Core Sound 20 Mark 3


CS-20 Mk3 Specs:
LOA………20′-0″ [6.1] m
BEAM………6′-4” [2.16] m (Trailer-able width)
DRAFT………9" - 3'-614" [0.23 -1.07]m @ DWL
SAIL Area………180 sq. ft.
WEIGHT………600-650 lbs [272-295]kg
*DISPLACEMENT………1500 lbs (773 kg) @ DWL

*@DWL With people water ballast and gear

Click here to view our Video and builder spotlight gallery for the Core Sound 20 Mark 3

Based on the popular and race proven Core Sound 20, the new "Mark 3" is fully capable coastal cruiser with water ballast that make her self righting from a capsize. Why is this the "Mark 3?" here is a history of the evolution of the Mark 3 series of Core Sound designs. If you're interested in all the same features in a slightly smaller package, check out the Core Sound 17 Mark 3. More pictures click here. Standard features of the CS-20 Mk3 include:

  • Kick up rudder and weighted centerboard.
  • A raised deck cabin with spacious bunk and storage space below.
  • Porta potti storage in cabin.
  • Water ballast and a self draining cockpit.
  • Main tabernacle for faster rigging and.
  • Optional mizzen tabernacle.
  • Reefing from the cockpit.

Keep reading for information on all the available options and prices for the Core Sound 20 Mark 3!

Level 1 CNC Plywood Kit: $3,750
Th level 1 kit parts include every plywood part we can cut on the CNC machine. All parts are made of the highest quality BS 1088 okume marine plywood. This option is great for those builders who are looking get a real head start on the build and perhaps already have a stock of solid wood and are fairly confident in their woodworking skills. 

Included in the Level 1 kit is a full size mylar template providing an easy way to produce the solid wood parts not included in the basic kit. Outlines for the tiller, tabernacle parts, rudder, centerboard and rudder shaping detail are shown in this template to name a few. 

The basic kit also includes the three cradle parts and plywood corner gussets shown below on the building cradle. These are attached to a shop made frame of 2×6 rails and 2×4 legs all detailed in the plans. Below, a CS-20 Mk3 sits nicely on her cradle.

Full Size Templates and Construction Plans ONLY: $220

The plans set consists of full color 11 x 17 sheets that detail all aspects of construction and assembly. Kit parts are labeled in each drawing referencing the kit parts throughout. The deck framing and Main Rigging sheet are available to view as a sample by clicking in the list below. We have taken all of the parts from the CNC kit and nested them in two 21 foot x24 inch strips of dimensionally stable Mylar sheet that make up the full size templates. In use, the sheets are taped together aligning the strike up marks to produce a templates sheet that can be used to transfer all of the part outlines onto plywood for cutting with a jigsaw. Recommended methods and sheet count are shown in the included detail sheet that accompanies the templates.
Note: The plan sheets are designed to accompany the full size templates or the CNC cut Kit. There is no lines plan because the templates are full size. There is no lofting required. This option is mostly for overseas builders.   

-Parts list
-Cradle assembly
-Main Assembly
Deck Framing
-Deck Plan
-Bulkhead Detail
-Tabernacle Detail
-Cabin Hatch Assembly
-Cabin Hatch Detail
-Cockpit Hatch
-Rudder Detail
-Centerboard Construction
-Centerboard Rigging
-Spar Detail
-Sail Plan
Main Rigging
-Mizzen Rigging
-Optional Reefing Detail
Image Image

What else will I need?
Solid wood for stringers and cleats is not included. We prefer our builders to locally source this material and rip into long lengths for stringers, inwales, and gunwales. . It is not practical for us to ship these long pieces. If you are picking up your kit from our shop we can rip these pieces for you and include them in the kit. Just let us know ahead of time so we can put together these extra parts.

Other items to be purchased separately: All available from B&B.
-Mast kit
-Hardware kit
-Lines pack

The basic kit comes with solid cabin top panels which can be fitted out however the builder desires. Some builders have expressed interest in a long "trench" style of companionway allowing for walking forward in the cabin. A trench opening however creates a unique design problem of how to seal the hatch for heavy weather sailing and also make it easy to open and easy to secure the boat while away. In the end, our stock companionway kit was developed after thinking long and hard about the boat's potential and what we felt the majority of builders would want.

We settled on a drop board style companionway opening with a sliding hatch for accessing the cabin. Forward, an 18 1/2" x 22" hinged hatch provides a secure location to deploy an anchor, hank on the mainsail and tie up reef points. This hatch layout also allows for the future installation of a soft dodger over the sliding hatch "garage" as well as a solar panel over the hinged forward hatch.

CS-20 Mark 3 Build Logs:

Have a build log you’d like to share, send us a link.

The first 20 Mark 3 built by Doug Cameron. Build log for Hull #1. Don’t forget to check out Doug’s blog.

Jay and Carol’s build log of their CS-20 Mk3 #2. Installation of a water pump used in ski boats as her ballast pump allows water to be added or removed with the push of a button.

Here is Steve’s build log of his CS-20 Mk3 #3.

Here is Peter Mcray’s build log of his CS-20 Mk3 #5. Peter asked us to preassemble the hull at our shop which we did and he picked her up on a trailer and took home the rest of the kit. His build is going well.