This model is based on a detailed Elco drawing for all 80' boats. Quantity used per boat is 2, 3, or 5. The base mounting flange on these bronze bitts is thickened slightly, and screw detail removed, to meet printing minimums. Mounting pins are 1/8" diameter and 0.17" length less whatever the saw takes after cutting them off. Or if you trimmed the sprue off vertically at the pin sides they would be 0.25". They also have a shallow groove around the circumference to help them hold better.
Deck plates of 1/8" thickness were used under the bulkhead 4 forward bitt and the PT 731-760 refueling at sea bitts amidships at bulkhead 21. A template for these is available here:
http://www.pt103.com/images/3D_parts/3DP_Elco_80_Mooring_Bitt_Deck_Plates.jpg
Installation
Drill holes according to the location guide below. Clean parts well. For best results roughen up mounting surfaces and use epoxy. J-B Weld (not J-B Kwik) is a favorite of mine, it has a slow cure (working time 45 minutes) and a medium viscosity. After mixing, you can let it stand for 15 minutes or so and it will thicken up some to help it stay in place. Make sure to fill the pin grooves with adhesive, and inside the center lightening hole of the bitt. This hole has a small lip around the opening to help adhesive hold better.
Quantities and Locations, to center of bitts
Measurements are given in full scale and are taken from Elco drawings.
PT 103-108:
Quantity: 2. PT 103-108 used a towing bitt instead of a mooring bitt at bulkhead 4.
Locations, best guess from photos is at same position as PT 731-760 aftermost bitts:
2 centered on frame 69, 946 1/4" aft of forward point (about 19.9" forward of aftermost edge of boat), 6 3/4" inboard of guard (outermost edge of boat) port and starboard. Horns to be parallel to boat side.
PT 109-196, 314-367, 372-383, 486-545, 546-563:
Quantity: 3 or 5. PT 522-545 had refueling at sea bitts (drawing not available) like PT 731-760 so they used quantity 5.
Locations:
1 centered on bulkhead 4, 76 1/4" aft of forward point on boat center line. Horns to be at right angles to boat center line.
2 (PT 522-545 only), best guess from photos is centered on frame 26, 370 1/2" aft of forward point, about 9" inboard of guard (outermost edge of boat) port and starboard. Horns to be parallel to boat side.
2 centered on bulkhead 61, 853 1/4" aft of forward point, 50" outboard of boat center line port and starboard (slightly outboard of outboard face of coaming). Horns to be parallel to boat center line.
PT 565-624:
Quantity: 5.
Locations unknown (drawing not available), best guess from images:
1 centered on bulkhead 4, 76 1/4" aft of forward point on boat center line. Horns to be at right angles to boat center line.
2 centered on frame 26, 370 1/2" aft of forward point, about 9" inboard of guard (outermost edge of boat) port and starboard. Horns to be parallel to boat side.
2 centered on frame 69, 946 1/4" aft of forward point (about 19.9" forward of aftermost edge of boat), 6 3/4" inboard of guard (outermost edge of boat) port and starboard. Horns to be parallel to boat side.
PT 731-760:
Quantity: 5.
Locations:
1 centered on bulkhead 4, 76 1/4" aft of forward point on boat center line. Horns to be at right angles to boat center line.
2 centered on bulkhead 21, 310 1/4" aft of forward point, 6 1/2" inboard of guard (outermost edge of boat) port and starboard. Horns to be parallel to boat side.
2 centered on frame 69, 946 1/4" aft of forward point (about 19.9" forward of aftermost edge of boat), 6 3/4" inboard of guard (outermost edge of boat) port and starboard. Horns to be parallel to boat side.