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Information and Technical Forum ..................

MARITECH is inviting interested parties for a joint venture to

build and operate a fast ferry service

between San Diego to Catalina island. The proposed ferry will be based on Maritech's 340 passenger capacity catamaran fast ferry design. The vessel will be an US built all-aluminum hull with waterjet propulsion and designed in accordance with with the latest Classification Rules of ABS or LR. Maritech has completed the preliminary design. Initial investment will be required. Economic analysis for ROI has been completed which indicates a pay-back period of 5 years (conservative projection) from venture capital. For more detail - please contact Maritech Corporation.

MARITECH recently completed redesign of deck superstructure to accommodate a crew of 6 and addition of main mast and cargo booms for a 235 ft fishing vessel for operation offshore San Diego.

MARITECH has recently developed a electronic Roll-Pitch indicator instument (RPI) to measure vessel's roll and pitch angle in static or dynamic environments. The unit can be mounted at any location of the ship and typically is connected to a Laptop to measure hull's angular displacements. The data samples are taken at 50+ measurements/sec (user's selectable) and results are displayed for average values on a virtual instrument on the screen. Maritech also has successfully used this RPI for static stability tests (Inclining Experiment) in liue of conventional pendulums, as well as for the roll tests. For more information about the RPI, please contact Maritech Corporation.

MARITECH recently completed recalculation of tonnage for a 44 m Tuna Seiner of French design. The reanalysis involved converting old tonnage (1947 Convention) to ITC-69 (1969 Convention) tonnage which resulted a net reduction of 25% in Gross Tonnage and 53% in Net Tonnage.

MARITECH has completed design of a 146 ft. Tuna Seiner. The vessel hull structure design is based on ABS rule scantlings for steel ships under 200 ft. (61 meters). Please watch for more details in the forthcomming update of this page.

MARITECH has developed a design using ARMY LCMs (salvage) to carry over 200 day passengers and operate as tour boats in protected waters. The design is based on LCM-8 Landing Craft, all steel construction with twin or quad diesel engines and relocated operator station. The seating is in two levels. The forward landing door is operable. Depending on the interest from potential operators, MARITECH will seek required certification from United States Coast Guard (USCG) Marine Safety Office.

EPRIB United States Coast Guard (USCG) Marine Safety Office (MSO) San Diego (California, USA) Safety Bulletin reports 406 EPRIB failures even though self test indicated that they were working. It reports that the failure occurs at the downstream of the test light. If you have one of these units, contact your local MSO for test to find out if the unit is really working before you sail out for the long voyage (or even a short one!) (Sep/1999)

Recently MARITECH assisted a client for obtaining Certificate of Inspection (COI) from USCG's Marine Safety Office. It involved an unusual vessel in the form of an amphibious vehicle typically used by U.S. Army and NATO forces. The vessel owner was denied a COI for not having Engine Exhaust Manifold cooling system . The power plant of this vehicle is gasoline driven unlike diesel engines with built in exhaust manifold cooling system required for higher engine exhaust temperature. There are over 30 of this type of vehicle are currently certified by the USCG under Subchapter T of the 46CFR and operating in the U.S. to carry 20 or more passengers for short duration over the water (protected water). Recent incident (Lake Hamilton, Hot Springs, Arkansas, May 1, 1999) involving a similar vehicle (vessel) probably shook up USCG for operating this type of vehicle on water. However, USCG's own investigation revealed that by faulty repair, a watertight shaft seal was miss-installed which caused water entry into the vessel and it sank like a stone with some loss of 13 lives. USCG's Marine Safety Bulletin stated that vehicles (vessels) of this type have an excellent safety record (1992 - 1998) for operation. (Oct/1999). Maritech's own investigation as regards to design and construction of these type of vehicles for operation as passenger vessels (in the water) indicates otherwise!

MARITECH has developed a design for floating sectional docks in sections of 25 ft long x 8 ft wide with 24-inch freeboard. The structure is made of 5000 series aluminum with truss type construction and with suitably positioned pontoons to provide required freeboard. Each of these 25 ft. sections can be joined end-to-end to make long dock for pier-side service of boats, yachts, and what have you.

MARITECH has developed two catamaran passenger ferry designs based on ABS hull scantling rules for Aluminum construction. The capacities of these two ferries are 200 and 340 passengers respectively. The designs are base the latest IMO resolutions and the Passenger Vessels Safety Act (USA) administered by U.S. Coast Guard for certification.

MARITECH has developed a design for a 28 ft all aluminum landing craft style vessel for operation in inland waters, harbors, and other within protected waters. The vessel may be used as work boat, vehicle transporter, river pollution response and similar work. The vessel is designed for shallow draft operation. Interested builders or buyers are invited to contact Maritech Corp. [USA] (619) 660-0309 for detail.

Recent report of High-Speed ferry operation in certain local body of water in Seattle (USA) area, where local shore-line property owners claimed that the wake-induced waves generated by such a vessel are eroding the shoreline. They sued the ferry operator for slowing down to 10 knots and won through a court order.

Typically, the wake of vessels operating through narrow channels create waves which are then reflected back from the shoreline and encounter the new wake-generated waves by the vessel. The result is Standing Waves. Depending on the profile geometry of the shoreline, depth of the body of water, and the speed of the vessel, these standing waves can have wave amplitudes twice the wake generated waves which would then travel back to the shoreline - and consequential erosion of it.

A research report from UK's MCA (Project No. 420 "Investigation of High Speed Craft (HSC) on routes to land or enclosed estuaries" has some fundamental information about the effect of wake-wash on beach erosion. Maritech has studied the report and summarized the following:

(1) that the wake-wash is a function of depth of water and vessel's speed
(2) that the speed falls into three domains: Subcritical (Fnh <1), Critical (Fnh=1), and Super Critical (Fnh>1)
(3) The length of the vessel is not a factor in the equation

The following chart depicts the general relationship.

Further analysis by Maritech indicates that if the wake-wash is generated below the free-surface, then the wave energy is dissipated fast before the waves reach the shoreline. Monohulls and Catamaran hulls generate free-surface wake which may need special devices to reduce wake-wash. Swath hull technology generate very little free-surface wake-wash because of the inherent hydrodynamic characteristics of SWATH hull technology.

In that respect a SWATH high-speed ferry could be more kind to the shoreline. Experimental verification in a tow tank is required.

What are the possible solutions?

(1) Reduce speed of the vessel
(2) Reduce wave reflection mechanics of the shoreline by changing the beaching angle
(3) Dredge the navigational channel to increase channel depth
(4) Consider alternate hull technology like a SWATH

A combination of all three elements above may be the solution. A recent study by another UK based research group indicates an interesting relationship between vessel's speed and channel depth. Following is an approximate depiction of the result. No additional detail is available.