# Ship Handling /Pilotage question - Transverse Thrust

I’ve been studying for a pilots exam for sometime now and I’m stuck with one question I cannot find an answer to.
The question goes something like this:
You are berthing a 15,000SHP vessel with a left handed CPP propulsion system, what is the transverse thrust in tons of the propellor.

I know now how to calculate transverse thrust from thrusters, and how to calculate windage in tons but cannot find an answer to this question anywhere.

Any help would be appreciated.

General ship-handling theory accepts transverse thrust as about 10% of applied power astern, but with many variables, especially with CPP. With CPP, high RPM and low pitch results in much different transverse thrust than low RPM and high pitch.
For the purpose of your question, if you can assume that a Half Astern bell is actually half of the 15000 SHP, then 7500 HP is being applied astern, and transverse thrust should be about 750 HP, or 7.5 tons (100 HP = 1 ton).
The question is incomplete.

A standard transverse thrust percentage with astern bells is 5 to 10. Note that isn’t 5-10% of 15,000, but 5-10% of whatever bell you are using.

Say your dead slow astern is 1,500 HP. 10% of that is 150 HP. 150 HP is roughly 1.5 tons.

The Shiphandlers Guide is a good reference book, it used to be available on the internet but has been taken down.