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PONIŠTENJE POSTUPKA NABAVE

 Datum objave: 28. travnja 2017.

PONIŠTENJE POSTUPKA NABAVKE ŽELJEZNIČKIH VAGONA ZA PRIJEVOZ KONTEJNERA HLADNJAČA S MOGUĆNOŠĆU NAPAJANJA ELEKTRIČNOM STRUJOM

Poništava se postupak javne nabave željeznidkih vagona za prijevoz kontejnera hladnjača sa mogućnošču napajanja električnom strujom, objavljen na mrežnoj stranici Naruditelja dana 5. travnja 2017. godine.


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Underwater hull cleaning and propeller polishing

Definition

uwshHull-cleaning, involves the removal of all types of biological fouling on the boat underwater hull and underwater devices, using brushes, scrapers and similar tools, in order to maintain proper antifouling protection and to preserve underwater parts of the boat.

Introduction

Underwater hull cleaning and propeller is closely connected with the intention of boat owners to maintain quality antifouling protection.
Good antifouling protection ensures optimum fuel consumption by reducing water resistance, as well as the protection of painted metal parts of the boat.
Unpainted underwater parts and devices such as propellers, are prone to fouling and they need additional attention in regular boat maintenance.

Why?

Reducing the engine fuel consumption;
Extended life of antifouling paints;
Extended life of natural uncolored parts - wear of the propeller;
Extended life of sea water cooled engines;
Successful control of the boat hull at regular intervals;

When?

Periodically;
Occasionally;
As needed.

Where?

Cargo loading/ unloading
At anchor.

How long?

Hull = 800 - 1600 m² / h
Propeller = 4-6 hours

PROCEDURE AND INSTRUMENTS

Checkup before cleaning - determining the condition of fouling, type of cleaning and tools needed;
Cleaning - hydraulicaly driven devices operated by divers - CCTV supervision of all activities;
Checkup after cleaning - written reports with digital photographs;

DEGREE OF HULL FOULING

Light - preserved antifouling paint, rare and poorly adhered fouling;
Medium - preserved antifouling paint, very thick fouling adhered;
Heavily - damaged antifouling protection, heavy to very heavy fouling, very
adhered, calcareous organisms penetrated to the metal structure.

TYPES OF CLEANING

Complete cleaning - entire hull, all painted parts, propeller, inlet ports, propeller shafts and hull openings;
Partial cleaning - selected parts of the hull (for example one third of the hull, two thirds of the hull...), additional devices, opennings and inlet ports, propeller;
Temporary cleaning - propeller, propeller shafts, rudder.

 
PROPELLER POLISHING

"In absolute terms, the propeller surface condition has less importance than the hull surface condition, but it has a significantly greater impact in energy loosing terms at the hull surface. In economic terms, the relatively small investment in maintaining the propeller gives high results "
                               
Mossad, M. "Marine propeller roughness penalties"
Ph.D.Thesis, University of Newcastle upon Tyne, 1986.

PROPELLER WEAR

Corrosion;
Cavitation;
Bio fouling;
Improper maintenance.

POLISHING THE PROPELLER

Hydraulic tools;
Extremely fine abrasives;
Achieving Level B or C (Rupert scales).

BENEFITS

Underwater hull cleaning and polishing the propeller while the boat is in the water;
Underwater hull cleaning and propeller polishing during the cargo loading / unloading Underwater hull cleaning and propeller polishing postpones going to the dry dock;
Underwater hull cleaning and propeller polishing allows higher frequency of maintenance;
Underwater hull cleaning and propeller polishing enables faster identification of parts wearing

ULTRASOUND INSPECTION

Steel measurement: 3-250 mm
Accuracy: ± 0.1 mm or ± 0.05 mm;
No cleaning up to 6mm layers;
Accepted by all the leading certification companies.