MULTIHULL INSURANCE

 

 

 

 

 

Multi-hull ships (vessels, craft, boats) comprise a great variety of types, sizes and applications. At the present time, the main interests in shipbuilding and shipping industries of multi-hull vessels are focused on engine-powered ships. Today thousands catamarans are used as racing, sailing, tourist, fishing boats. Hundreds (about 70%) of fast passenger and car-passenger ferries are catamarans. About 300 semi-submersible drilling and auxiliary platforms are exploited in the sea. Some ships with outriggers are built, including the experimental ship “Triton” (UK) and the first and second sister-ships of the series of Littoral Combat Ships, USA . About 70 SWA ships of various purposes and displacement are built. According to 'monograph' the entire breed of multi hull ships can be classed by the number of hulls and by the mutual arrangement of the hulls which includes the shapes and sizes of the hulls.

A very specific and important sub-group of multihulls is Small Waterplane Area (SWA) multihulls, a twin-hull version if this subgroup is commonly known as SWATH = Small Waterplane Area Twin Hull.

 

 

    

 

   Fig.1                    and                         Fig.2        



Joint classification is seen in Fig.1 and Fig.2 showing some arrangements of hulls for conventional and SWA multihulls, both reproduced from.

Numbers in Fig.1 stand for: 1 – catamaran: two identical conventional hulls, 2 – the same with non-symmetric hulls, 3 – trimaran, with three identical symmetric hulls, 4 – the same with flat outer boards of side hulls, 5 – catamaran with shifted hulls, 6 – proa or a vessel with bigger main hull and smaller side added hull, an outrigger, 7 – ship with outriggers which is a triple-hull ship with its side hulls being significantly smaller than the central hull. Fig.2 shows a waterplane sections of SWA vessels, here the numbers stand for: 1 – twin-hull SWA ship, each hull consists from the under-water volume ("gondola" or "under-water volume" or "pontoon") and one long strut; the type was named as the first built ship: "duplus"; 2 – twin-hull SWA ship with two short struts at each hull, the type was named as "trisec", 3 – triple-hull SWA ship with identical hulls, was named as "tricore"; 4 – SWA ship with (two) outriggers, 5 – a vessel with a conventional central hull and SWA outriggers, 6 - a monohull SWA vessel with foils. Each type of multi-hulls differs from the other and from the monohulls. For example, a catamaran has a biggest transverse stability of all ships of the same displacement. A duplus has biggest transverse stability from all SWA ship types. A trisec can have smallest area of water-plane of all multihulls and monohulls of the same displacement. A catamaran with longitudinally shifted hulls and any triple-hulled ships can ensure the most favorable interaction of wave systems are generated by the vessel at speed. A ship with outrigger(s) (proa or trimaran in Western sense) can have smallest relative mass of hull structures. Engine-powered multihull terms. Sometimes, the term “catamaran” is applied to any ship or boat, which consists from two hulls. But a deeper understanding needs for more detail terminology. 

 

The other twin-hull ships are proa, duplus, trisec. The history of commercial catamarans began in the 17th century in England. Some separate attempts of steam-powered catamaran application were carried out up by the middle of the 20th century. But such ships need for better materials and more developed hydrodynamic for successful application. The second half of the 20th century was the time of wide and in the main successful application of various catamarans on the base of developed science. Sometimes the term “trimaran” is used for any triple-hull ships or boats. But a deeper understanding of ship type characteristics needs for more detailed definition the types. Than hereafter the term “trimaran” is used only for a ship or boat from three identical hulls of traditional shape (the definition is usually for Russian science since 70-th years.) The other triple-hull ships or boats are outrigger ship, tricore. The main own specificity of a trimaran is biggest from all possible interaction of wave systems are generated by hulls at speed. The interaction can be favorable and not favorable ones, in dependence from relative arrangement of hulls and relative speed. Today the built trimarans are absent, only there are some results of model tests and corresponded estimation of the power of the full-scale ships; the calculations show big enough possible advantages at a defined band of the relative speeds. A new type of super-fast vessel, the “wave-piercing” trimaran, WPT, is known as air-born unloaded (up to 25% of displacement)vessel, which can ensure twice bigger, as achieved today, speeds with a permissible relative power. Proa is a ship or boat from one hull and one outrigger (small side hull). 

 

The engine in the main hull is more convenient, evidently, but not obligatory one. A ship with one main hull of converntional shape and two side small hulls (outriggers) is named as "outrigger ship". The same type is named as "trimaran" in English language publications. SWA ship Each hull, which has smaller beam at the level of design water-plane, than below it, can be named as a hull with decreased - or small - water-plane area. But more often the term “small water-plane area hull” means a hull from the under-water volume (“gondola”) and one or more thin strut(s), which connect the gondola with the above-water platform. Any ship or boat, which consists from hulls of small water-plane area, can be named as “small water-plane area ship” or “SWA ship”. Any twin-hull SWA ship is named as “SWATH”. A triple-hull SWA ship is named as “tricore” –today without dependence from the number of struts on each gondola. A ship or boat from two hulls with one long strut on each hull was named as “duplus” (by the name of the first drilling ship of the type).Today the duplus are most spread type of built SWA ships. The term “trisec” is used for a twin-hull SWA ship with two struts on each gondola. A trisec can have a minimal area of water-plane, therefore, minimal motions in waves and higher effectiveness of motion control.

An outrigger ship can have the main hull, and/or outriggers of small water-plane area. Mutual arrangerment of hulls. The hulls are connected by the above-water structure, which is named as “platform” or “above-water bridge”. The structure can be watertight partially or as a whole, or can consist of separate frames. The distance between the hulls is named as “transverse clearance” and can be measured by various methods: between center planes of hulls or between the inner boards. The distance between the design water-plane and the bottom of the above-water platform (“wet deck”) is named as “vertical clearance”. The longitudinal distance between a triple-hull ship is named as “longitudinal clearance” and can be measured between the middles of hulls or between their fore perpendiculars. Specificity of multihulls. The difference of geometry defines some sufficient differences of ship characteristics. Some differences ensure some technical and exploitation advantages and disadvantages for ships of various purposes. All multihulls have the following common specificity: - Widest possibility of geometry variations; - Relatively bigger, than in the comparable monohulls, area of decks, upper and inner ones. - It means the possibility of relative bigger inner volume of watertight above-water platform, which connects the hulls. - Independence of transverse stability from single hull lengthening; the stability strongly depends from the transverse clearance. - It means a possibility of simple enough ensuring of transverse stability of any multihull type. - Besides, it means the possibility of a wide variation of hull lengthening for higher performance. - Higher non-sink-ability because of big enough volume of the above-water platform. - Higher safety and survivability of energy sources because of power engine dividing by parts are distant each from the other. - Relative bigger overall beam. - More or less higher (in the dependence of the multihull type) seaworthiness in the comparison with the monohull of the same displacement. All ships with small-water-plane area, SWA ships, have smaller motions of any kind and external wave forces and moments, except the case of sailing in following waves. All systems of motion mitigation are the most effective ones for SWA ships.

 


ADVANTAGES and DISADVANTAGES of MULTIHULLS

As follows from, the specificity of multi-hulls can be an advantage for defined purposes, as below. The greater range of geometric variability allows to designers wide possibilityes of characteristic optimization in accordance with practical needs; the possibility of lower wave-making resistance (as a sufficient part of towing resistance ) is a sufficient advantage for high-speed and fast ships; the towing resistance can be significantly decreased by a rational selection of hull aspect ratio (twin-hull ships) and arrangement of hulls to take the most benefits of the interference between the wave systems generated by each hull (triple-hull ships); significantly greater area of decks and volume of closed (including watertight) and open spaces for payload; as a result, a multi-hull vessel can be a preferred choice for shipping high-volume and light-specific-weight payload (passengers, automobiles, etc.); transverse stability is independent of the aspect ratio of any hull, but depends on the transverse distance between the hulls at degree two; as a result, the transverse stability can be comparable with longitudinal stability, or even exceed it in some cases; it means wider possibility of dimension optimization without any restrictions by the transverse stability; a possibility of increasing the non-sinkability of the vessel by providing watertightness to the volume of the above-water platform and its rational dividing by water-tight bulkheads; it means higher safety of all multi-hulls in a comparison with the monohulls; higher safety and survivability of power plant machinery due to greater variability of the safest accommodation of its main components; it means higher survivability of all multi-hulls, especially - of combat ones; higher seaworthiness means higher part of time of sailing, when all needed demands of passenger and crew comfort are fulfilled.

The main disadvantages of multi-hull ships, as compared to monohulls, are the following: 

 

* the wider overall beam of a multihull vessel is often a problem for conventional docking; 

* the relatively greater total wetted area increases the frictional component of water resistance of the vessel, and thus the total resistance at low speeds (though this may balance out if eliminating wave resistance significantly; 

* the weight of hull structures per ton of displacement is greater than that of monohulls; 

* assembly of a multi-hull vessel in a shipyard takes a wider area; 

* as a result, the construction cost and maintenance (in dry dock) can be greater - but careful design can actually decrease construction costs.

 

 

 

 

 

 

 

Marine & Boat Insurance Providers Table

 

Company

Type of Insurance

Website

24 hour dinghy insurance

Dinghy & Sailboard Insurance Immediate insurance premiums displayed by clicking onto the class of craft.

24 hour dinghy insurance

ABG

We've teamed up with Boatinsure.co.uk to provide our clients with a competitive online marine quote: DINGHY, SPEED BOAT, SMALL YACHT, CABIN CRUISER.

ABG

Affinity Insurance Brokers

Official Brokers to the Irish Sailing Association. Affinity Insurance Brokers, the premier source for insurance coverage and risk management advice for Ireland's sailing and fishing communities.

Affinity

Amilcroft

Cargo INSURANCE. Take advantage of capacity and services through the London market and other specialist insurers. Our arrangements include insurers able to write surplus lines in most of North America.

Amilcroft

Arden Insurance

Arden Insurance Services are able to arrange cover on all craft from the smallest of dinghies to the largest ocean going vessels. Discounts are also available for: RYA Qualifications, Policy excesses up to 1,000GBP, Craft in Marina Berths, Craft with alarms. Many of our standard policies include: Third Party Liability up to 2,000,000GBP, 12 Months in commission cover, Underwater Machinery Damage, Protected No Claims Bonus, Road Transit Cover, Legal Protection Cover.

Arden Insurance

Edwards & Associates

We offer marine insurance to cover pleasure boats such as yachts and cabin cruisers, as well as larger private boats. Whether you are looking for personal or commercial marine insurance, we have a large base of insurers who we use to make sure that you get the best possible deal: Personal and Commercial Marine Insurance.

Edwards & Associates

BC-Marine Inurance

Set the right course to solve your Marine Insurance Requirements. Marine Craft Insurance, Legal Protection, Foreign Travel, Boat SalesAccident & Medical, Loss Of Earnings, Marine Finance, Marine Tradesmen, Crew Liability, Instalment Plans, Boat Builders & Repairers, Public Liability, Recovery & Assistance, Product Liability. UK, Ireland, Scotland, Wales & the EU.

BC-Marine Inurance

Bishops

We have particular expertise in the following: International Marine, Cargo, Inland Goods in Transit, Hauliers Liability, Freight Forwarders Liability.

Bishops plc

Alfred Blackmore

Alfred Blackmore Group Ltd UK insurance broker specialising in bloodstock, classic car, construction, financial services, healthcare, international motor, marine, professional indemnity, reinsurance and special accident.

Alfred Blackmore

Blythin & Brown

Loughborough brokers provide online quotes for marine insurance, and also offer a full range of financial advice.

Blythin & Brown

Boatinsure

Marine insurance underwritten by Lloyd's of London. Discover what is covered by the policies, read the FAQs, get an online quote or claim online.

Boatinsure

Business.Insurance-Site.co.uk

Covers most commercial risks in the following industries: manufacture, motor trade, haulage supply, farms, shops, offices, clubs, pubs, hotels and marine (ONLINE APPLICATION FORM).

Business.Insurance-Site.co.uk

Craftinsure

German marine insurer provides boat-insurance services throughout Europe. Select a boat type, get a quick quote, and track a claim. 20% internet purchase discount.

Craftinsure

Newton Crum

Dinghy - Narrowboat - Motorboat - Sailboard- Yacht - Marine Insurance. FREE INSURANCE QUOTATIONS no charge or obligation. Dinghy Insurance, Sailboard Insurance, Inland Waterways Insurance, Yacht - Motorboat - Speedboat Insurance, Stolen Boat List.

Newton Crum

Engine Breakdown Cover Ltd.

Offers unique insurance policies for marine in-board engines.

Engine Breakdown Cover

Fairmont Insurance Services

Super Yacht Insurance for yachts in excess of $1 Million to over $125 Million. Coverage includes Liability, Loss of Charter, and Crew Personal Accident and Medical.

Fairmontinsure

Lucas Fettes & Partners

Marine Insurance: Hull and accessories of a vessel, passengers and worldwide cargo movements.

Lucas Fettes

Navigators and General

Navigators and General has been at the forefront of yacht and motorboat insurance since 1921 and has been the market leader in this field for over 70 years. Navigators & General is part of the Zurich Financial Services Group and Financial Ombudsman Service, providing policyholders with world-class security. Today, Navigators provides cover for vessels with a total value in excess of £750,000,000. Underwriting insurance for all types of leisure craft, from dinghies to £5,000,000 vessels, has provided us with the breadth of experience to understand even the most individual requirements.

Navigators and General

Giles Insurance Brokers

Marine Insurance. Dinghy, Power Boat, Yacht, Cabin Cruiser, Jet Ski, Charter Boat, Commercial Fishing Boat, Yacht Yard

Giles Insurance Brokers

SHW Group

Marine Cargo Insurance. Cover is arranged with specialist insurers and the individual policies are written to suit your business requirements including if required Warehousing for distribution during export or import.

SHW Group

LONHAM GROUP LTD

Freight legal liability for both UK and international domiciled companies. Freight legal liability insurance, Cargo insurance, Charterer's Liability insurance. Delegated authority to deal with claims matters relating to marine insurance.

Lonham Group

Mardon Marine Insurance Brokers

boat-insurance.co.uk and yacht-insurance.co.uk are the websites of Mardon Marine and maritime Underwriting Agencies Ltd. (Including Maritime Underwriting Agencies Ltd)

Mardon Marine

Noble Marine

Noble Marine are specialist insurance brokers dealing with all classes Yacht insurance, rowing insurance, laser class, dinghy insurance, sailboard insurance.

Noble Marine

Rob, Perry Marine

Need Insurance? We are agents for one of the most competitive insurance brokers in the country who specialise in marine insurance.

Rob, Perry Marine

Pendleton May

We operate a scheme for the insurance of yachts, motor boats and small craft. Our expertise, experience and number of clients insuring their boats enables us to provide you with wide cover at competitive cost. Try us by completing our form.

Pendleton May

Terra Nova

Terra Nova Protection & Indemnity provides fixed premium P&I cover for the Owner / Manager / Charterers of commercial ships operating in domestic, coastwise or short-sea trades.

Terra Nova

Oban Insurance Centre

Read about the insurance schemes covering marine, holidays, business, motoring and agriculture. Offers an online quote system.

Oban Insurance

B Portwood & Co.Ltd

Marine and boat insurance. On-line insurance rates are provided for dinghies, canoes, sailboards, small craft, inflatables, speedboats, yachts and motorboats for use in the uk and in Western Europe for up to 60 days.

Portwood

Alexander Brooks & Stevens Ltd

Marine Insurance providers

Alexander Brooks & Stevens

Graham Sykes Insurance

Graham Sykes Insurance insure a variety of boats. Our polices cover you for use on inland and costal waterways between May and September. Smaller craft usually have to be laid up ashore over the winter months. For larger vessels we can provide cover for them all year round. For the water skiers out there we can usually extend your policy to include liability for towing water skiers.

Graham Sykes

Craig & Suttar

In most cases we can provide all risks cover including third party liability for you and your craft. Polices cover you for use on inland and costal waterways between May and September. For the waterskiers out there we can usually extend your policy to include liability for towing waterskiers. In some case we can add your boat onto your house contents insurance which is sometimes cheaper.

Craig & Suttar

Tyser (UK) Ltd

Marine and boat Insurance

Tyser (UK) Ltd

Yachtsman Marine Insurance Ireland

Yachtsman Marine Insurance Ireland. Sports boats, Yacht cruisers, motor cruisers. We offer yachtsmen an exceptional insurance package at a highly competitive price. We are constantly reviewing our policy wording to provide the most up to date terms and conditions to ensure that our clients have the most appropriate cover.

Yachtsman Insurance

 

 

 

 


 

 

 

 

 

 

 

Meeting Your Needs 

Offering a range of services to most business sectors the providers below specialise in insurance design, risk placing and risk management for UK and international concerns.

They have considerable experience in the development of solutions for both Marine and Commercial risks. With access to Lloyds of London and a range of ABI registered Insurers they can secure the most competitive premiums and terms.  All of the above is a very good reason to click through from us to obtain your online quotation, and it doesn't cost you a penny more to do so. 

 

 

LINKS

 

http://www.mocra-sailing.co.uk The Multihull Offshore Cruising & Racing Association

http://www.catamaran.co.uk/main.htm The UK Catamaran Racing Association

http://www.mycq.org.au/ The Multihull Yacht Club of Queensland (Australia)

http://multihullboatbuilder.org Multihull Boatbuilding Information / Community

http://www.multihull-maven.com Articles and news on multihulls, profiles of boats, designers, yards, etc.

http://www.sailing.org International Sailing Federation

http://www.multihulls-world.com/us/ The multihulls reference magazine

http://www.multihull.com.au The multihulls reference magazine (Australia)

 

 

 

 

 

 

INTERNATIONAL MARINE INSURANCE BROKERS - LONDON - POWER and SAIL BOAT INSURANCE, YACHT INSURANCE, LINERS, CARGO INSURANCE, CONTAINER SHIPS, TRAWLER INSURANCE, RIBs, OIL TANKERS and MORE - CLICK THIS LINK FOR DETAILS AND A QUOTATION

 

 

 

 

Laser weapons on boats are now a reality

Fleet operators might reduce insurance costs if their ships have

autonomous capability, which system promises safer seas.

 

 

 

 

 

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