PTF 9-16
Boat Manual
Hull Specifications

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2.1.1  General Remarks
2.1.2  Hull construction


2.1     Hull Construction
2.1.a. Typical section between two bulkheads



2.1.1. General Remarks 

To attain the highest possible strength with comparatively low weight of hull, the structure, with longitudinal girders, bulkheads, webframes and frames are designed according to the most modern methods of construction, utilizing light materials, laminating processes, plywood constructions and double planking. 

All wood materials are first grade, free from sapwood and suitable for the purpose. Moisture content does not exceed 12 % of oven-dry weight. All plywood are of waterproof marine type. 

All laminations, scarves etc, are glued in accordance with the requirements of "Det Norske Veritas". 

All aluminum parts are of seawater-resistant alloy, treated with primer before other paint is applied. 

All fastenings are of non-corrosive stainless steel in all principal constructional members. Fastenings in conjunction with aluminum are cadmium-plated

2.1.2. Hull Construction (Fig. 2.1.) 

Fig 2.1.a Typical Section Between Two Bulkheads Hull construction (96774 bytes) jpg (41440 bytes) Fig 2.1 Hull Construction

The hull is built of double mahogany planking (1) (inner skin diagonal) on laminated oak keel (2), ash frames (3), oak chines (4) and ash gunwales (5). The deck (6) is laid of water-proof plywood on beams (7) of laminated pine. Bulkheads (8) and webframes (9) are made of water-proof plywood.

The longitudinal strength is obtained with girders (10), (named A.B.C.) deck stringers (11) and sidestringers (12). 

The transom (13) is made of water proofed plywood laid on a frame of laminated ash with vertical stiffeners of pine (14). Webframes (IS) at frame 53, 55 and 60, and brackets (16) at frame 58 and 60,are made of seawater-resistant aluminum. 

The stem is protected with a 3 mm. stainless steel shear- water, shaped to fit the stem from stemhead to frame 16. 

The corners of the transom and the oft part of the chines are protected by 3 mm thick stainless steel angle bars.

 The hull is fitted with necessary doubling for stern-tubes (17), under-water exhaust (18), propeller brackets (19) and rudder stock (20). In the bottom of the after peak there are laid two bottom frames (21), at frame 67 1/2 and 68 1/2, as a reinforcement for the brackets. 

The two gun foundations are built as integral members of the hull structure and distribute stresses to the bulk- head, webframes and main longitudinal girders. 

The foundations (22) are mode of oak with reinforcement of seawater resistant aluminum. The foundation (23) is made of mild steel with stanchions of seawater resistant aluminum. Bottom frames (21) are mounted at frame 48 1/2, 49 1/2, 521/2 and 53 1/2 to obtain the stress from the gun foundation. 

The main engine beds are of light alloy castings mounted on "A," and "B,"  girders, which are strengthened by aluminum plating on each side between bulkheads at frame 49 and 64. Vee-drive gears are mounted on light alloy chainplates fastened to girders "A," and "B." 

The installation hatch (24) on the aft deck is constructed of aluminum with coamings and flanges of water-tight mounting. 

The bridge is built up of waterproof plywood. The front side (25) is especially reinforced with laminated pine stiffening ribs covered with plywood.