Editing Ship model (section)

== Scale conversion factors ==

{| class = floatright border="1" cellpadding="2" cellspacing="0" align="right"
|+ Table&nbsp;of&nbsp;Scale&nbsp;Conversion&nbsp;Factors
|-
! from
! to 1/8
! to 3/16
! to 1/4
|-
| 1/16
| 2.0
| 3.0
| 4.0
|-
| 1/12
| 1.5
| 2.25
| 3.0
|-
| 3/32
| 1.33
| 2.0
| 2.67
|-
| 1/8
| 1.0
| 1.5
| 2.0
|-
| 5/32
| 0.8
| 1.2
| 1.6
|-
| 3/16
| 0.67
| 1.0
| 1.33
|-
| 1.5
| 0.625
| 0.94
| 1.25
|-
| 7/32
| 0.57
| 0.86
| 1.14
|-
| 1/4
| 0.5
| 0.75
| 1.0
|}

Instead of using plans made specifically for models, many model [[shipwright]]s use the actual blueprints for the original vessel.
One can take drawings for the original ship to a blueprint service and have them blown up, or reduced to bring them to the new [[Scale (spatial)|scale]].
For instance, if the drawings are in 1/4" scale and you intend to build in 3/16", tell the service to reduce them 25%.
You can use the conversion table below to determine the percentage of change. You can easily work directly from the original drawings however, by changing scale each time you make a measurement.

The equation for converting a measurement in one scale to that of another scale is '''D2 = D1 x F''' where:

* D1 = Dimension in the "from-scale"
* D2 = Dimension in the "to-scale"
* F = Conversion factor between scales

Example: A yardarm is 6" long in 3/16" scale.  Find its length in 1/8" scale.

* F = .67 (from table)
* D2 = 6" X .67 = 4.02 = '''4"'''

It is easier to make measurements in the [[metric system]] and then multiply them by the scale conversion factor.
Scales are expressed in fractional inches, but fractions themselves are harder to work with than metric measurements.
For example, a hatch measures 1" wide on the draft.
You are building in 3/16" scale.
Measuring the hatch in metric, you measure 25&nbsp;mm.  T
he conversion factor for 1/4" to 3/16', according to the conversion table is .75.  So 25&nbsp;mm x .75 = 18.75&nbsp;mm, or about 19&nbsp;mm.
That is the hatch size in 3/16" scale.

Conversion is a fairly simple task once you start measuring in metric and converting according to the scale.

There is a simple conversion factor that allows you to determine the approximate size of a model by taking the actual measurements of the full-size ship and arriving at a scale factor.
It is a rough way of deciding whether you want to build a model that is about two feet long, three feet long, or four feet long.

Here is a ship model conversion example using a real ship, the Hancock.
This is a frigate appearing in Chappelle's "History of American Sailing Ships".
In this example we want to estimate its size as a model.
We find that the length is given at 136' 7", which rounds off to 137 feet.

{| class = floatright border="1" cellpadding="2" cellspacing="0" align="right"
| 1/8 scale
| Feet divided by 8
|-
|-
| 3/16 scale
| Feet divided by 5.33
|-
|-
| 1/4 scale
| Feet divided by 4
|-
|}

To convert feet (of the actual ship) to the number of inches long that the model will be, use the factors in the table on the right.

To find the principal dimensions (length, height, and width) of a (square rigged) model in 1/8" scale, then:

# Find scaled length by dividing 137 by 8 = 17.125"
# Find 50% of 17.125 and add it to 17.125 (8.56 + 17.125 = 25.685, about 25.5)
# Typically, the height of this model will be its length less 10% or about 23.1/2"
# Typically, the beam of this model will be its length divided by 4, or about 6 1/2"

Although this technique allows you to judge the approximate length of a proposed model from its true footage, only square riggers will fit the approximate height and beam by the above factors. To approximate these dimensions on other craft, scale the drawings from which you found the length and arrive at her mast heights and beam.