SELF PROPULSION TEST

Group members:Ahmad Shah Heermie

Mohd YushairieFadhlul HafizMohd Farid

Muhammad ShafieMuhammad Fareez

Kenny LingOng Shu Hoa

OBJECTIVESTo determine the propulsion requirements of a tanker model No. 7698 (MTL001)

TASK1) Describe fully the experimental set-up and the procedures used.2) Compare the results obtained using the adopted procedures used.3) Compare the resistance values obtained to that of bare hull.4) Comment on suitability of the procedure adopted and give suggestions on

further improvements required.

INTRODUCTION

For self propulsion test the model scale should be chosen so that the ship model as well as for the propeller model the critical value of Reynolds’ number is exceeded.

However, the development of the methods of generating turbulent flow artificially now permits satisfactory resistance tests to be carried out wit models of 1.5m length.

INTRODUCTION(contd..)

With a ship model of the size, however, it is still impossible to carry out a proper self-propulsion test.

According to the experience gained by the NSMB (MARIN), the minimum length of the ship models with reliable self-propulsion test can be carried out is approx.

2.5m.

APPARATUS Towing tank Resistance dynamometer Tanker model no. 7698 (MTL001) Data Acquisitions and Analysis System (DAAS) Sensors (transducer) Self-propulsion equipment

I. Propeller

II. Motor

III. Controller

Towing tank the basin are

# 120m length# 4m width# 2.5m depth.

# useful length = 90m maximum carriage speed = 5m/s

Carriage Sizes :

Distance between rail = 4.45 m Distance between wheel axles = 6.80 m Carriage net weight = 18 ton Material = Steel Wheels (diameter) = 800 mm Guide wheels (diameter) = 300 mm

Carriage drive system

Speed range : 0.1m/s to 5m/s Maximum acceleration : +1.0m/s2 Maximum deceleration : -1.0m/s2 Deceleration emergency off (disk and air brake) are

approx. -2.0m/s2 Railshoe emergency braking are approx. -5.0m/s2 Adjustable by means of a keyboard placed on the

control desk

TheoryTheory

Self propulsion tests are out to estimate ship power at various speeds and to derive propulsion factors Wt, t, CR.

METHODS:METHODS:

The hull model is equipped with an electrical motor mounted inside the hull and respective devices (dynamometer).

The size of the propeller unit model for propulsions test is determined automatically by the size of the ship model and its scale ratio.

An external tow force in propulsion experiment should be applied along the same line of action.

The three procedures for the self propulsion tests are available is: Load varying (or constant speed) method Constant loading method Mixed loading method 

1. Load varying (or constant speed) method

each test the model speed and the desired propeller loading should be selected repeat runs at the same speed should be made at different loading.

The loading range should extend from the lowest to the highest load factors

It is further recommended that, in all cases, the loading should cover the condition of model self propulsion.

2. Constant loading method

each test the model speed should be selected and the corresponding external tow force at the set loading computed.

The computed skin friction correction force (FD) is then applied to the model hull as an external assisting toe force which will be kept constant for all tests.

Repeat runs should be made at each of several speeds. The speed range should extend from the lowest to the speed range at

least 5% below

3. Mixed loading method

Combination of the load varying and constant loading methods may be used. For example, a speed variation at constant loading may be used, together

with a supplementary load-variation test at one speed.

Analysis of Propulsion Factors

Thrust, torque, rate of rotation and speed of hull are measured during self propulsion tests.

These values are used to derive propulsion factors. The analysis can be carried out in two ways:

1. Thrust Identity Analysis

Advance coefficients, JP are obtained from self propulsion test and the corresponding thrust coefficients KTP are calculated.

From the open water diagram at the same thrust coefficient, KTP corresponding JOT, KQT and COT are read off.

To determine the speed of the model.

To determine the thrust coefficient of the model,

To determine the torque coefficient of the model,

Vs

Vm

To determine the thrust of the ship,

To determine the torque of the ship,

42DnKT sTs

52DnKQ sQs

Experiment Data

Ship Model Length between perpendiculars, LPP 100.00 m 3.132 m Length on waterline, LWL

101.66 m 3.184 m Length overall submerged, LOS

104.98 m 3.288 m

Breadth moulded on WL, B 17.50 m 0.548 m

Draught moulded on FP, TF 6.65 m 0.208 m

Draught moulded on AP, TA 6.65 m 0.208 m

Displacement volume moulded, V

8702 m3 0.2673 m3

Displacement mass in seawater, Δ1

8919 t 0.274 kg

Ship Model

Wetted surface area bare hull, S

2513 m2 2.465 m2

Wetted surface with appendages, S1

2550 m2 2.501 m2

LCB position aft of FP, FB

49.05 m 1.536 m

Block coefficient, CB 0.747 0.747

Midship section coefficient, CM

0.995 0.995

Prismatic Coefficient, CP 0.751 0.751

Length-Breadth ratio, LPP/B

5.741 5.714

Breadth-Draught ratio, B/T

2.632 2.635

Scale ratio, λ = 31.93

Tank’s water temperature, T (C˚)

27.0

Tank’s water density, ρM (kg/m3)

966.4

Tank’s water kinematics viscosity, VM (x 10-6 m2/s)

0.85409

Standard value for tank properties.

Particular of the propeller represented by propeller model No. 6459

Diameter D 4400mm

Pitch at root - 3655mm

Pitch at 0.7R P0.7 3655mm

Pitch at blade tip - 3655mm

Pitch ratio at 0.7R P0.7/D 0.831

Boss-diameter ratio d/D 0.193

Expanded blade area ratio AE/A0 0.581

Number of blades 4

Figure 1

PROCEDURE

Load Varying Test. Set up the experiment as Figure 1: The towing carriage should be accelerated

from rest and simultaneously the propeller rate of revolution increased also from rest.

A short period will then normally be allowed before measurements are begun.

Repeat runs at the same speed should be made at different loadings and the whole series of runs then repeated at each of the speeds within the test range.

Speed Varying Test Before beginning each test run the model

speed should be selected.

Measurements are then made after a period of steady running. Repeat runs should be made at each of several speeds.

WEIGHT (kg)

LOAD

(N)

RPM Tm

(N)

Qm

(Nm)

Fm

(N)

266.34 2612.8

271.34 2661.8

276.34 2710.9

281.34 2759.9

286.34 2809.0

Load varying (design speed, 14knots constant)

Initial Value of Weight = 266.34kgAdding weight = 5kg

Ship Speed(knots)

Model Speed(msˉ¹)

RPM Tm

(N)

Qm

(Nm)

Fm

(N)

14 1.274

15 1.364

16 1.455

18 1.637

20 1.819

Speed varying (Load constant)

Initial Value of Model Speed = 1.274 m/s