequence uses some system and subsystem design sequences published in GDWs publication Fire, Fusion, and Steel. You should have a copy of Fire, Fusion, and Steel available as you will need some of the tables and other information contained in that publication. For convenience, Fire, Fusion, and Steel is often refered to as 'FF&S' in this chapter.

The Law of Buoyancy

All vessels that float on the oceans of a world observe a basic natural law that affect every aspect of their design, be they hollow logs or fusion powered submersibles. This basic law is the law of buoyancy. Buoyancy works like this: if an object weighs less than the weight of fluid it displaces, it will float in the fluid. If it weighs more than the displaced fluid, the object will sink. This law applies to any fluid be it a gas or a liquid. Buoyancy enables steel ships to float on oceans and balloons filled with light gases to float in atmospheres.

Wet Vessels

With buoyancy as a starting point, virtually any wet vessel may be designed using these basic design sequences. These include:

Non-Powered Vessels: These include muscle and wind-driven craft ranging from simple rafts propelled by polling or rowing to large sail-powered merchant vessels and warships.

Powered Vessels: These include surface craft beginning with TL 4 steam-powered paddle driven riverboats and steam/sail vessels.

Ship Design Factors

Units Used in Ship Design

Displacement Tons-- This is the standard Traveller hull volume measurement. One displacement ton is equal to 14 cubic meters of volume (the volume occupied by one ton of hydrogen). In Wet Navy ship design, the hull's resistance through the water and the vessel's resulting power requirement to reach a desired speed is calculated using displacement tons. This unit is also used to calculate the speed that can be reached with a given amount of power.

Metric Tonnes-- One metric tonne of displacement is equal to 1 cubic meter of volume (the volume occupied by one ton of water). It is also equal to one ton of mass. The vessel's weight, the weight of the water it displaces, and the available free buoyancy is calculated in metric tonnes.

Cubic Meter-- The cubic meter is the standard unit of volume. One cubic meter equals one kiloliter in volume. One cubic meter of water weighs one metric tonne. 14 cubic meters of hydrogen weighs one metric tonne, and equals one Displacement Ton in volume.

Kilowatts-- One kilowatt equals 1,000 watts. This is the standard unit of power for small water craft.

Megawatts-- One megawatt equals 1,000 kilowatts. This is the standard unit of power for large water craft.

Kilometers per hour-- This is the standard unit of speed in Traveller. Two kilometers per hour are roughly equal to the ancient Terran "knot" unit of speed.

Step 1: Design Hull

Displacement is the weight of the fluid moved aside by a vessel's hull when it is floating or submerged in the fluid. If the displacement of the vessel is greater than the weight of the vessel, the vessel floats. If the displacement is less than the weight of the vessel, the vessel sinks.

Displacement is the starting point for all ship or boat designs. It is a fraction of the total hull volume expressed in displacement tons converted to the weight of the fluid it displaces (usually water) expressed in metric tonnes. The percentage of total hull volume varies with hull type. A submerged submarine, as an example, displaces 100 percent of its hull volume. On the other hand, a planing hull displaces only 30 percent of its total volume.

Displacement is calculated at one standard gravity as is the weight of the craft being designed. If the vessel is built on a world with a greater or lesser gravity, the gravity affects the weight of the fluid and the weight of the vessel equally. Therefore, the ratio of displacement to weight is independent of local gravity. However, the absolute weights of the displaced fluid and the vessel are not. A vessel that weighs more than the fluid it displaces on a .7 G world will sink just as surely as one on a 1.2 G planet. Displacement is listed in tonnes for vessels of one tonne or greater, in kilograms for smaller vessels.
To calculate the displacement vs. the weight of standard hulls listed on the Hull Size table in Fire, Fusion, and Steel:

1. Select a hull size from the Rate column in the FF&S Hull Size Table, and the material from which it is to be built from the Wet Ships Hull Materials Table.

2. Decide upon the thickness of the hull in centimeters. A thicker hull will have a greater armor value but it will weigh more. The minimum permitted thickness, regardless of the hull material selected, should be 0.40 centimeters.

3. Calculate the volume of the hull material using the procedure found in the 'Hulls'section of Chapter 1 of Fire, Fusion, and Steel. Then, multiply this figure with the appropriate weight modifier from the Hull Materials Table. Finally, multiply this number by the hull's actual thickness in centimeters. The resulting numbers is the hull's true weight in metric tons. The equation appears below:

    (Basic Hull Weight) x (Wgt Modifier) x (thickness in cm) = True Wgt 

Hull Materials Table

TL  Hull Material        Toughness      Tonnes per     Price (MCr)
                         Modifier       Cubic Meter

0   Cured Hides (Z)      .02            0.1             -
0   Bone/Lgt. Wood (Y)   .1             0.4             -
1   Wood (W)             .2             0.7             0.0005
4   Iron (I)             1.5            8               0.0016
5   Soft Steel (A)       1.7            8               0.0016
6   Hard Steel (B)       2              8               0.002
7   Compos. Lam. (C)     6              8               0.008
7   Aluminum  (Ca)       1              3               0.0015
7   Fiberglass (Cf)      .25            1               0.001
8   Titanium Alloy (Ct)  3              8               0.010


4. Determine the hull's armor value. To do this, multiply the hull material's Toughness Modifier by the hull's thickness in centimeters. The resulting number is the hull's equivalent Armor Value.

5. Note the hull's volume in cubic meters from the Fire, Fusion & Steel Hull Size table.

6. Determine the hull type.

7. Multiply the hull's displacement tonnage by the "% of Hull Displacing Fluid" figure for the selected hull type. This yields the volume in displacement tonnage of the portion of the hull that displaces fluid and the volume in displacement tonnage of fluid displaced.

Figure 1.

The volume of the fluid displaced is a percentage of the hull's displacement. This diagram shows a curved displacement hull vessel that displaces 50% of its hull displacement. The superstructure is separate from the hull and either of its displacements. The superstructure's volume and weight are calculated separately from the hull and added to those of the hull. Superstructures are discussed later in this chapter.

Hull Type Table

Hull Type            Resistance     % of Hull     Price
                                    Displacing    Modifier
                                    Fluid

Deep Displacement         0.9       90%           0.75
Parallel Displacement     0.7       75%           0.85
Curved Displacement       0.5       50%           1.00
-----
*For basic hull only.  Thrust based-transmission must be added.

8. Multiply the tonnage of the displaced fluid by 14, then multiply the result by the appropriate modifier from the Fluid Density Table. This yields the weight of the fluid the vessel displaces. If the displaced fluid's weight is greater than the vessel's weight, the vessel floats; if less, the vessel sinks.

Fluid Density Table

Fluid Density Multiplier

Fresh Water 1.0 Sea Water 1.0 Ammonia 0.75 Methane 0.7

The result is the weight of the fluid displaced by the hull.

9. Compare the weight of the hull with the weight of the displaced fluid. If the fluid weighs more, the vessel will float, if the vessel weighs more, it will sink. In that case, build a larger hull or choose a lighter hull material.

Length, Beam and Depth

Wet ship hulls are equivalent to a needle shaped spacecraft hull in terms of determining length from the FF&S Hull Size table. The maximum beam (width) of a hull is the length divided by 3. Finally, determine the depth of the hull (from the keel at the bottom of the hull to the main deck at the top) The result of multiplying these three figures together should equal the hull volume in cubic meters. As an example, a 1000 displacement ton hull with a volume of 14,000 cubic meters will be 90 meters long, 30 meters wide, and 15.5 meters deep.

Free Buoyancy

Free Buoyancy is the figure expressed in tons or kilograms calculated by subtracting the total weight of a vessel from the weight of the fluid it displaces. This is the weight of all additional elements you may add to the design until the vessel sinks. Calculate free buoyancy at each step during the design process when the weight of new elements such as weapons, cargo space, superstructure, fuel tankage, and crew accommodations are added to the design.

Weight

Weight is the total weight of the vessel listed in tons for large craft and kilograms for small craft of less than one ton. This figure includes the weight of the hull, superstructure if any, propulsion machinery, fuel, cargo, weapons, crew, passengers, and in the case of wind-driven craft, sails and masts. Hull weight varies widely and depends on the size of the vessel and the weight per ton of displacement of the material from which the hull is made.

Hull Form

After you have determined your displacement and the weight of the hull, select the hull form from the hull table. This determines the resistance of the vessel through the water, and each hull form's resistance figure affects the power needed to reach a powered vessel's design speed. These hull forms include:

Deep Displacement-- These are high capacity hulls are suitable for large merchant ships such as tankers and bulk carriers. However, they require more power to reach and sustain a given speed than other displacement hull types. Some 80 to 90 percent of a fully loaded deep displacement vessel's hull is below the water line.

Parallel Displacement-- Both sides of a parallel displacement hull run parallel to each other except at the bow and stern. Although easier and cheaper to build, this hull form has higher drag than a curved displacement hull. Most medium-sized merchant ships including freighters and passenger liners have parallel displacement hulls.

Curved Displacement-- This is the hull form used for most surface warships. The hull begins with a sharp bow and gently curves around the widest part of the hull, then tapers into the stern. The displaced fluid flows more efficiently with less drag around a curved hull. A vessel with a curved displacement hull will travel at a higher speed than a parallel displacement hull using the same amount of power.

Step 2A: Power

Power is needed to drive the vessel through the water. This can come from several sources including muscular power (from humans, other sentients or animals), wind power, or mechanical power.

The Types Available

Power interacts with the vessel's displacement and its hull form to produce velocity through the water. Mechanical power can be constant and drive a vessel at a constant maximum speed. Wind power is variable and is applied through a different set of principles than mechanical power, and requires its own design sequence. Muscle power may be constant for a period of time then decline.

After determining the hull's displacement, its material, configuration, and weight, the ship designer must choose the vessel's source of power. If the designer chooses to design an wind-powered vessel, he or she would skip to the wind-powered design sequence found later in this chapter. Otherwise, the designer should continue with the powered ship design sequence beginning in the next paragraph.

Powered Ships

A powered ship may range from a paddle-powered canoe to a steam boat. The design sequence is basically the same for each of these vessels and any other vessel that has a relatively constant source of power. To design a powered vessel:

Determine top design speed-- This is the maximum speed at which your vessel can travel. Note that power requirements increase by a factor of eight for each doubling of the top design speed.

Calculate hull resistance-- Use the formula R=(WD) x rf where WD is the square root of the hull's displacement multiplied by the percentage of the hull actually in the water and rf is the hull resistance factor found with each hull type in the Hull Types table. The result is R: hull resistance.

Calculate power needed to reach design speed with fully loaded hull-- Do this with the formula P=(RV2/2)where P is power in kilowatts, R is the hull's resistance calculated in the previous step, and V is the top design speed. If you wish to calculate the power in megawatts divide the result by 1000 or calculate the power needed with the formula P=RV2/2000.P=(RV2/2000)x(WD)

Determine power plant-- Power plants that can be easily built on a colony world range from primitive steam engines available at TL 3 through TL 5 steam turbines. Power plants available at TL's 3 through 5 are listed in the power plant table included with this article. These include steam reciprocating, steam turbine, and internal combustion. As with other vehicle designs, install as many cubic of power plant as you need to produce the output needed to reach the top design speed as well as to provide for the vessel's other power needs. Note the weight of the power plant and subtract it from the available free buoyancy. Also, note the total fuel consumption of the power plant.

                     Power Plant Table
       (unless stated otherwise, values are per cubic meter)

TL  Type           PowOP   Price   Wgt.  Min.   Fuel   Fuel Type
                   MW/KL                 Vol.   KL/Hr

3  Early Steam
    Reciprocating 0.10     0.0005  2    0.25   0.15    Hydcrb (S)
5  Steam Reciproc 0.20     0.0005  2    0.15   0.15    Hydrocrb
5  Steam Turbine  0.35     0.002   2    1      0.15    Hydrocrb
4  Internal Comb. 0.30     0.001   1    0.05   0.2     Hydrocrb

* Hydrocarbon (S) indicates that this engine can only be built to
accept Wood or Coal.

Fuel Options: Steam engines of all types can be designed to use Wood or coal instead of Hydrocarbon distillates. Steam engines of TL 3 and 4 can ONLY use Wood or Coal.
If wood is used, multiply energy output by 0.5 and fuel consumption by 3.
If coal is used, energy output remains the same but fuel consumption is multiplied by 1.5.

----

Cold-Starting and Accelerating with Steam Engines All steam engines require 5 minutes to be cold-started. For every 50 kilowatts of power output (or fraction thereof), they require one additional minute. Therefore, a steam engine with a maximum output of 100 kilowatts would require 7 minutes to start.

In the event that a steam engine is not being run at maximum output, it requires 1 minute to generate every additional 50 kilowatts of power that it wishes to add. Therefore, if a 200 kilowatt steam engine was running at only 50 kilowatts output, it would take three minutes (of full fuel consumption) to increase its output level all the way to the maximum of 200 kilowatts.

Step 3A: Power Transmission


Determine Power Transmission-- Choose one from the Marine Power Transmission Table. These may be paddle wheels, screw propellers, hydrojets, or gravitic drive units. Note the efficiency multiplier of each unit. Multiply the power needed to reach the design speed with this multiplier and adjust the power or speed as needed. Note the weight and volume of each transmission unit and subtract the weight from the available free buoyancy. Where applicable, subtract the volume from the available hull volume.

Marine Power Transmission Table

	TL	Type		Efficiency	Diameter Ratio		Weight		Volume		Cost

	3	Side Wheel	.75		1/10			1 ton/meter	1KL/meter	100/meter
	4	Stern Wheel	.80		1/10			3 ton/meter	3KL/meter	300/meter
	4	Screw		.95		1/1000			7 ton/meter	1KL/meter	1000/meter
            ------
Diameter Ratio = meters in diameter of wheel, screw, or jet per metric tons of
	vessel  being propelled.  Note that where propeller diameter becomes
	excessive, the total diameter may be divided among two or more
	propellers.  Propeller diameters may not exceed 10 meters.
Weight = ton per meter in diameter of wheel, screw, jet, or tunnel.
Volume = KL/meter in diameter of wheel or screw.
KL/ton = internal hull volume used for power transmission.
Cost = Credits per meter in diameter of wheel, screw, jet, or tunnel.

Available power transmission types, their advantages and disadvantages include:

Side Paddle Wheel-- This is the least efficient and most primitive marine power transmission. These have been used aboard inland and deep sea vessels, mostly powered by primitive steam engines. Side wheels are best suited for calm waters, and may be better suited to extremely shallow waters than screw propellers. Also, they greatly aid steering a vessel in tight quarters. An experienced ship's captain can spin a vessel around its vertical axis by going forward with one side wheel and reversing the other.

Side wheels are susceptible to damage. A collision, debris in the water, or a well placed shot could destroy a side wheel. They also cause problems in docking. And, in rough seas, they may be intermittently thrown clear of the water and race, causing damage to the engine by the rapidly varying load.

Stern Paddle Wheel-- As the name suggests, stern wheels are located at the stern of the vessel. Because they are located in the vessel's wake, they are more efficient than side wheels. They are also less susceptible to damage.

Stern wheels are best suited to calm inland waters and may experience racing and cause engine damage in rough ocean waters. They can also become quite large and bulky, and would not be suited for propelling large vessels.

Screw Propellers-- Screw propellers are the most common transmission devices and are the most efficient marine power transmissions for speeds up to 65 kph at mid-technology levels. They share the advantage of paddle wheels of not occupying volume within the vessel's hull. And they are relatively small and light compared with other transmissions for the size of vessels they propel.

Step 2B: Sail Power

Wind pressure against the sails as well as aerodynamic forces, particularly with fore and aft rigged sailing vessels, generate the power that drive a vessel forward. Because wind is variable, the force that powers the vessel is variable. However, since it is possible to determine the maximum number (and area) of sails a ship can carry without being driven under, and its possible to determine the force generated by the wind blowing against these sails, the maximum speed for a sailing vessel can be pre-determined.

Sail Configurations-- There are two basic sail configurations:

1. Square rigged

2. Fore and aft

These configurations may be and often are combined on sailing vessels with more than one mast.

Square rigged-- Square rigged sails are large rectangles of cloth rigged perpendicular to the hull's main axis. They are designed to catch winds coming from the stern and from within 45 degrees from either side of the stern and take maximum advantage of these winds. To enable the vessel to sail courses closer into the wind and to help in tacking, a square rigged water craft often has a number of fore and aft sails mounted both on its after most mast and as jibs close to the bow. Square riggers are well suited for worlds with steady winds blowing from predictable directions where trade routes can take advantage of wind directions. Large merchant and men of war sailing vessels are square rigged.

Fore and Aft rigged-- These sailing craft have their sails mounted parallel to the main axis of the ship. They are exceptionally well suited for sailing with the wind coming from the beam and for sailing high up into the wind, where aerodynamic forces can pull the vessel along rather than push it. Fore and aft rigged craft are much less efficient than square riggers in taking advantage of a following wind because the after-most sail often blocks the wind from driving other sails to forward. Choose this type of rig if your craft is sailing in confined waters where frequent tacking and turning take place, or where you can't count on a steady wind from the same direction.

Sail Area-- The total sail area determines the maximum amount of force available to power a sailing vessel, and consequently the vessel's top speed. This area depends on the height and number of the vessel's masts, and the length of the yards-- wooden or metal beams that run at right angles to the mast.

Masts may be added at a rate of one per 15 meters of the ship's length. Large sailing ships are known to have three to five masts, while seven or eight masts are not unknown on the largest ships. Maximum mast height in meters equals the square root of a hull's volume in cubic meters. Maximum mast height for any vessel is fifty meters. Yards on square-rigged ships may be 130% the length of the beam. Yards on fore and aft-rigged vessels equal 50% the mast height in length.

With a square rig, calculate the sail area based on the rectangular area of the total number of sails rigged on the masts, plus 20 percent of the total to allow for jibs and stay sails rigged at the bow or between the masts. Fore and aft rigged vessels have basically triangular sails; one per mast, plus an additional 10 percent for jibs rigged at the bow.

Sail Power-- The power generated by wind on sails is determined in a standard atmosphere by this procedure:
1. Multiply the wind velocity in kilometers per hour by 0.28 to convert the wind velocity to meters per second.
2. Calculate the power available in watts with this formula. P = {[(1286)S]V} 0.1
Where P = power in watts
Where S = sail area
Where V = wind velocity in meters per second

On a world with a dense atmosphere, multiply the resulting force in watts by 1.5.; on a world with a thin atmosphere multiply by .75. Sails are impractical on worlds with very thin or trace atmospheres. Note: One kiloliter of standard atmosphere air weighs 1286 kilograms. This determines the constant in the formula used above.

Here are two examples of how ten kilometers per hour of wind can produce a vastly different amount power, depending on the sail area. The power output in both cases would increase as the wind velocity increases.

sail area wind in km/hr wind in m/s watts kilowatts 200 10 2.8 72016 72.016 1 10 2.8 360.08 0.36008

Note: When the power output (in kilowatts) of wind on the vessel's sails exceeds its hull volume (in cubic meters), the vessel's sails begin to take damage equal to 1 point per kilowatt of excess power. If the power output exceeds its hull volume (in cubic meters) plus its free Buoyancy, the vessel is either capsized (if it has a beam wind) or is driven under (if it has a following wind). If the vessel has wooden masts rather than iron or steel, the masts break when the wind load exceeds 75 percent of the vessel's displacement.

Sails should be shortened to reduce their area in heavy weather to prevent these disasters, and the ship should be headed into the wind in extreme cases.

When the total sail area is determined, calculate the potential speed expected at several wind velocities. Do this by calculating the power generated by the wind at various wind speeds, then calculate the potential speed with the formula: V2=P2/R where P is force in kilowatts and R is hull resistance.

This formula is based on kilowatts of power modified by the resistance of vessel's hull. Use the formula R=(WD) x rf where WD is the square root of the hull's displacement multiplied by the percentage of the hull actually in the water and rf is the hull resistance factor found with each hull type in the Hull Types table. The result is R: hull resistance.
Note that in some cases this calculation may result in vessel speeds exceeding wind speeds. If this occurs, reduce vessel speed to wind speed.
Sail Damage-- Determine sail damage levels: Divide the total sail area by 15 to calculate the level to destroy half the sail area; divide by 6 to calculate the level to destroy the sails and demast the vessel. Double these damage values for extra-strength synthetic sails.

Sail Costs-- Sails cost CR100 per square meter.

Sail Weight-- Dry canvas sails weigh approximately 1 kilogram per square meter. When wet, increase their weight to 2 kilograms per square meter. Synthetic sails (TL7) weigh 0.9 kilograms per square meter. However, they do not soak up water and weigh approximately the same wet or dry. Extra-strength synthetics (TL8) weigh 0.3 kilograms per square meter wet or dry. Sail Stowage Volume-- Canvas sails require 1 cubic meter of volume for every 25 square meters of sail area when stowed below decks (they may alternatively be furled on their yard arms.) Synthetic sails require .5 cubic meter of volume per 25 square meters, and extra-strength synthetics .3 cubic meter per 25 square meters.

Mast Weight and Cost-- Wooden masts weight 10 kilograms and cost CR 10 per meter of height. Iron masts become available at TL 4: they weigh .125 tons and cost CR 100 per meter of height.
Steel masts become available at TL 5: they weigh .1 ton and cost CR 100 per meter. Titanium masts become available at TL 7: they weigh 60 kilograms and cost CR 200 per meter. These values include the weight and cost of the yardarms.

Auxiliary Power-- Beginning at TL-4, auxiliary power sources may be added. These can include steam engines, internal combustion engines, batteries, fuel cells, or solar cells. Calculate the amount of auxiliary power needed for the desired speed while using the "iron breeze" and determine the weight and volume of the auxiliary power plant. Finally, calculate the auxiliary's endurance, fuel requirements, and range. Be sure to include sufficient fuel tankage for the required endurance and range. Remember, auxiliary power is needed to power any on-board electronics such as radios or sensors. This may be included in the form of wind generators, batteries, fuel cells, or solar cells if power is not desired for propulsion.

Step 2C: Muscle Power

Water craft may be powered by muscles as well as wind or machinery. Devices used to transfer muscle power to thrust include paddles, oars, and lever- powered screws.

Oars-- Oar locks allow oars to be used as mechanical levers that provide the most efficient way to transfer muscle power to propulsive thrust. Determining the amount of power generated by rowers is based on the species and skill of the rowers.

The basic value for any given species that is capable of rowing is 1/2 the species' average weight in kilograms. The average human weighs 70 kilograms. Therefore, the basic human rowing value is 35-- measured in watts of power produced by an individual human.

This basic wattage value is modified by ability. A rower's ability is determined by the total die modifier received for:

Strength Constitution Small Watercraft skill level

For each point of rowing ability, the rower is able to increase power output by 40% of the basic wattage value. As an example, an individual with Strength 7 (DM+1) and Constitution 7 (DM+1) has two points of rowing ability. Accordingly, the individual's basic wattage value is increased by 2 x 40% or 80%. This means that:

35 basic wattage x 1.8 = 63 watts of total power.

Note that well-trained, highly fit individuals can easily double this level of output. On the average, professional rowing crews can be assumed to produce two times the wattage of average individuals of a given species.

For reference, average for Vargr and Aslan rowers are given below:

Species Avg Mass Basic Wattage Avg Individual

Vargr 55 27.5 50 Aslan 100 50 90

Oar-powered water craft require allocating 100 kilograms weight for each human and each rower's oar. Allocate 150 kilograms for each rower and oar if the rowers are Aslan, or 75 kilograms if the rowers are Vargr. Alocate 2 cubic meters of volume for each human rower stationed below decks within the hull, 3 cubic meters for each Aslan, and 1.5 cubic meters for each Vargr. Calculate the total power output by multiplying the individual rower's output by the number of rowers on board. Potential top speed may be calculated from the total power output.

Oars can have more than one rower to increase power. Each additional rower (after the first) adds 75% of his power to the oar. Each rower requires one meter of beam.

There is a limit to the number of oars that can be placed in a hull. Subtract twice the beam from the length of the hull in meters to calculate usable rowing space. Each oar in a bank of oars requires one meter within this space. Oars can be stacked to form more than one bank. Each bank requires one meter of height.

Oars weigh 10kg each and cost CR10 each.

Paddles-- Light water craft may be propelled with paddles. Though this is similar to rowing a vessel with oars, less power is transfered because paddles have no leverage. A paddle will transmit 60% of the power generated by a rower using an oar.

Paddles weigh 2 kg and cost CR10 each.

Muscle Engines: Mechanisms That Convert Muscle-Power to Useable Wattage

The following `engines' use muscle-produced wattage to power Marine Transmission systems .

Levers and Cranks: These devices are available at TL 3. They can only be used by sophonts, or creatures which can be trained to perform a repetitive, noninstinctual task. All workers re- quire at least Adequate crew positions. Species that are much larger or smaller than humans may have greater or lesser requirements.

Turnstiles/Treadmills: These devices are available at TL 1 and can be powered by any type of creature that has a movement rate of greater than `0'. All workers require 1 cubic meter per 10 kilograms of weight. So a human (average weight of 70 kg) would require 7 cubic meters of space.

Step 4: Pumps

All vessels leak at one or more points in their lives. Leaks may occur through damage, or through joints that gradually loosen, or through seepage. Water may also come aboard during heavy weather. Because of this, all vessels need pumps. Pumps aboard primitive vessels are muscle-powered. Pumps are mechanically or electrically powered on modern vessels . Be sure to install pumps with enough capacity to handle flooding in at least one large sealed compartment in case of damage.

Pumps are rated by the number of cubic meters they can pump per hour.

The Pump Table below gives the power required and the flow rate generated per cubic meter of pump volume at various tech levels. Pumps weigh one tonne per cubic meter. Power for TL2 and earlier pumps must come from muscle power at 35 watts per person.

MARINE PUMPS

TL	Power (MW)	Volume rate m3/hour
2-	0.005		4
3	0.005		5
4	0.01		10
5	0.01		15
6	0.01		20
7	0.01		25
8	0.01		30
9	0.03		80
10	0.04		90
11	0.04		100

Step 5: Superstructures

All surface vessels may have superstructures built on top of their hulls. Superstructures increase the total weight and volume of a vessel but do not add to its fluid displacement. Superstructures may range from small deck houses built aboard sailing vessels to massive structures almost the length of the vessel built to accommodate passengers aboard liners. Cargo vessels and warships generally have smaller superstructures-- generally not more than 20 to 30 percent of the hull's volume. To build a superstructure:

1. Determine the volume of the superstructure(s) in cubic meters.

2. Detemine the material volume (MV) of the superstructure by the following equation:
MV = (2x(superstructure height) x (superstructure length + superstructure width) + (superstructure length x superstructure width))/100
The minimum superstructure thickness should be 0.25 cm.

2. Convert these to tons in hull equivalent tonnage.

3. Determine the weight of the superstructure(s) by multiplying the tonnage with the weight modifier from the hull materials table.

4. Determine the price of the superstructure by multiplying the tonnage by the price modifier for the selected material from the hull materials table.

Note that the hull and the superstructure may be (and often are) built of different materials such as a wooden deck house on a steel hull.

Superstructures may be used for the ship's bridge, for passenger and crew accommodations, or to house additional cargo. Deck cargo, stowed in sealed containers and stacked on deck become a type of temporary superstructure on many cargo ships. More than one superstructure may be built. A common cargo ship design is the "three-islander" with a superstructure housing the deck crew above the bow, a mid-ship's superstructure housing the bridge and officers quarters as well as messing facilities, and an aft superstructure over the fantail housing the engine room crew.

Step 6: Controls

Unpowered primitive mechanical or basic mechanical (at TL5) controls are required for wet ships built in the context of World Tamers. Primitive mechanical controls cost MCr.0001 per displacement ton and basic mechanical controls cost MCr.0002 per displacement ton. All controls displace 0.014 cubic meters per displacement ton and mass 0.0014 tonnes per displacement ton.

Step 7: Crew

Powered Vessels

Calculate the number of crew members you need aboard your vessel. You will need crew members to stand watch on the bridge, as lookouts, and in engineering spaces.

Engineering
At least one crew member must be provided for each five kiloliters of power plant aboard a TL6+ powered vessel with a power plant of one kiloliter or greater. If the vessel is fueled with coal or wood, at least two crew members must be provided for each 5 kiloliters of power plant. If the vessel is to be underway for more than eight hours, enough engineering crew members must be provided to stand two four-hour engineering watches every 24 hours. The engineering department is supervised by a Chief Engineer. If more than one crew member is on watch, the senior watch stander is an Assistant Engineer.

Bridge
On merchant vessels, two senior officers, the Master and First Officer, plus an officer and crew member for each watch. Bridge crews (except for the Master and First Officer) typically stand two four-hour watches every 24 hours. A normal merchant bridge crew includes a crew member at the helm and a watch officer. The bridge crew is equivalent to the Command Crew in FF&S starship designs.

Deck Department
Minimum of three crewmembers to serve as lookouts on watch and handle maintenance plus one additional crew member per 1000 tons fluid displacement. A boatswain supervises the deck crew and their maintenance work. The Deck Department is equivalent to the Maintenance Crew in FF&S starship designs.

Steward
As detailed in Fire, Fusion, and Steel. Minimum of one if carrying passengers or if voyage is expected to last longer than 5 days.

Medical
As detailed in Fire, Fusion, and Steel. Minimum of one if carrying passengers or if voyage is expected to last longer than 5 days.

Primitive Vessel Crews

Oar-powered craft must have at least one crew member for each oar. Up to four crew members may pull on one oar. If the craft will be rowed for more than eight continuous hours, a relief rower must be available for each oar. Sail-powered craft must have one crew member per 100 square meters of sail in addition to the command crew, gunners, or ship's troops. Primitive gun crews must include one member per every 2 kilos of each gun's weight of shot; e.g., a gun firing an eight-kilo shot must have four crew members.

Step 8: Accommodations


Vessels which will house passengers and crew for more than 24 hours require extended acccommodations. Passengers require one small stateroom or may double up in a large stateroom. Crew aboard steam-powered vessels (TL4+) are accommodated two to a large stateroom while officers each have a small stateroom. In truly cramped vessels of TL 1-3 , a more basic type of extended accommodation is available: the half bunk. The half bunk is either a light frame double bunk, or hammock, with just enough space for the individual's gear and provisions.

               Pwr   Vol    Mass    MCr
Half Bunk      --     6     .25     .0025

All other accomodation ratings are the same as listed in FF&S.
Aboard primitive craft (TL-3 or lower) provide 200 kilos of weight per person. This provides for his hammock, personal possessions, and food and water for 30 days. Each person should have at least 1 kilo of food and 2 kilos of water per day, more if the weather is hot or the work is hard.

Step 9: Maintenance Points


Calculate Maintenance Points using the rule in FF&S.

Sample Wet Ship Designs


Here are four wet ship designs created using these rules. They are designed to be simply and easily constructed on a frontier world using local materials. They are made mostly of local wood. Their sails are fabricated from canvas that can be woven from plant fibers using TL3 textile processing equipment.
One powered vessel (the trawler) uses an internal combustion engine imported from off world, while the other (the riverboat) uses a simple reciprocating steam engine that can be fabricated in any TL4 foundry.
These profiles are similar to other TNE starship and vehicle profiles with one addtion: the bouyancy of the vessel expressed in tonnes of displaced water. If the loaded weight of the vessel exceeds the bouyancy value, the vessel sinks.

Trawler

General Data
Displacement:  20 tons	Hull Armor: 0
Length:  20	Volume: 280
Bouyancy: 140 tonnes
Cost: MCr0.34	Target Size: VS
Configuration:  Curved Hull	Tech Level: 5
Superstructure: 70m3
Mass (Loaded/Empty): 140/18.4)

Engineering Data
Power Plant: 200 kilowatt internal combustion, 30 day duration
Power Transmission: 0.5 meter screw propeller
Maximum Speed: 15 kph, 11.25 kph cruising.
Maintenance: 69

Electronics
Commo: 300 km Radio

Accommodations
Crew: 4 (1 x Engineering, 1 x Maintenance, 1 x Steward, 1 x Command)
Crew Accommodations:  4 x Small Staterooms
Cargo: 100 m3
Notes:  In trawler role, nets are carried as deck cargo and hold accommodates
ice and caught marine life.  This design may also be used as a small coastal
freighter.

Riverboat

General Data
Displacement:  50 tons	Hull Armor 0
Length: 28	Volume: 700
Bouyancy: 490
Cost: MCr1.88	Target Size: VS
Configuration: Parallel Displacement Hull	Tech Level: 3
Superstructure: 1400 m3 
Mass (Loaded/Empty): 299/68

Engineering Data
Power Plant: 500 kilowatt early steam reciprocating, wood fueled.
5 days duration with carried fuel supply of 72 m3  of wood.
Power Transmission: 5 meter diameter stern wheel.
Maximum Speed, 15 kph; Cruising Speed 11.25 kph
Maintenance: 296

Accommodations:
Crew: 34 (20 x Engineering, 4 x Maintenance, 8 x Command, 2 x Stewards,)
Crew Accommodations: 5 x Small Staterooms, 29 x bunks.
Passenger Accommodations: 30 x Small Staterooms
Cargo: 190 m3 
Note:  In this design, the hull functions as a bouyancy platform supporting
a large deckhouse, although some cargo and wood fuel is stored internally.
A large wooden deckhouse provides space for the crew and passenger
accommodations as well as the pilot house. The boiler and steam engine
are located directly on top of the hull within the first deck of the
superstructure.  This vessel is designed for service on calm waters such
as rivers and lakes.

Ketch

General Data
Displacement: 10 tons	Hull Armor: 0
Length: 21	Volume: 140
Bouyancy: 70
Cost:MCr0.43	Target Size: VS
Configuration: Curved Displacement Hull	Tech Level: 3
Mass (Loaded/Empty): 13.9/4.9

Engineering Data
Rigging:  2-masted fore and aft rigged sailing ship with 79m3 of sail area
on 12-meter high masts..
Speed:  The following chart shows the ketch's speed at various
wind velocities.


Maintenance: 10

Accommodations:
Crew: 6 (3 x Maintenance, 3 x Command)
Crew Accommodations: 1 x  Small Stateroom, 5 x bunks.
Passenger Accommodations: 1 x Small Stateroom
Cargo: 9 tonnes
Notes:  This is a small sailing vessel suitable for cargo hauling
and exploration, particularly among the islands of an archipelago
and in coastal waters.

Clipper

General Data
Displacement: 600 tons	Hull Armor: 0
Length: 75	Volume: 8400
Bouyancy: 4200
Cost:MCr2.88	Target Size: Small
Configuration: Parallel Displacement Hull	Tech Level: 3
Mass (Loaded/Empty): 4164/64.35

Engineering Data
Rigging:  3-masted full rigged ship with main mast height of 50 meters.
Total sail area = 2925 m3
Speed:  The following chart shows the clipper's speed at various wind
velocities.


Maintenance: 4164

Accommodations:
Crew: 36 (29 x Maintenance, 2 x Stewards, 5x Command)
Crew Accommodations:  1 x Large Stateroom, 4 x  Small Stateroom, 31 x bunks.
Passenger Accommodations: 4 x Small Stateroom
Cargo: 4100 tonnes
Notes:  This is a large cargo carrying sailing vessel suitable for long-haul
voyages between continents.  It has a limited passenger capacity.

®1997 by Terry McInnes. Traveller is a registered trademark of Far Future Enterprises. All rights reserved.