Copyright 2011 CONRAD YACHTS All Rights Reserved
Tuna 20FCC - #06
Full Cabin Compact
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Assembly Drawings:                          
( for
detailed construction study only )
Digital Package:                                             
  1. Assembly drawings.
  2. Parts list.
  3. Nest.
  4. The use of the cutting files-CNC cutting.     
please enquire
Building kit:                                                         
* Does not include tubing, cleats etc.
please enquire
Other Features.
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Hull Characteristics.
The hull can be best described as a modified constant deadrise form, the most 2.
Relatively high deadrise at transom(18 degrees), makes her much more comfortable in
sea way than the majority of boats this size, whose deadrise is generally in the 13 to 16
degrees range.
3. The innovative, variable width chine flats are wide aft, gradually narrowing from
amidships forward. The wide chine flats aft give the hull extra lateral stability, while
narrow chine flats forward, allowing the hull to move through the water,  prevent
slamming against oncoming chop.
4.Using the engine bracket, instead of mounting the engine(s) on the transom, allows
the engine(s) to sit a bit higher and further aft of the end of the hull. This improves the
"hole shot" and allows the propeller to work in less turbulent water flow.
5.  The Tuna 20 FCC cabin has a full standing headroom, which is rare on an 18'
boat. Thanks to the wide hull, the boat is very stable. Perfect commuter
  • Hull length
18 feet
  • LOA
20 feet
  • Beam
8 feet
  • Draft - hull only
13 inches
  • Draft - engine leg down
29 inches
  • Deadrise at transom
18 degrees
  • Transom bracket angle
13 degrees
  • Minimum cockpit depth - no rail
25 inches
  • Fuel capacity
60 USG
  • Power - single or twin
50-150 hp
  • Capacity ( people)
  • Approx. aluminum weight
1,500 lb
  • Design displacement
3,000 lb
1. All  major hull structure components are designed and calculated to conform to the requirements of ABS
(American Bureau of Shipping).
2. The maximum beam is 8’-0". This is relatively wide for a 20' boat. Tuna 20 is a stable fishing or working platform.
3. Whenever possible, welds are avoided: entire cockpit sole(from the bow to the engine bracket) is made of only two
lengthwise halves, welded together, then welded to topsides(side plates) around the perimeter, and slot welded to
structural members underneath. Each hull half is one piece, so are side plates. This approach yields a much fairer hull.
4. The hull is framed longitudinally, which, again, produces a fairer hull, eliminating the "hungry horse" look of many
metal boats.
5. The structure consists of longitudinal girders and transverse frames, which “egg crate” into one another to make
assembly quick and accurate.
6. I believe in being able to access and remove the fuel tank, if necessary, even after the boat is completed. This is
accomplished by locating the fuel tank under a “soft patch” in the cockpit sole.
7. Alloys used are all top marine grade 5000 series.
Bottom - 1/4"   - 5086 H116, or 3/16"
Sides    - 3/16" - 5086 H116, or 3/16"
Cabin    - 1/8"  - 5052 H32