installation notes

Daggerboard Plans

Let your cat perform

replace the original boards with a single large daggerboard.

If you are building a boat and haven’t started yet, or you’re early in the build, now is a good time to design and build in a single board solution. If you have already built boards, it will still be easier to make changes now than when you are in the water.

If you own a cat and you’re not happy with the windward performance, maybe it is time to make a change. It is a big job, but worthwhile. I spent 3 months designing and building my board and case, then slipping the boat and installing it. It was a lot of work, but it was the best thing I did for my boat. I thanked myself everyday I sailed after that.

These boards glide on nylon bearings. They can be raised and lowered under full sail with little effort. I engineered the board and case to handle large loads with small clearances. The board is quiet and doesn’t thump at anchor or underway.

Where to install?

Ideally, install the board in a section of the hull where you can stand up behind the main mast bulkhead. If you have the room, position the board and case off-centre in the hull, so you can walk through. How far off-centre depends on the hull’s width, shape and draft. The plans include drawings of the Tokyo Express install with details on fibreglass layup, fillet sizes and case to hull connection details, to use as guidance for you plan your installation.

If you are not using CNC to cut the wood full-size, 1:1 full-scale plots in A4 and A3 format are included in the plans. Print and use them to trace the shape of the ribs onto the plywood. This saves considerable time by not having to measure and draw the intricate shapes of the ribs from the template drawings.

large daggerboard vs small
daggerboard plans

What’s in the plans

The plans include 15 PDF documents with over 100 pages of elevation drawings, templates, layouts drawings, 3D CAD images, notes and tips to help you build your board.

Plans include:

– Elevation drawings
– Detailed template drawings for all parts
– Build notes with tips on what I learned, building my board
– Photos and example drawings from my installation
– Material lists and estimations of amounts needed
– CNC files for all parts, including layout drawings
– A4 full scale 1:1 overlapping plots for cutting manually.

A quicker way to trace the ribs onto wood than measuring from templates.

Daggerboard Plans – TE40

(suit 40ft cats)

This board suits 40ft (12m) cats plus or minus 5ft.

Install the case in either port or starboard hull, off-centre, usually to the inboard side. The usual fore-and-aft position is with the leading edge of the board roughly inline with the mast. Mount the case with the forward edge up against the mast bulkhead. Adjust position as necessary.

Main dimensions of board:

– Profile – NACA 63-012
– Chord – 1225 mm (48 in)
– Height of board = 5m (16.4 ft)
– Draught (max) = 2.8m (9 ft)
– Draught (retracted) = 700 mm (2.3 ft)
– Board area (in water) = 2.7 sq-m (29 sq-ft)
– Maximum Case length (fore and aft) = 1274 mm (50 in)
– Max Case width = 195 mm (7.7 in)
– Case height = to suit your hull

Daggerboard Plans – TE30

(suit 30ft cats)

The TE-30 board suits 30ft (9m) cats plus or minus 5ft.

As for the TE-40 board, install the case in either port or starboard hull, off-centre, usually to the inboard side. The usual fore-and-aft position is with the leading edge of the board roughly inline with the mast. Mount the case with the forward edge up against the mast bulkhead. Adjust position as necessary.

Main dimensions of board

– Profile – NACA 63-012
– Chord = 1050 mm (48 in)
– Height of board = 4.3m (14.1 ft)
– Draught (max) = 2.4m (8 ft)
– Draught (retracted) = 500 mm (1.6 ft) (depends on hull & lifting system)
– Maximum Case length (fore and aft) = 1096 mm (43 in)
– Max Case width = 167 mm (6 in)
– Case height = to suit your hull

 

single daggerboard

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