Sailing yachts

Harrison Butler Z4 Sloop

(REF: 29722)


  • Designer: Dr T. Harrison Butler
  • Builder: Alfred Lockhart Marine of Brentford
  • Year: 1939
  • Location: W. Sussex
  • Length on deck: 21'
  • Beam: 7'2"
  • Draft: 4'6"

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Full specification

Wooden Ships Comments on this Harrison Butler Z4 Sloop

Harrison Butler Z4 Tonner with raised topsides.

Built by Alfred Lockhart Marine of Brentford in 1939.  One of the 50 or so Boats built to the Zyklon design by Dr T. Harrison Butler between 1938 and 1939.

Approximately 6 were built to this slightly altered design with raised topsides to increase the volume of the cabin.

Harrison Butler Association Certificate of Authentication No.1

HB Association Sail No. HBZ435.

This boat has been in the present ownership since 1981 and used extensively for family cruising, with young children growing up aboard the boat cruising around the UK.

Thorough survey from November 2023 with a detailed list of invoices showing work done since that survey.  Copy of this survey and invoices available on request.


Length on Deck            21’

Beam                               7’2”

Draft                                4’6”

Thames Tonnage


  • Carvel planked in pine, all copper rivet fastened to steam bent oak timbers.
  • Cast iron ballast keel with ferrous keel bolts.  All new in 2005 with samples drawn in 2018 and 2021, found to be sound.
  • Galvanised steel strap floors across the centreline.  It is understood the throat bolts and floor bolts were replaced in 2005.
  • Varnished mahogany sheer strake plank makes up the raised topsides.
  • Straight laid T&G pine deck, overlaid with plywood and sheathed in glass cloth.  New deck covering laid in 2007.
  • Varnished teak forehatch new in 2017.
  • Typical Z4 cockpit which is deep and safe.  Varnished mahogany thwarts either side and aft.  Painted wooden sole boards lift to access the aft bilge.


  • Fractional Bermudan sloop rig on a deck stepped varnished spruce mast.  Mast new in 2008.
  • Varnished wooden slab reefing boom.
  • Mast is stepped in a galvanised tabernacle with compression posts to the galvanised ring frame below.
  • Stainless steel standing rigging replaced   piece at a time when required.  External galvanised chain plates.
  • Mainsail and jib in serviceable condition.


  • Beta Marine 13hp twin cylinder diesel fitted new in 2002.
  • Unlike most Z4 yachts she has a centreline propeller.  Single lever controls to a fixed 3 blade propeller.
  • Recently fitted deep Sea Seal stern gland.  Engine seacock new in 2021.
  • Stainless steel fuel tank under the aft deck.
  • 12 volt 100ah battery new in 2020, charged from the engine alternator.
  • Auto electric bilge pump.
  • Whale Gusher manual bilge pump.


  • 4 berths including 2 saloon settee berths and 2 pipe cot berths above.
  • Approximately 5’ headroom in the saloon.
  • Step down from the cockpit with original joinery port and starboard.  To port is a storage locker and to starboard is a work space area that can be used as a galley.  Primus paraffin stove included.
  • A long settee berth either side with ample sitting headroom.  Storage space beneath the berths.
  • Above each settee is a pipe cot berth that pulls out when required.
  • Centreline passage into the forepeak where there is a Simpson Lawrence manual sea toilet under the joinery which discharges directly overboard.  Storage lockers around the forepeak with chain locker below.


  • Steering compass
  • Garmin 451map GPS chart plotter
  • Seafarer 5 echo sounder
  • Walker trailing log
  • Hand bearing compass
  • Barometer
  • Clock
  • Standard Horizon HX210 waterproof handheld VHF radio


  • 25lb CQR anchor with 34m x 6mm chain (2018)
  • 15lb CQR anchor
  • Manual anchor windlass mounted on the mast
  • Mooring warps
  • Fenders


  • Bunk and berth cushions
  • Simpson Lawrence sea toilet
  • 2 x gimballed cabin paraffin lamps


  • Auto electric bilge pump.
  • Whale Gusher manual bilge pump.
  • 12 volt 100ah battery
  • Shore power cable
  • Radar reflector
  • Horse shoe life buoy with throwing line


  • Pair of bronze non-self tailing original cockpit sheet winches

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These particulars have been prepared in good faith from information provided by the Vendors and are intended as a guide, Wooden Ships cannot guarantee or warrant the accuracy of this information nor warrant the condition of the vessel. The Purchaser should instruct his agent or surveyor to validate all details as necessary and satisfy himself with the condition of the vessel and its equipment.