Seafarer's Place

A Seafarer's Pen

How To Get The Tropical Draft?

Tropical Draft is 1/48 above the Summer Draft.
1/48 = 0.02083
* Multiply
+ Add
- Subtract

Tropical Draft = Summer Draft + (0.02083 * Summer Draft)

Summer Draft = Tropical Draft - (0.02083 * Tropical Draft)

How to calculate the change of Ship's Draft?

To determine the Ship's Fresh Water Draft when coming from Sea Water to Fresh Water.

* = Multiply
/  = Divide

Draft in Fresh Water = ( Sea Water Density / Fresh Water Density ) * Sea Water Draft


To determine the Ship's Sea Water Draft when coming from Fresh Water to Sea Water.

Draft in Sea Water = ( Fresh Water Draft * Fresh Water Density ) / Sea Water Density

How to get the liquid cargo expansion?

Simple way to solve for liquid cargo expansion when heating or to avoid tank overflow when the the temperature will rise.

Expansion = (Higher Temperature - Lower Temperature) * 0.00075 * Volume of Liquid Cargo

How to get the New Cargo Density?

This is one of the simple ways to get New Density.
When loading two different cargoes with different densities into a same tank.

By scientific calculator or by microsoft excel worksheet.

* = Multiply
/  = Divide

New Density =((First Cargo Volume*First Cargo Density)+(Total Cargo Volume - First Cargo Volume) * 2nd Cargo Density)/Total Cargo Volume

How to get the Ship's New Displacement?

One way to solve the New Displacement.

* = Multiply
/  = Divide

New Displacement = (Old Displacement * New Density ) / Old Displacement