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One Design · Keelboat

Sonar parts, rigging and specifications

The Sonar is a keelboat one-design class designed by Bruce Kirby (1979), with a published length overall of 23 ft (7.01 m). MAURIPRO lists 79 parts for the Sonar below, grouped by system, with live prices and stock.

  • Keelboat
  • 79 parts
  • 14 published figures

Your Sonar at MAURIPRO

What you can do on this page.

01Shop parts by system79 parts for the Sonar, matched by part number and grouped by system.Shop all parts →
02Check the specifications14 published figures, each with its source.See specifications →
03Halyards & sheets made for it24 lines made up to this boat's lengths.Shop halyards & sheets →
04Get expert helpNot sure a part fits your Sonar? Send us your sail number and year.Contact us →

Shop Sonar by system

Sonar parts

Prices and stock are live from our catalogue.

Harken part numbers cross-checked against Harken's published one-design deck layout for the Sonar (checked 2026-11-04).

Parts marked "Sized for this boat" are chosen from the manufacturer sizing guides published on our Selection Guides pages (Harken winch chart, Forespar pole guide, Harken mainsheet guide, Schaefer hardware chart) using the published dimensions of the Sonar. They are not specified by the class rules; check your class rules for limits before racing.

Rope sold by the foot is added at the cut length shown on the card.

Sonar specifications

SpecificationPublished figureSource
Length overall (LOA)23 ft (7.0 m)Sonar Class Association - Specs page (sonar.org/boat/specs, undated)
Waterline length (LWL)19 ft 11 in (6.1 m)Sonar Class Association - Specs page (sonar.org/boat/specs, undated)
Beam7 ft 10 in (2.4 m)Sonar Class Association - Specs page (sonar.org/boat/specs, undated)
Draft3 ft 11 in (1.2 m)Sonar Class Association - Specs page (sonar.org/boat/specs, undated)
Hull weightClass minimum complete hull and rig as raced, dryThe dry weight of the complete hull and rig as raced including the following, shall not be less than 950 kg (2,090 lb)Sonar Class Association - Class Rules v1.13, rule C.4.1 Weight, effective June 10, 2015
Displacement2100lb – 950kgSonar Class Association - Specs page (sonar.org/boat/specs, undated); matches Wikipedia, MAURIPRO Sailboat Data
Ballast900lb – 408kgSonar Class Association - Specs page (sonar.org/boat/specs, undated); matches Harken one-design deck layout page
Upwind sail area250 sq.ft – 23.2 sq.mSonar Class Association - Specs page (sonar.org/boat/specs, undated)
Spinnaker / gennaker area245 sq.ft – 22.8 sq.mSonar Class Association - Specs page (sonar.org/boat/specs, undated)
Mast lengthClass min/max spar lengthMast Length: minimum 10275 mm, maximum 10315 mmSonar Class Association - Class Rules v1.13, Section F Mast dimensions, effective June 10, 2015
CrewDuring a regatta the crew shall consist of a minimum of three persons and the number shall not change.Sonar Class Association - Class Rules v1.13, rule C.2.1(a), effective June 10, 2015
DesignerBruce KirbySonar Class Association - Class Rules v1.13, title page, effective June 10, 2015
BuilderNew International Sonars are built to order by Rondar Raceboats in their factory in Wiltshire, England.Sonar Class Association - home page (sonar.org)
First built / designedDesign yearDesigned in 1979Sonar Class Association - Class Rules v1.13, title page, effective June 10, 2015

Figures are shown as each source publishes them, with the other unit converted. Class rules set the measurements that count for racing.

More for the Sonar

Sonar tuning guides

  • North Sails: Sonar Tuning Guide5 pages
  • Dave Perry: Sonar boat handling and speed thoughtsVersion 2023 · 6 pages

Tuning guides belong to the sailmakers that publish them. MAURIPRO does not host or reproduce them; ask the sailmaker or your class association for a copy.

Sonar class rules and references

  • Class rules: Class Rules v1.13, effective June 10, 2015
  • Class association: sonar.org
  • Builder: rondarboats.com

References checked 2026-11-04.

Sonar buying questions

What Sonar parts does MAURIPRO carry?

79 products are listed for the Sonar on this page: halyards, sheets & control lines (35); blocks & sheaves (14); cleats, clutches & fairleads (4); travelers, tracks & cars (5); winches & handles (1); spinnaker poles (1); and more. Prices and availability shown are live from our catalogue.

How do I know a part fits my Sonar?

Each part here is linked to the Sonar because its exact manufacturer part number appears on the Sonar parts lists we reviewed (including Harken's published one-design deck layout for this class). Fit can still depend on your boat's year, builder and rig, so check the product details and your class rules, or ask our technical team before you order.

Where can I find the Sonar rig dimensions?

Our Sonar Sailboat Data page lists the rig dimensions (I, J, P, E) and other published data we hold for this boat. Figures there come from a sailboat database and may differ from class measurement rules.

Can I order halyards and sheets made for the Sonar?

Yes. Our Sonar - Halyards & Sheets page lists 24 halyard and sheet options made up for this boat.

Are there tuning guides for the Sonar?

Sailmakers have published tuning guides for this class, including North Sails (Sonar Tuning Guide, Undated web guide (current page)); Dave Perry (Sonar boat handling and speed thoughts, June 2023). These guides belong to their publishers; MAURIPRO does not host or reproduce them, so please get them from the sailmaker or your class association.

Which rules govern the Sonar?

The class is governed by its class rules (Class Rules v1.13, effective June 10, 2015). Check the current edition with the class association before buying parts for racing.

Not sure which part fits your Sonar?Send us your sail number, year and builder and our team will check it.
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