NU Flotilla Company SWATH Hull Barge Construction

SWATH Hull Barge Construction

We have developed a barge construction system that incorporates a factory built FRP or fiber reinforced polymer, bridge truss element. Our construction plan incorporates these into our barge design. The strength of these bridge truss elements when compared to steel is very close. The difference is in the weight and the cost. While a bit higher in price when compared to a galvanized steel frame truss they will never rust or corrode so they will provide a longer service life to the barge. The image below demonstrates the structure of the barge.

These FRP bridge truss elements are fabricated primarily from high-strength E-glass and isophthalic fire retardant polyester resin (Series 1525).

Weathering and ultraviolet light protection is provided by addition of a veil to the laminate construction.

Minimum material strengths and properties are as follows:
Tension 33,000 psi
Compression 33,000 psi
Shear 4,500 psi
Bending 33,000 psi
Young’s Modulus 2,800,000 psi

The minimum thickness of the FRP composite elements are as follows unless otherwise specified: Square tube members (closed type shape) shall be 0.25 in. Wide-flange beams, channel sections, and angles (open type shapes) shall be a minimum thickness of 0.25 in. Standard plate shall be a minimum thickness of 0.25 in.

They are constructed using 316 Stainless Steel bolts and nuts for a long lasting rust resistant construction.

Since we will be building the frame completely out of FRP we plan to use the same materials for the hull of the barge as shown in the image below.

The composite outer shell cladding system is made from high quality pultrusion sheet pile material. This material is 16 to 18 inches in width and is interlocking to form a continuous shell structure and uses external cross bracing to provide added strength to the structure. This same material is commonly used to hold back tons of fill along a shoreline. In its most common use this material is used to hold in tons of fill rock, and dirt on one side, and a body of water on the other. The strength of this material is 30,000 PSI in compressive strength, flexural strength, and tensile strength. This is far in excess of any other material of this weight and cost.

The sheet pile we have designed our barge construction around is produced in the USA from materials made in the USA. As such they qualify for export bank financing.
The weight, strength, and cost are comparable. We then finish this material with a final UV stable urethane coating to improve on the rather dark and utilitarian appearance of the sheet pile material.
The deck will is made from a similar pultrusion material that is designed to fit tongue and grove together to form a strong deck platform to construct upon.
The barge is then completely filled with 2 lb. urethane foam so moisture does not reach the inner structure. The inner surface of the sheet pile is also coated with a heavy urethane coating to prevent water from seeping into the structure from the bolt holes. Quality engineering, and construction, and advanced materials ensure the owner of these barges with many decades of trouble free ownership.