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This article discusses important vessel design considerations for small boat harbors and ports, including vessel size, draft, displacement, and more. It also explores the site constraints and characteristics of ports and small boat harbors.
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Vessel Design Considerations • Vessel Length: • Placement of Breasting Dolphins (Fenders) • Placement of Mooring Dolphins • Size of Turning Basin • Vessel Beam: • Width of Access Channel • Width of Mooring Basin
Vessel Design Considerations • Vessel Draft (Loaded): • Determines Required Water Depth • Determines Current Loading • Vessel Freeboard (Empty) • Determines Wind Loading • Vessel Displacement (weight) • Determines dock structure • Determines fender Design (Energy)
Site Considerations – Constraints: • Upland Ownership • Upland Access • Upland Area • Use of Adjacent Lands • Deep Water • Shallow Water (Dredging?) • Water Area (Turning Basins) • Wave Exposure (Swell) • Wind Direction • Ice • Environmentally Sensitive Areas
Port – definition • A Location for Transfer of Cargo Between Ships and Shore. • A Port Normally Includes Infrastructure of Docks and Uplands Necessary for Commercial Activity. • Cargo vessels generally range from about 150 feet to over 900 feet
Port Characteristics • Cargo vessels generally range from about 150 feet to over 900 feet. • Dock structures are generally fixed (not floating) and vessels are attended at all times. • Note: Areas of high tidal ranges require constant attention to mooring lines.
Small Boat Harbors • A location for permanent or temporary moorage of small unattended vessels. • Moorings normally consist of floating docks. • The vessel size in harbors generally vary from about 18 foot skiffs up to about 150 foot commercial fishing boats. • Larger boats are more often associated with ports and movement of cargo.
WHARF • Moorage parallel to shore. docking on only one side • Good for heavy duty transfer of cargo – (e.g. containers) • Normally constructed close to shore where depths increase rapidly
PIERS • Good for Access to Deep Water • Vessels Can Be Moored on Two or More Sides • Have a Limited Capacity • Have Limited Working Space • Commonly Used for Fuel Transfer
Types of Docks • Wharf • Pier:
Most Inland Waters about 4 to 6 second design wave Distribution of Ocean Wave Energy Residual Ocean Swell – about 10 to 15 seconds 84 SPM
Linear Wave Theory L=5.12 T^2 Fig. 2-6 84 SPM
Requires Iterative Solution Common Equations for Port and Harbor Design Wave Length (Deep Water): When depth(d) > L/2 Deep or Lo= 5.12 T 2 (feet) Wave Length : When depth(d) < L/2 However: Shallow
Fender Design For high tidal range fenders may be designed to move upand down with the tide. For low tidal range fenders can be at a fixed elevation.
ENVIRONMENTALDock design & Fish migration Pile supported docks are normally preferred for fish migration; however there may be concern for shading There is concern that vertical faced docks force juvenile salmon into deep water. Sometimes this can be mitigated by hanging material from dock face.
ENVIRONMENTALDock design & Fish migration Breach beach beach