Add-On Steering Systems

Sterndrive Hydraulic Cylinders

HYDRAULIC CYLINDERS or sometimes called rams are the primary consideration in hydraulic steering systems as they are where the action is! All the hydraulic force of the system is converted to linear motion as the cylinder extends and retracts, moving the sterndrive or outboard. At Latham Marine, we produce high quality, rugged stainless steel thick wall cylinders with incredibly smooth bores using computer controlled precision manufacturing techniques, proven by years of offshore victories and trouble free operation. All cylinders are pressure tested before shipping, to assure you of dependable, trouble free operation.

The Sterndrive Cylinder

THE STERNDRIVE CYLINDER is equipped with a stainless steel transom mount and integral clevis joint which allows pivoting action in two planes. Fluid ports are 1/4″ NPT and four standard stroke lengths are available, with a choice of polished or white powder coat transom mounts. All part numbers are for one cylinder and mount assembly. Some applications require multiple cylinders – consult your sales specialist.

STERNDRIVE CYLINDER PART NUMBERS

Stroke	Standard Clevis Joint / Polished Mount	Medium Clevis Joint / Polished Mount
7″	KRSD-9384	KRSD-9388
8″	KRSD-9385	RSD-9389
9″	KRSD-9386	KRSD-9390
10″	KRSD-9387	KRSD-9391

Stroke	Standard Clevis Joint / White Mount	Medium Clevis Joint / White Mount
7″	KRSD-9508	KRSD-9512
8″	KRSD-9509	KRSD-9513
9″	KRSD-9510	KRSD-9514
10″	KRSD-9511	KRSD-9515

Sterndrive Mounting Plates

MANY PERFORMANCE STERNDRIVE INSTALLATIONS require special mounting plates and brackets to connect external steering and tie bars. All LATHAM sterndrive plates are made from 316 stainless, computer machined for accurate fit, and polished for long lasting beauty. Attaching hardware is included unless otherwise noted.

ALPHA® MOUNT

The original MCM I drive has been revised several times; first as the Alpha Drive and now the Generation II. All kits include mounting bolts and spacers.


PLSD-2773	ALPHA, STEERING/TIE BAR PLATE
PLSD-8517	GENERATION II TIE BAR PLATE
PLSD-8518	GENERATION II STEERING AND TIE BAR PLATE

BRAVO® MOUNT

MerCruiser’s Bravo drive has been the standard on virtually every brand of performance boat for almost two decades. The Bravo drive is also available in the Bravo One X® and XR® models for higher power applications and requires a different steering mount. The LATHAM BRAVO BOLT-ON STEERING MOUNTS are bolted directed onto the stock drive requiring no removal of the stock rear cover or drainage of the drive oil. Mounting studs and lock nuts are included for increased strength.

TRS® REAR MOUNT

The TRS drive brought offshore powerboating to the masses in the 1970’s. This tough sterndrive is still on a lot of transoms, and still going fast! LATHAM’S TRS REAR MOUNT attaches over the stock rear cover on studs (studs and lock nuts are included). Fits stock TRS, TR2, and TRS Speedmaster and allows attachment of rams and/or clevis tie bars.


PLSD-2150	MCM TRS REAR MOUNT

MCM III®, IV® and V® WING AND WRAP PLATES

These drives have been used successfully in offshore racing since the ’60’s. Speedmaster became a familiar term if you wanted to stay competitive. All these drive variations share the same bolt pattern for attaching plates to the Merc rear steering cover. The correct combination of plates is primarily determined by application; i.e. hull type, racing or pleasure, etc. Special wing plates are required for drives on extension boxes, and the cylinders must have medium clevis joints. Call your sales consultant for details.


PLSD-2190	WRAP-AROUND PLATE, CENTER
PLSD-2200	WRAP-AROUND PLATE, OUTSIDE
PLSD-2210	ONE WING WRAP-AROUND PLATE

TIE BAR PLATES

TIE BAR PLATES for IV and V drives bolt to back of driveshaft housing above rear anchor pin. Mounting studs and lock nuts are included (machining of housing is required).


PLSD-2240	MCM V TIE BAR PLATE FOR LRG. CLEVIS

MERCRUISER VI® & 6A® TIE BAR MOUNTS

MERCRUISER VI® & 6A® TIE BAR MOUNTS provide solid mounting points for a clevis tie bar. Built of 316 stainless steel, they attach to the four studs built into the VI drive, or to the top of the 6A drive. Bolt kits to attach tie bar clevis joints to mounts are included.

KONRAD 540 HP STERNDRIVE® STEERING / TIE BAR PLATE

KONRAD 540 HP STERNDRIVE® STEERING / TIE BAR PLATE is designed to bolt directly to the 4 bolt holes on the rear cover without any modification to the drive. It is a universal design allowing attachment of either single or dual rams and a tie bar attaching hole on the drive center allowing smooth synchronization of multiple drives.


KPLT-7974	KONRAD DRIVE STEERING MOUNT KIT

Mercruiser Alpha, Bravo One, Bravo One XR, Bravo One XZ,TRS, III, IV, V, VI & 6A are all registered trademarks of the Brunswick Corporation. Konrad 540 HP Sterndrive is a registered trademark of Konrad Marine.

Sterndrive Tie Bars Assemblies

ALL MULTIPLE DRIVE INSTALLATIONS require one or more tie bars to keep the drives parallel and equalize loading. Boats running 65 mph or more with multiple sterndrives should use an external tie bar assembly; either in addition to an internal tie bar or by itself, if used in conjunction with Latham external steering. Using only an external clevis bar will allow the driver greater latitude for independent trimming and tilting without damage to tie bar or drive components. The same principles apply to outboards with front and rear tie bars.

LATHAM MARINE INC. TIE BARS are constructed from 316 stainless steel and satin finished for maximum corrosion resistance. Solid bars are used up to 36″ long. And tubular construction is utilized for longer bars.

CLEVIS JOINT BARS

CLEVIS JOINT BARS are available with four sizes of clevis joints in solid or tubular bars. Special bolt kits MUST be used with clevis joints.

CLEVIS JOINT BARS

TUBULAR BARS

CLEVIS JOINT TIE BAR ASSEMBLIES

* Long Anchor Pins Required

ROD END TIE BAR ASSEMBLIES

BRAVO® MOUNT

TIE BAR SADDLES can be purchased separately as replacement items. All tie bar saddles are made from 316 stainless and mirror polished, and can be ordered for rod ends or clevis joints. Heavy duty saddles for MCM TRS, III, IV and V drives require long anchor pins (sold separately). IV & V drives cannot use saddles with 1″ drive spacers.

WARNING: WHEN USING TIE BARS, DRIVES MUST BE TRIMMED AND TILTED TOGETHER TO AVOID DAMAGE TO TIE BARS OR DRIVES

LATHAM MARINE CLEVIS JOINTS

LATHAM MARINE CLEVIS JOINTS allow sterndrives or outboards to be trimmed and tilted independently to a much greater extent than typical spherical rod ends. Constructed of stainless steel to exacting tolerances, clevis joints must be used with special bolt kits to provide the proper fit on the clevis poly bushings. Four sizes of male clevis joints are available depending on duty level, and clevis joints are supplied as an integral part of the steering cylinders. Scissors clevis joints are used on triple applications where two tie bars meet at a center point, and allow both bars to attach right on the drive’s centerline.

WARNING: WHEN USING TIE BARS, DRIVES MUST BE TRIMMED AND TILTED TOGETHER TO AVOID DAMAGE TO TIE BARS OR DRIVES

LATHAM MARINE ROD ENDS

LATHAM MARINE stocks a large supply of stainless steel, Teflon lined spherical rod ends. These are available in standard AHT SERIES or heavy duty ART SERIES, and are made from several different grades of stainless. Thread size and hole size are the same, and all threads are National Fine Thread.

STANDARD SERIES

ART SERIES - HEAVY DUTY

* PLEASE NOTE: Jam nuts sold separately.

Mercruiser MCM I, Alpha, Alpha Generation II, Bravo One, Bravo One XR, Bravo One XZ,TRS, III, IV, V, VI & 6A are all registered trademarks of the Brunswick Corporation. Volvo SX, DPS and DPX are all registered trademark of Volvo Penta of the Americas, Inc.

Sterndrive Bolt Kits

ATTACHING HARDWARE

ATTACHING HARDWARE – Steering rams, mounting plates and tie bars require special bolts and spacers to attach them to plates or mounts. Clevis joints require stepped bolts with the exact length to allow proper operation and prevent damage to the clevis bushings.

Mercury Controller Valve

LATHAM ADD-ON STEERING SYSTEMS

LATHAM ADD-ON STEERING SYSTEMS are a good compromise between and an economical steering system for boats with Mercruiser® sterndrives with factory power steering and the high quality and durability associated with the Latham Full Power Systems. The stock steering cable and helm diverts the hydraulic flow through the Mercury® controller valve on the inner transom plate to the Latham external hydraulic cylinders. These systems include the same steering cylinders, mounting brackets, tie bars and attaching hardware as in the full power systems. Steering effort is low, but there is no valve to lock out propeller torque and the system is not as responsive as the full power system. The stock Mercury® controller valve requires modification by Latham Marine to be used in the ADD-ON configuration.

LATHAM ADD-ON STEERING SYSTEMS

LABR-2000 MODIFICATION TO CONTROLLER VALVE

Mercruiser and Mercury are registered trademarks of the Brunswick Corporation.