## BASICS

Study Target and Basic Data

__GOAL:__Calculation of weight saving potential by using ISOVER ULTIMATE insulation products instead of traditionally used stone wool products in the shipbuilding industry.

**BASIS FOR THE STUDY:**Large RoRo Passenger Ferry with cabins, public areas, and one car deck

Length over all 210m

Length between perpendiculars 195m

Beam 29m

Draught 6,4m

Passenger 2800m

Passenger cabins 900m

Passenger public decks 2

Passenger cabins decks 4

Car decks 1

**RESULT:**280 tons on weight savings with ULTIMATE

## FUEL CONSUMPTION

280 tons weight savings means:**DECREASE IN FUEL CONSUMPTION**

With a bunker price of 700 $, savings scenarios display as follows:

**USAGE OF THE RORO PASSENGER FERRY WITHIN**

**10H/DAY AND 340 DAYS/YEAR**in 24 knots savings are 272 t -- -- -- -- 191.000 $

in 22 knots savings are 170 t -- -- -- -- 119.000 $

in 19 knots savings are 136 t -- -- -- -- 90.000 $

**15H/DAY AND 340 DAYS/YEAR**in 24 knots savings are 408 t -- -- -- -- 286.000 $

in 22 knots savings are 255 t -- -- -- -- 179.000 $

in 19 knots savings are 204 t -- -- -- -- 143.000 $

**20H/DAY AND 340 DAYS/YEAR**in 24 knots savings are 544 t -- -- -- -- 381.000 $

in 22 knots savings are 340 t -- -- -- -- 238.000 $

in 19 knots savings are 272 t -- -- -- -- 191.000 $

## CHANGING DEAD LOAD INTO PAYING LOAD

280 tons weight savings means:Savings can be used directly for increasing dead weight by 5,4 %. 280 tons approximately equal 6 trailers of 45t each.

Alternatively the gained deadweight capacity can be used for bunkers, grays, water holdings, etc...

## Building costs

280 tons weight savings means:

**SUBSTITUTION OF ALUMINIUM STRUCTURES**The reduced lightship weight and the decrease of the gravity center enable the subsitution of the aluminium structures, if used, with cheaper steel structures. In the present case, a 150 tons of aluminium structure located on the deck can be replaced by an equally sized steel structure of 250 tons.

Costs savings add up to approximately 1.860.000 $.

**ADDITIONAL SUPERSTRUCTURE ON UPPERMOST DECK**Additional superstructure of 100 tons (corresponding to 450 m² deck area in steel structure or 560 m² deck area in alu structure). Total lightweight is in addition reduced by 180 t.

**OR**Additional superstructure of 175 tons (corresponding to 800 m² deck area in steel structure or 1000 m² deck area in alu structure. Rise in vertical centre of gravity has to be compensated by 105 tons additional ballast in double bottom.

## CO² and NOx REDUCTION

280 tons weight savings means:

**HFO FUEL**The usage of one ton of HFO fuel means approximately 3t of CO² emissions.

As a result of the calculation with 255 t savings (15h shipping on 340 d/year with a speed of 22 knots), that represents a reduction of more than 750 t CO²/year.

It will have an influence on the NOx emissions as well.

## STABILITY

280 tons weight savings means:**GRAVITY CENTRE DECREASE**

The weight reduction of 280 tons decreases the center of gravity of the lightship by approximately 10 cm.**VERTICAL CENTRE OF GRAVITY DECREASE**

In addition if the stability is critical, the mass of 280 t can be added in the double bottom, resulting in an additional decrease of the vertical centre of gravity by 20 cm.**DRAUGHT**

If the weight reduction is not compensated in any way, the decreased draught also increases stability margin.

ADDING OF WEIGHT WITHOUT CHANGING STABILITY MARGIN

Assuming that the weight of insulation is decreased by 280 tons and the center of gravity of the lightship is reduced by 10 cm due to the lighter insulation.

The graph shows how much weight can be added at a certain weight: