Ships and Offshore Structures Repair / Maintenance

Rebuild rudder pintle housings

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Problem: The tapered section of the rudder pintle is located within a tapered gudgeon (housing) and is usually manufactured from a different material to that of the gudgeon. (Stainless Pintle, Steel Gudgeon) In service the whole assembly is immersed in water and as a consequence the gudgeon is damaged by galvanic corrosion, gradually becoming oversize.

Belzona Solution: The conventional solution would be to lay down weld metal onto the internal surface of the gudgeon and then machine it back to size; a very time consuming and expensive solution; the other downside of course is that this repair method doesn’t prevent the problem from reoccurring. The alternative Belzona solution is much quicker and far less expensive since the pintle itself is used as a former to rebuild the housing and the resultant repair will ensure that the same problem will not reoccur.

Belzona Know-How also extends to cover:

• Fair hull sections.
• Repair fiberglass hulls.
• Rebuild and protect stabilizer fins.
• Rebuild and protect hydrofoil leading edges.
• Rebuild and protect propeller strut assemblies.
• Rebuild and protect rudders.
• Sleeve rudder pintles.
• Rebuild bushing and bearing housings.
• Repair rubber flotation chambers.

• Rebuild and protect propellers.
• Rebuild and protect kort nozzles.
• Rebuild and protect bow and stern thruster tubes.
• Rebuild and protect hovercraft fan blades and pylons.
• Rebuild and protect jet propulsion systems.

Problem: The underwater structures of a vessel such as, kort nozzles, thrusters and shaft support pylons (“A” Frames) suffer from erosion-corrosion in the form of abrasion, cavitation and galvanic and/or biological forms of corrosion. Conventional repair usually consists of replacement or weld and machine options.

Belzona Solution: The Belzona® 1000 Series Metallic Polymers Ceramic systems are ideal for both restoring the original profiles of equipment and resurfacing the equipment in order to provide long term protection from the prevailing erosive- corrosive forces. Many of these repair procedures are specified by various international classification societies, such as ABS, DNV and GL.

• Rebuild stern tube housings.
• Rebuild propeller shaft flanges.
• Rebuild and protect propeller shafts.
• Seal variable pitch propeller hubs.
• Repair hovercraft skirts.
• Cast cutlass bearings.

Seal around deck machinery

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• Shim deck machinery.
• Seal hatch covers and manways.

Problem: Usually the base of any piece of machinery is flat - something which can not be said of the deck of a ship which is cambered from the ships centre line down to the gunwales. Consequently there is a requirement to ensure correct load transmission from the machine to the deck plating. This requires the gap between the machine and the deck to be filled.

Belzona Solution: Belzona 1000 Series Metallic Polymers do not contain solvents or VOCs (volatile organic compounds), which means that they do not shrink when they cure. Consequently they can be injected between the machine and deck to fill the gap, thus ensuring 100% contact between the two. The excellent compressive strength of these products ensures reliable and adequate load bearing capability.

Seal water-tight doors

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• Seal sectional helicopter landing decks.
• Caulk and seal wood decking.

Diagnosis: When liquids penetrate the gap between two components the result is often a form of accelerated corrosion known as crevice corrosion. Alternatively there may be a requirement to keep a liquid or gas confined within a piece of machinery for reasons of safety.

Belzona Solution: The Belzona 2000 and 3000 Series products can be used to provide a versatile range of sealing solutions which can be customized to suit a large range of applications. Being brush applied they can follow any contour and since the products will bond to most substrates they have the ability to provide reliable long term sealing solutions under many conditions.

Create safety non-skid surfacing

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Problem: Health and safety has become an extremely important part of our lives in recent years and there is no reason to believe that this will not continue. Personal and Personnel safety is vital and hazardous work areas due to slippery surfaces will not be tolerated now or in the future. Many conventional solutions to this problem have been found wanting due to premature wear out, loss of bond to the substrate or the fact that they can not be cleaned without sustaining some level of damage.

Belzona Solution: Belzona non skid systems are proven to provide long-term positive grip in many hazardous areas. They can be applied quickly and easily to virtually all substrates and will tolerate high pressure washing and even steam cleaning with out damage. Many different grades are available and thus the system can be tailored to the environment in which it must operate.

Repair damaged cable insulation.

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• Insulate and pot electrical connections and passages

Problem: When the outer cover of an electrical cable, in particular high voltage cables, or rubber hose, becomes damaged due to impact or abrasion, the inner layer of metallic reinforcement becomes exposed. Once exposed to moisture it will soon begin to corrode and at this point the cable must be renewed for health and safety reasons.

Belzona Solution: With regular inspection of these items small areas of damage can be repair as soon as they occur and the life of the equipment extended as a result.

Rebuild and seal evaporators

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Problem: Predominantly heat exchanger tubes are manufactured form a different metal than the tube sheet. This leads to bi-metallic corrosion at the junction of tube and tube sheet which in turn causes leakage across the tube sheet.

Belzona Solution: Because Belzona products are electrically non-conductive they can be used to isolate the two differing metals from the electrolyte thus breaking the electrical connection and thereby eliminating the galvanic corrosion.

 

Other auxiliary machinery application opportunities utilizing Belzona Know-How include:

• Rebuild and protect sea chests.
• Protect process vessels.

Repair seal fenders

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• Repair and seal floating hoses.

Problem: By the very nature of the job they do, fenders and hoses are subjected to impact, abrasion and wear. As a result punctures are common and can not easily be repaired by conventional means such as the hot vulcanizing process, which is time consuming, expensive and not always successful.

Belzona Solution: Belzona 2000 Series Elastomers have been proven to produce cost-effective reliable repairs. Whether the requirement is to bond, seal or rebuild, the Belzona 2000 Series will do the job.

• Rebuild and fair mooring bits.
• Rebuild power blocks.

Repair and protect: sand filters, de-aerators, seperators, coalescers, and de-gassers

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• Rebuild and protect cargo pipes.
• Reinforce tank bottoms.

Problem: Since cargo equipment and related systems are made of metal and are handling and processing fluids they are subjected to the ravages of erosion and corrosion.

Belzona Solution: Belzona 1000 Series Systems can slow down the effects of erosion and completely eliminate the effects of corrosion thus increasing the maintenance intervals and extending the overall operating life of the equipment.

Rebuild and protect di-chlor injection tee pieces

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Problem: These pieces of equipment operate where fluids in the system are at very high pressures are therefore subjected to the ravages of erosion-corrosion.

Belzona Solution: Belzona 1000 Series Systems slow down the effects of erosion and completely eliminate the effects of corrosion thus increasing the maintenance intervals and extending the overall operating life of the equipment.

Protect thermal insulation

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Problem: Conventional protection for thermal insulation is invariably accomplished by the use of metallic cladding. Unfortunately metallic cladding by nature must have many joints and seams and these allow ingress of fluids into the insulation. The result is Under Insulation Corrosion (UIC). On steel pipework the result is rust, while stainless steel pipework would suffer from Stress Corrosion Cracking (SCC), particularly in the presence of chloride ions.

Belzona Solution: Belzona 3211 (Lagseal) is a water-based product which can be applied to any type of thermal insulation material to form a seamless monolithic finish that will not allow any liquid to penetrate the insulation layer. The system itself is micro-porous thus, any moisture trapped within the insulation layer will dry out though the membrane ensuring that the insulation stays dry thus preventing the onset of Under Insulation Corrosion.