# Ship Berthing Energy Forces On Piles / Fenders

1. Apr 11, 2014

### tayre89

I am looking into the forces as a result of berthing energy from a ship on a pontoon. The situation i am looking at is a simple pontoon of about 10 m long with mono piles on each end.

I am assuming a ship impacts the pontoon at mid span between the piles.

The pontoon has fendering on its berthing face that has the potential to deflect 0.2 m as a result of berthing impact.

My problem which i cannot get my head around is that the formula I am using (See below) gives me a berthing energy in Kn M.

1 - How can i translate this KN m so as i can get a force so i can then translate these forces into the piles to check that they can resist the load

2 - How do i calculate the reduction in force as a result of the deflection of the Fenders ?

The equation i am using for berthing impact is as follows:

0.5 x Mass x Velocity 2

My Attempt

Mass = 5000 kg
Velocity = 2 m/s

Force
= 0.5 x 5000 x 2
= 5000 kg.m

From this point onwards I cant get my head around how this kg * value will translate into a force.

3. The attempt at a solution

2. Apr 11, 2014

### nvn

tayre89: The force applied to the pontoon midspan would be, P = m1*(v1^2)/y, where m1 = ship mass, v1 = ship velocity, and y = pontoon deflection. Give it a try.