Home About Sailomat Technical Info Questions Comments Back to Sailomat 700

Self-Steering Principle

SAILOMAT self-steering systems use the all-mechanical 'servo-pendulum' principle. This is the most advanced and most reliable principle known, offering a desirable combination of high sensitivity, high steering torque and high yaw damping. The self-steering is fast, automatic and efficient.

Basically, a 'servo-pendulum' system consists of a dual-axis air-vane sensor for course deviation, a servo blade ('oar blade') suspended from a pendulum carriage into the waterflow for signal amplification, and torque output lines from the pendulum carriage to the tiller or the wheel of the yacht. The figure shows a simple 'servo-pendulum' SAILOMAT 536 (predecessor to model 601) system operating a tiller-steered yacht.

The course is selected by turning and then locking the vane base (turret) on the mast tube around its vertical axis. When the yacht is sailing on the desired course, the air flow is parallel to the flat surface of the air vane, which is well balanced (with the counterweight) around the near-horizontal pivot axis. The vane is in it's neutral, vertical position.

Self-steering action is described in the following steps (1) to (5):

1. With the yacht slightly off course, the air vane is pivoted by side air flow ( small angle of attack). A mechanical torque is generated. This is the course deviation signal.

2. The vane torque (signal) is mechanically transferred to axial pushrod motion inside the circular mast tube of the SAILOMAT.

3. The pushrod motion is converted into a slight turning motion of the servo blade.

4. With the turned servo blade the water flow generates hydrodynamic side force , driving the servo blade and the servo-pendulum assembly to the side (swing motion), away from the neutral position. The servo blade thus extracts mechanical energy from the water flow. The pendulum pulls the line circuit with a high (amplified) force, typically 100-1000 times higher than the 'signal' force on the air vane sensor.

5. The line circuit controls the helm (tiller or wheel) with pull/pull lines, and the yacht's main rudder steers the yacht back to the desired heading. Air vane , servo-blade and main rudder then return to original their (neutral) positions. The self-steering course correction is then completed. Properly designed, the steering correction should be fast, highly accurate and also damped to avoid course oscillations.

Back to Self-Steering Principle


Technical Data

"TYPE
- State-of-the-art 'servo-pendulum' (patents).
- Dual-axis wind vane sensor.
- Line coupling to yacht's main rudder.
- 170 / 140 deg pendulum swing.
- Universal base, instant removal of system.

LINE CIRCUIT
- Pull/pull line circuit to tiller or wheel.
- Many circuit options, consult manual.

DIMENSIONS
- Request dimensions or scale drawing
from SAILOMAT Design Office.
- SAILOMAT 601-S series: short shaft
- SAILOMAT 601-X series: long shaft

SERVO BLADE
- SAILOMAT 601-S series blade lengths: B= 800, 920, 1020, 1220 mm
- SAILOMAT 601-X series blade lengths: B= 920, 1070, 1220, 1350 mm

MATERIALS
- Light alloy (marine grade) castings,
- aluminum extrusions, (high yield strength 28 kp/mm2, 40,000 psi),
- advanced composite bearings,
- 316 ss fasteners, Helicoil thread inserts.

PENDULUM
- Swing ability 140/170 deg, out of water
= overload safety.
- 'Parking' in upright position ( 170 deg).

BASE
- 170 x 305 mm (6.7"x 12.0") compact 'footprint'.

WEIGHTS
- SAILOMAT 601-S series: from 20.5 kg (46 lbs)
- SAILOMAT 601-X series: from 23 kg (51 lbs)

MAIN SHAFT
- Very high strength, OD/ID: 60/48 mm (2.36"/1.89")
- Wall 6 mm

OFF-CENTER MOUNTING
- Permitted. (Select slightly longer blade).

WHEEL COUPLING
- Use optional wheel coupling for wheel-steered yacht.

ATTACHMENT
- Simple. Universal Base UNB. (Zero torque on base).
- Only 4 bolts. High mounting - near deck level.

TRANSOM ANGLES
- Universal Base UNB can be directly mounted to a wide range of transom angles. Also canoe sterns.

REMOVAL
- Instant removal of system from UNB.

VARIABLE RATIO
- Yes, 6 positions (vane-to-oar), for enhanced downwind sensitivity & performance.

COURSE CONTROL
- Standard: rotate (turret) vane base casting on mast tube. Control handle/locking device.

REMOTE CONTROL
- Optional, mechanical (RCC)

VARIABLE RATIO
- Yes, 6 positions (vane-to-oar), for enhanced downwind sensitivity & performance.

ELECTRIC INSULATION
- Servo blade, shafts and pendulum components are electrically insulated, minimizing galvanic corrosion.

OVERLOAD PROTECTION
- Built-in, by non-restricted pendulum swing (out of water).

IMPACT PROTECTION
- Yes, Shear pin in blade holding fork.

EMERGENCY STEERING
- Possible. System can be used for emergency steering with disabled main rudder. For increased rudder area select optional component. 'BEST'.

Back to Technical Data


Main Features

If your boat's rudder is lost or disabled, the standard SAILOMAT 601 self-steering system can be converted into an emergency steering device, that can hold a desired course and assist in bringing your boat home safely. Normal self-steering would have to be exchanged for manual emergency steering.

The option of using SAILOMAT 601 for emergency steering is made possible primarily by the high strength of the SAILOMAT shaft, holding fork and servo blade components.

In principle, the regular SAILOMAT 601 can be used directly for manual emergency steering, although in most situations, steering with a standard servo blade (and locking the pendulum motion with lines positioned at the fork or lower, and running around the transom) would be somewhat inefficient due to the small blade area.

Instead, for more efficient emergency steering with SAILOMAT 601 we recommend a conversion with the following steps:

a) Increasing the oar blade surface using the optional SAILOMAT component 'BEST' (Blade Extension for Emergency Steering),

b) dismantling the pedestal/ rocker arm and mast tube components, and

c) hooking up pendulum 'locking lines' and manual steering lines to the special tiller on 'BEST'.

With 'BEST' the SAILOMAT 601 servo blade surface is more than doubled to approximately 0.23 sq. meter ( 2.45 sq. feet), and then considerably better for emergency steering of a sailboat than the standard oar blade. With the 'BEST' steering blade size still significantly smaller than the yacht's normal rudder, steering ability limitations exist. The emergency steering system should be considered as an assist device, capable holding the boat on a steady course, but with limited maneuvering ability and slower course corrections.

'BEST' specifications:
(Blade Extension for Emergency Steering)

Rudder area +0.228 sq. meter (+2.45 sq. feet)
Area increase +106%
Length 800 mm (31,5 in.)
Chord 285 mm (11,2 in)
Dept. adjustable
Steering by special tiller and control lines
Material aluminum 6061 T6

The two pendulum locking lines are secured around the top section of the 'BEST' rudder, then wrapped around the yacht transom, and secured to the deck. In this way the rudder blade is directly supported by the locking lines, and the mechanical loads on the other SAILOMAT components minimized. The steering lines are attached to the aft facing special tiller from the trailing edge of the 'BEST' blade.

For further details of converting the regular SAILOMAT 601 system with 'BEST' into an emergency steering please contact Sailomat Design Office.

Back to Emergency Steering


Sailomat History

With the unique SAILOMAT mounting base and its very compact footprint, the SAILOMAT 601 can also be mounted off-center. Off-center mounting is a desirable option that should be considered if you want to keep a swim ladder in original centered position, for yachts with 'walk-through' transoms, or for yachts with outside hung rudders, etc.

Off-center mounting up to 400 mm (16 in) is common with the SAILOMAT 601. Normally one would compensate with a slightly longer blade than for a center mounting. Self-steering performance reduction with off-center mounting is normally then insignificant.

For further details and assistance with off-center mounting, please contact SAILOMAT Design Office.

Back to Off-Center Mounting


Installation Examples

Sailomat Self-Steering Technology, delivered to over two thousand sailboats worldwide. Below is a list of installation examples and photos of the current SAILOMAT 601 model. A few earlier systems are also shown.

20'-30' LOA: Pacific Seacraft Flicka 20, Pacific Seacraft Dana 24, Maxi 77, Columbia 25, Vancouver 25, International Folkboat 26, Marieholm 26, Bianca 27, Becker 27, Freedom 28, Tartan 28, Bianca 28, Island Packet 29, Alberg 29, Hallberg Rassy 29, Contest 29, Bayfield 29, Ballad 30, Albin Alpha 29, C&C 30, Bristol 30, Catalina 30, Allegro 30, Yankee 30, Comfort 30, Scampi 30.

31'-35' LOA: Island Packet 31, Island Packet 32, Cirrus 32, Pearson 31, Cape Dory 31, Tartan 31, S&S IW 31, Pacific Seacraft 31, German Frers 31, Grampian ketch 31, Moody 31, Cal 31, Scanmar 31, Hallberg Rassy 31, L32 32, Island Packet 32, Najad 32, OE 32, Ericson 32, Comfortina 32, Pearson 33, Nor-West 33, Trimaran Dragonfly 1000 33, Allegro 33, Hans Christian 33, Scanmar 33, Meta 33, Mistral 33, Cal 33, Freedom 33, Endeavor 33, Allegro 331, Samson 33, Carter 33, She 33, Crealock 34, Mason PAE 34, Sweden Yachts 34, Cheoy Lee 34, Aphrodite 34, Hans Christian 34, Cabo Rico 34, Tartan 34, Najad 34, one off racer 34, First 34, Snowgoose 34, Dehler 34, Rival 34, Van de Stadt 34, Moen 34, Vindo 45 , Nicholson 35, Hood one off 35, J/35, Olson 34, Bristol 35, Bristol 355, Ericson 35, Hallberg Rassy 35, Baltic 35, Island Packet 35, Freedom 35, cutter one off 35, Roberts 35, Tradewind 35, Mistral 35, Contest 35, Chris Craft 35, West Conway 35, Maxi 108, Fuji ketch 35, 33' Japan-built custom catamaran.

36'-40' LOA: Pearson 36, Catalina 36, Pipedream 36, Oceanic 36, Two-Star 36, Omega 36, C&L 36, one off steel 36, Scorpion 36, Hallberg-Rassy 36, S&S one off 36, Najad 361, OE 36, Swan 36, Cal 36, Cosmos 36, Advance 36, Gin Fizz 36, Princess ketch 36, Swan 37, Alberg Whitby 37, Crealock 37, C&C 37, Rafki cutter 37, Norlin 37, Tayana 37, Tartan 37, Sancerre 37, Amazon 37, Greenland cutter 37, Bostrom 37, Fantasi 37, Furia 37, Motiva 37, Evasion 37, Moody 376, Moody 37, Sweden Yachts 38, Cabo Rico 38, Liberty 38, Sabre 38, Island Packet 38, Freedom 38, Dehler 38, Downeaster 38, Ingrid 38, Sun Fizz 38, Cheoy Lee 38, C&C 38, Vagabond 38, Hood 38, Hallberg Rassy 38, Ericson 38, Potlatch trimaran 38, Dufour 39, Euros 39, J/39, J/120, Nicholson 39, VIA 39, Drabant yawl 39, Corbin 39, Southern Cross 39, Peterson 39, Gecco 39, Mariner 39, Moen 39, Admiralty 39, Hunter 39, W Atkin ketch 39, Baltic 39, C&C 39, S&S 40, Passport 40, S&S IW, Colin Archer 40, Bowman 40, H.C. Christina 40, custom 10 ton 40' cutter, Verity 10 ton 40, Centurion 40, Tartan 40, Hunter 40, one off aluminium ketch 40, Lady Helmsman 40, Jeanneau 40, Vindo 40, Freedom 40, Swan 40, Colin Archer -Norway-27 ton 40, Beneteau First 405.

41'-45' LOA: Sweden Yachts 41, Comfort 41, Cayenne 41, Lord Nelson 41, Gulfstar 41, Amel Sharki 41, Morgan Out Island 41, Taiwan Clipper 41, S&S 42, Hallberg Rassy 41, First 405, Kettenburg 11 ton 41.5, Cheoy Lee 42, Pearson 42, Peterson 42, Cascade 42, Calv schooner 42, Perry one off 42, CT Formosa 42, Aphrodite 42, Tartan 42, Baltic 42, Baltic DP42, CT ketch 42, Hallberg Rassy 42, Centurion 42, Whitby 42, Tayana Vancouver 42, Tayana 42, Valiant 42, First 42, Pearson 424 ketch, Cal 42, Niagara 42,Taswell 42, King's Legend 41, custom aluminum sloop (aluminum, France) 42, Hunter Legend 43, one off ketch 43, C&C 43, Mason 43, Slocum 43, Sun kiss 43, Norfolk Cutter 43, Swan 43, Swan 431, Taswell 43, Nicholson 43, Saga 43, Peterson 44, Joule 44, LaFitte 44, Hylas 44, Mercer 44, Beneteau Oceanis 440, one off steel 18 ton 44, Furia 44, Mason/PAE 44, Sun Odyssey 44, Jespersen alu 15 ton, one off cutter 44, one off ketch 18 ton 44, one off alu racer 44, Swan 44, Nicholson 44, Bruce Roberts 44, Passport 44, one off steel yawl 44, Columbia ketch 45, Beneteau 45, Wasa 45, Ramrod 45.

46'-50' LOA: Swan 46, Frers 46, Walters one off 46, S&S one off 46, Sea Star 46, Kelley Peterson 46, Grand Soleil 46, one off steel 46, one off staysailschooner 46, Ericson 46, Cal 2 46, Hylas 47, Passport 47, one off Taiwan 16 ton 47, Jeanneau 47, Tayana 47, Cheoy Lee-Pedrick 47, Swan 47, Peterson 47, Perry 47, Suncoast 48, one off cutter 48, Jeaneau Trinidad 48, Celestial 48, Hans Christian 48, steel cutter 45000 lbs 48, one off cutter 48, Hallberg Rassy 49, Kees Koopman steel bermudan 25 ton 49, Bowman 49, *single-handed 1 year winter stay Antarctic expedition & Greenland-Amyr Klink Brazil- one off steel ketch 50, one off steel ketch 50, FD-12 50,one off schooner 50, Koopmans 50, S&S one off 50, D Presles (France) steel ketch 22,5 ton 50, custom 50' staysail schooner, custom 50' (51,000 lbs) ketch.

51'- 65' LOA: Swan 51, Skye Mao Ta 51, First 51, Beneteau 51, Wasa Atlantic 51, one off steel 51, Frers one off 51, Formosa 51, Skye 51, BOC racer 52, Nordia 52, Swan 53, Pearson 53, Mason 53, Van de Stadt one off 15 ton 53, Gallant 53, one off ketch 54, one off 25 ton 54, Islander schooner 22 ton 54, one off 30 ton 55, one off 25 ton 55, Tayana 55, Oyster cutter 25 ton 55, aluminum cutter (Bermuda) 55, one off 57, aluminum one off (Argentina) 15 tons 57, one off Brigantine/ staysailschooner 58, one off ketch (Argentina/tiller) 58, one off racer 60, one off 16 ton 60, Globe Challenge racer 60, one off ketch 62, one off ketch 63, one off 65, one off 51' custom sloop Antarctic research vessel (Klink/Brazil 2002), Sweden oceanic reseach vessel 'Searcher' 59'.

Back to Installation Examples

Copyright © 2017 Sailomat. All Rights Reserved.