R&D Marine Flexible Shaft Coupling #910-003

R&D Marine Flexible Shaft Coupling #910-025

R&D Marine Flexible Shaft Coupling #910-032

R&D Marine Flexible Shaft Coupling #910-006

R&D Marine Flexible Shaft Coupling #910-026

R&D Marine Flexible Shaft Coupling #910-033

ZF-Hurth Flexible Couplings - 6" Flange

910-003

$ 720.00 USD

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Size Guide

Gearbox Model Flange Diameter Horsepower Rating Per 100 RPM

Quantity

Description

The R&D Marine Flexible Coupling consists of a flexible disc molded with a Polyester Elastomer. The disc gives clearance for bolt heads and is able to flex freely to take up any temporary misalignment of the engine and shaft due to flexing of the boat structure or the engine moving on its mount. Forward thrust is taken in compression on the disc between the two half couplings, and reverse thrust is taken again in compression on the disc between the two fail-safe straps. In the unlikely event of a severe impact, the steel straps make the coupling fail-safe and ensure the drive is maintained both forward and reverse.

Reduce Engine Noise & Transmission Vibration
Staggered bolts enable the element to isolate vibrations and compensate for some misalignment.

Reduces Costly Transmission Repairs
Absorbs shock loads due to hard gear changes.

Fits Most Major Transmissions
For engines, 5 to 1,500 horsepower. Fits brands such as Borg Warner, ZF-Hurth, Twin Disc, Volvo, Yanmar, Technodrive, and more.

Under Compression Load In Both Forward & Reverse
The aft steel strap bolted to the transmission acts as a backing plate to prevent reverse thrust from pulling the element apart.

Quick & Easy Installation
The R&D Marine Flexible Coupling requires no machining and comes supplied with bolts to connect between the two existing shaft flanges.

Extremely Durable
Impervious to saltwater, diesel, and lubrication oils. The Flexible Couplings are made from a polyester elastomer that is not affected by saltwater, diesel, or lubrication fluids.

Fail-Safe Design
A fail-safe design is incorporated in the R&D Flexible Shaft Coupling that prevents the two couplings from pulling apart in the event of an impact or element failure, whereas other couplings do not. This fail-safe design is accomplished by using two steel straps and thru-bolts going into both the shaft coupling and transmission output flange. The aft steel strap is bolted to the transmission output flange, and the front strap is bolted to the shaft coupling. In the event of an impact, the aft steel strap (bolted to the transmission) will catch the front steel strap (bolted to the shaft coupling) and prevent the drivetrain from pulling apart. The R&D element will absorb the shock load (reducing or eliminating damage to the transmission) and will maintain contact between the two couplings. The steel straps also keep the R&D Flex-Coupling under a compression load in both forward AND reverse operation (the aft strap bolted to the transmission acts as a backing plate).

R&D Marine Flexible Shaft Coupling fail safe design

Machined Not Molded
The Drivesaver is molded, while the R&D Flexible Shaft Coupling is machined. Both designs suggested that you first set your alignment by drawing the two couplings up to each other and then add the flex-coupling. The machined part will have MUCH tighter tolerance than a molded part.

Checking Alignment
The R&D Flexible Shaft Coupling allows for inspection of alignment after the element is bolted in place. There is one bolt head that is machined and painted red. After the R&D Flexible Shaft Coupling is bolted into place, a feeler gauge can be slipped between the red bolt head and the coupling. This process is repeated with the same bolt four times at 90-degree intervals by rotating the shaft. If the gap is within .010” (0.25mm), the engine is accurately aligned.

Special Orders

We keep all the common R&D Marine Flexible Couplings in stock; however, for a few of the less common sizes will have to be special ordered. Special Order Items will take approximately 2 to 3 weeks to ship out.

How To Select The Right Coupling For You

Engine horsepower and engine speed.
Type of gearbox and reduction ratio.
Gearbox flange details. Diameter of flange. Diameter of register. Pitch circle diameter of fixing holes. Size and quantity of holes. (Pitch circle diameter is the distance between the center of the hole at 12 o'clock position to the center of the hole at 6 o'clock)

Example

Ford 150hp at 2,500 rpm.
Borg Warner Velvet Drive 72C 2:1 reduction.
5" flange 2,500 diameter register, 4.250 PCD, 4 off holes 0.437 diameter

To Calculate the Power Of Coupling Required:

The coupling rating needed is 12hp. By looking at the chart below, we can determine the coupling required is a 910-009 Borg Warner.

Installation Procedure For R&D Marine Couplings

Roughly align engine and stern gear without flexible coupling i.e. only two rigid half couplings pushed together.
Bolt "R&D Marine" coupling between the two rigid couplings. Tightening details as below.
Check the alignment of the engine by placing feeler gauges between RED CONE HEADED BOLT and the rigid half coupling. Repeat for the SAME bolt at 90° intervals by rotating the shaft.
If the gap is the same in all four positions, the engine is accurately aligned. Recommended minimum to maximum gap difference: 0.010 inches.
Run the installation to bring the engine compartment to working temperature.
Re-check torque settings.

Recommended tightening torque:

M8 = 20 ft. lbs.
3/8 UNF = 30 ft. lbs.
M10 = 45 ft. lbs.
7/16 UNF = 60 ft. lbs.
M12 = 80 ft. lbs.
1/2 UNF 75 ft. lbs.
5/8 UNF = 155 ft. lbs.
M18 UNF = 250 ft. lbs.
3/4 UNF = 270 ft. lbs.

Flexible Coupling	Manufacturer	Diameter inches / mm	# of Bolts	Diameter of Holes inches / mm	Bolt Pitch Circle inches / mm	Register inches / mm	Diameter inches / mm	Length inches / mm	Bolt Diameter	HP per 100 RPM hp / kW	Ref
910-001	B/W, PRM, ZF-Hurth, Technodrive	4 / 101.6	4	0.39 / 10	3.25 / 82.55	2.5 / 63.5	4.5 / 114.3	1.28 / 32.5	M10	5 / 3.73
910-002	Yanmar	4 / 101.6	4	0.39 / 10	3.07 / 78	1.97 / 50	4.5 / 114.3	1.28 / 32.5	M10	3 / 2.24
910-003	B/W, PRM, ZF-Hurth, Twin Dsic	5.75 / 146	6	0.5 / 12.7	4.75 / 120.6	3 / 76.2	6 / 152.4	1.87 / 47.5	1/2 UNF	20 / 14.92	X O
910-004	B/W, PRM, ZF-Hurth	4 / 101.6	4	0.39 / 10	3.25 / 82.55	2.5 / 63.5	4.5 / 114.3	1.4 / 35.6	M10	8 / 5.97
910-005	Paragon	4 / 101.6	4	0.38 / 9.7	3.25 / 82.55	2.63 / 66.7	4.5 / 114.3	1.35 / 34.5	3/8 UNF	7 / 5.22
910-006	Twin Disc, ZF-Hurth	5.75 / 146	6	0.63 / 16	4.75 / 120.6	3 / 76.2	6 / 152.4	1.87 / 47.5	1/2 UNF	20 / 14.92	O X O
910-007	Volvo	4 / 101.6	4	0.39 / 10	3.15 / 80	2.36 / 60	4.5 / 114.3	1.72 / 43.7	M10	3 / 2.24
910-009	B/W, PRM, ZF-Hurth, Volvo	5 / 127	4	0.44 / 11.2	4.25 / 107.9	2.5 / 63.5	5.63 / 143	1.77 / 45	7/16 UNF	13 / 9.69	X O
910-012	Yanmar	5 / 127	4	0.39 / 10	3.93 / 100	2.56 / 65	5.31 / 135	1.77 / 45	M10	10 / 7.46
910-013	Bukh	3.54 / 90	4	0.32 / 8.1	2.93 / 74.5	1.85 / 47	4.5 / 114.3	1.28 / 32.5	M8	3 / 2..24
910-014	B/W, PRM, ZF-Hurth, Technodrive	4 / 101.6	4	0.39 / 10	3.25 / 82.55	2.5 / 63.5	4.5 / 114.3	1.28 / 32.5	M10	3 / 2.24
910-015	Self Change 350HD	8.75 / 222.2	6	0.44 / 11.2	7.5 / 190.5	6 / 152.4	8.75 / 222.2	1.75 / 44.5	7/16 UNF	43 / 32.1	O
910-016	Self Change 700HD	10.25 / 260.4	6	0.63 / 16	9 /228.6	6 / 152.4	10.88 / 276.4	2.28 / 58	5/8 UNF	65 / 48.47	X O
910-017	Twin Disc	7.25 / 184.2	6	0.75 / 19	6 /152.4	3.75 / 190.5	7.5 / 190.5	2.39 / 60.7	5/8 UNF	40 / 29.84	O X O
910-018	PRM	7.25 / 184.2	6	0.63 / 16	6 / 152.4	3.75 / 190.5	7.5 / 190.5	2.39 / 60.7	5/8 UNF	40 / 29.84	X O
910-019	Volvo	4 / 101.6	4	0.39 / 10	3.15 / 80	2.36 / 60	4.5 / 114.3	1.28 / 32.5	M10	3 / 2.24
910-020	Volvo	4 / 101.6	4	0.39 / 10	3.15 / 80	2.36 / 60	4.5 / 114.3	1.28 / 32.5	M10	5 / 3.73
910-021	Endfield, Sonic	4 / 101.6	2	0.44 / 11.2	3 / 76	-	4.25 / 108	1.64 / 41.7	7/16 UNF	2.5 / 1.87
910-022	Twin Disc	9 / 228.6	8	0.89 / 22.6	7.5 / 190.5	6 / 152.4	8.75 / 222.2	1.75 / 44.5	1/2 UNF	65 / 48.47	O X O
910-024	Twin Disc	10.5 / 266.7	8	1 / 25.4	8.75 / 222.2	5 / 127	10.88 / 276.4	2.23 / 56.7	5/8 UNF	85 / 63.38	O X O
910-025	B/W, PRM, ZF-Hurth, Twin Disc	5.75 / 146	6	0.5 / 12.7	4.75 / 120.6	3 / 76.2	6 / 152.4	1.96 / 49.8	1/2 UNF	28 / 20.88	X O
910-026	Twin Disc	5.75 / 146	6	0.63 / 16	4.75 / 120.6	3 / 76.2	6 / 152.4	1.96 / 49.8	1/2 UNF	28 / 20.88	O X O
910-027	ZF W320 320 A	8.86 / 225	8	0.67 / 17	7.72 / 196	5.51 / 140	9 / 228.6	1.75 / 44.5	1/2 UNF	65 / 48.47	O
910-028	Bukh	3.54 / 90	4	0.32 / 8.1	2.93 / 74.5	1.85 / 47	4.5 / 114.3	1.28 / 32.5	M8	5 / 3.73
910-029	B/W, ZF-Hurth, Volvo	5 / 127	4	0.44 / 11.2	4.25 / 107.9	2.5 / 63.5	5.63 / 143	2.06 / 52.4	7/16 UNF	20 / 14.92	O
910-030		11.5 / 292.1	8	1 / 25.4	9.75 / 247.6	6 / 152.4	11.5 / 292.1	2.3 / 58.4	5/8 UNF	120 / 89.48	O X O
910-032	B/W, PMR, ZF-Hurth, Twin Dsic	5.75 / 146	6	0.5 / 12.7	4.75 / 120.6	3 / 76.2	6 / 152.4	2.18 / 55.4	1/2 UNF	37 / 27.6
910-033	Twin Disc, ZF-Hurth	5.75 / 146	6	0.63 / 16	4.75 / 120.6	3 / 76.2	6 / 152.4	2.18 / 55.4	1/2 UNF	37 / 27.6	O
910-034	Open Center V Drive 52mm Bore	5 / 127	4	0.44 / 11.2	4.25 / 107.9	2.5 / 63.5	6.38 / 162	1.77 / 45	7/16 UNF	12 / 8.95	#
910-035		13.38 / 340	8	1 / 25.4	11.63 / 295.3	6 / 152.4	13.7 / 348	4.25 / 108	5/8 UNF	160 / 119.3	O
910-036	Twin Disc	5 / 127	4	0.39 / 10	4.13 / 104.8	2.5 / 63.5	5.63 / 143	1.77 / 45	M10	10 / 7.46
910-037	Yanmar	5.12 / 130	4	0.48 / 12.3	4.25 / 107.9	2.5 / 63.5	5.63 / 143	2.01 / 51.1	7/16 UNF	13 / 9.69
910-038	Taipeoungyang TK 250	7 / 178	6	0.56 / 14.3	5.98 / 152	3.94 / 100	7.5 / 190.5	2.49 / 63.3	M14	55 / 41
910-039	Twin Disc	7.25 / 184.2	6	0.75 / 19	6 / 152.4	3.75 / 190.5	7.5 / 190.5	2.49 / 63.3	5/8 UNF	55 / 41	O
910-040	PRM	7.25 / 184.2	6	0.63 / 16	6 / 152.4	3.75 / 190.5	7.5 / 190.5	2.49 / 63.3	5/8 UNF	5 /41
910-041		11.5 / 292.1	8	1 / 25.4	9.75 / 247.6	6 / 152.4	11.5 / 292.1	2.3 / 58.4	5/8 UNF	140 / 104.4	O
910-042	DONG-I DMT 170L	11.3 / 287.2	6	0.98 / 25.1	9.45 / 240	6.3 / 160	11.5 / 292.1	2.3 / 58.4	5/8 UNF	90 / 67	O
910-043	Yanmar	4 / 101.6	4	0.39 / 10	3.07 / 78	1.97 / 50	4.5 / 114.3	1.28 / 32.5	M10	5 / 3.73
910-044	B/W, PRM, ZF-Hurth, Volvo	5 / 127	4	0.44 / 11.2	4.25 / 107.9	2.5 / 63.5	5.6 / 143	1.77 / 45	7/16 UNF	8 / 5.97
910-045		13.38 / 340	8	1 / 25.4	11.63 / 295.3	6 / 152.4	13.7 / 348	4.25 / 108	3/4 UNF	230 / 171.5	O
910-046	Allison M25	9 / 228.6	8	0.75 / 19	7.5 / 190.5	6 / 152.4	8.75 / 222.2	1.75 / 44.5	1/2 UNF	65 / 48.47	O
910-047	Dong-I DMT 260H	11.5 / 292.1	6	0.826 / 21	9.45 / 240	5.9 / 150	11.5 / 292.1	2.3 / 58.4	5/8 UNF	90 / 67	O
910-048	Twin Disc MG 5111 SC	9 / 228.6	6 (8)	0.89 / 22.6	7.5 / 190.5	6 / 152.4	8.75 / 222.2	2.47 / 62.7	1/2 UNF	65 / 48.47	O X O
910-049	ZF 325-1A Volvo Flange	8.07 / 205	10	0.71 / 18	6.69 / 170	5.51 / 140	8.78 / 223	4.88 / 124	M18	75 / 56
910-050	Twin Disc 510A/5114A	9 / 228.6	8	0.89 / 22.6	7.5 / 190.5	6 / 152.4	9 / 228.6	4 / 101.6	1/2 UNF	85 / 63.38	O
910-051	Twind Disc MG 521	11 / 279.4	8	0.75 / 19	9.5 / 241.3	6 / 152.4	11.25 / 260.4	2.3 / 58.4	5/8 UNF	120 / 89.48	O
910-052	2F, 220A, Lister, Twin Disc 502	4.75 / 120.7	6	0.44 / 11.2	3.88 / 98.5	2.5 / 63.5	5.94 / 150.9	2.75 / 69.9	7/16 UNF	10 / 7.46
910-053	Dong-I DMT 150H	8.58 / 218	6	0.79 / 20	7.09 / 180	5.51 / 140	8.75 / 222.2	1.77 / 45	1/2 UNF	48 / 35.8	O
910-054	Open Center V Drive 58mm Bore	5.75 / 146	6	0.5 / 12.7	4.75 / 120.6	3 / 76.2	6.77 / 172	1.87 / 47.5	1/2 UNF	24 / 17.9
910-055	Open Center V Drive 52mm Bore	5 / 127	4	0.44 / 11.2	4.25 / 107.9	2.5 / 63.5	6.38 / 162	1.77 / 45	7/16 UNF	7 / 5.2	#
910-057	B/W, Hurth, Volvo	5 / 127	4	0.44 / 11.2	4.25 / 107.9	2.5 / 63.5	5.63 / 143	2.06 / 52.4	7/16 UNF	25 / 18.64
910-058	Dong-I DMT 70T, 90T, 100T	7 / 178	6	0.63 / 16	5.98 / 152	3.94 / 100	7.5 / 190.5	2.49 / 63.3	5/8 UNF	55 / 41
910-059	Volvo	4 / 101.6	4	0.39 / 10	3.15 / 80	2.36 / 60	4.5 / 114.3	1.4 / 35.6	M10	8 / 5.96
910-060	TMP	4.44 / 112.8	2	0.44 / 11.2	3.19 / 81	-	4.44 / 112.8	1.5 / 38.1	7/16 UNF	3.25 / 2.42
910-061	Open Center V Drive 52mm Bore	5 / 127	4	0.44 / 11.2	4.25 / 107.9	2.5 / 63.5	6.38 / 162	2.07 / 52.6	7/16 UNF	19 / 14.16
910-062	DONG-I DMT 140H	7.8 / 198	6	0.63 / 16	6.69 / 170	5.12 / 130	8.27 / 210	1.9 / 48.2	M16	63 / 47
910-063	Open Center V Drive 58mm Bore	5.75 / 146	6	0.5 / 12.7	4.75 / 120.6	3 / 76.2	6.77 / 172	2.185 / 55.5	1/2 UNF	32 / 23.8
910-064	Open Center V Drive 67mm Bore	7.25 / 184.2	6	0.63 / 16	6 / 152.4	3.75 / 190.5	9.06 / 230	2.51 / 63.8	5/8 UNF	50 / 37.3

O - These couplings are fitted with a shouldered bushing to locate in the gearbox flange.

O - These flexible couplings have been approved by Bureau Veritas.

x - These flexible couplings have been approved by Lloyds Register of Shipping.

# - For the Hurth HBW 150 V Gearbox an adapter 202-351 is required (0.875" long).

For the IRM 220A Gearbox, we can supply adapter plate 202-384 (2.125" long) and for the Twin Disc 502 Gearbox, adapter plate 202-148 (2.125" long) that bolts onto flexible couplings 910-003, 910-025 or 910-032 and with half coupling 202-037 or 202-054, alternatively clamp type 202-176 or 202-178.

ZF-Hurth Flexible Couplings - 4" Flange

Yanmar Flexible Couplings

HI ERIC, Yvette was my ex.
I am Pierre and yes it's perfect. Very good service.
Thanks again!

Shaft coupler

I was extremely pleased with this purchase and support. I believe it was Miles that helped me well done!

Excellent Customer Sevice

Ordered a part and gave them the wrong shipping address. UPSP returned the part to PYI. They resent the item for me (once I gave the them the correct address!). Very accommodating and responsive. Highly recommend PYI for top-notch customer service (not something you can say about everyone these days).