Attwood Catalog 2025

26 WATER SYSTEMS

attwoodmarine.com

Stainless Steel Thru-Hulls & Scupper Valve Fittings

Polish your image with these beautiful, durable stainless steel fittings. Each Thru-Hull and Scupper Valve is available with a new silicone gasket and are backed by Attwood’s trusted Lifetime Warranty! Why specify plastic parts when these fittings will last the life of the boat? Rugged Stainless Construction • Cast from certified Enhanced 316 Stainless Steel alloy for strength and lifetime corrosion-resistance • We polish all visible areas to a mirror finish, then passivate each part for additional protection • Thick steel sidewalls withstand continual stress and hose flexing Faster, Simpler Installation • A channel under the flange holds a bead of sealant, making it easier to apply a trouble-free seal • All models have wrench flats or an end notch to hold as a gripping surface. One installer can tighten all connections from inside the hull • Barbed tail ends provide plenty of room to hold multiple clamps

Stainless Steel Straight Thru-Hulls, Barbed • Standard Thread model has full-length thread for thick hulls and easy tightening

• Short Thread is a more compact size. Allows installation near corners and in confined areas. Caution: Stainless Steel Scupper Valves are designed for installation above the water line only.

66540G

B

C

B

C

A

A

D

E

D E F

Dia. B

Dia. B

F

Short Length

Standard Length

66542

A Hose Size

B Flange Dia.

C Thread O.D.

D Thread Length

E Barb Length

F Total Length 2-1/4" 2-1/2" 2-1/2" 2-1/2" 2-5/8" 3-1/8" 3-3/4" 3-3/4" 3-7/8" 3-7/8" 4-1/4" 4-1/8" 4-5/8"

Install. Hole Saw Size

Max Hull Thick.

OEM Part # without Gasket

Thread NPSM

Part #

Short Length 5/8" I.D.

66540-1 66540-3 66541-1 66541-3 66542-1 66542-3 66543-1 66543-3 66544-1 66544-3 66545-1 66545-3

1-7/8" 1" 1-7/8" 1"

1" 1"

1" 1" 1" 1" 1"

1-1/8" 1-1/8" 1-1/2" 1-1/2" 1-3/4"

3/4" 3/4"

5/8" 5/8" 5/8" 5/8" 5/8" 5/8"

3/4" I.D.

1" I.D.

2-1/4" 1-3/8" 1-1/8"

1" 1"

1-1/8" I.D. 2-1/4" 1-3/8" 1-1/4" 1-1/4" I.D. 2-1/4" 1-5/8" 1-1/4"

1-1/4" 1-1/2"

1-1/2" I.D. 3"

1-7/8" 1-1/4"

1-1/2"

2"

66546G

Standard Length 5/8" I.D.

1-1/16" 66546-1 66546-3

1-7/8" 1" 1-7/8" 1"

2" 2"

1-1/4" 1-1/4" 1-1/4" 1-1/4" 1-1/4" 1-1/4" 1-3/4"

1-1/8" 1-1/8" 1-1/2" 1-1/4" 1-3/4"

3/4" 3/4"

66547-1 66547-3 66548-1 66548-3 66549-1 66549-3 66550-1 66550-3 66551-1 66551-3

3/4" I.D.

1-5/8" 1-3/4" 1-3/4" 1-7/8" 1-7/8"

1" I.D.

2-1/4" 1-3/8" 2-1/4"

1" 1"

1-1/8" I.D. 2-1/4" 1-3/8" 2-3/8" 1-1/4" I.D. 2-1/4" 1-5/8" 2-1/2"

1-1/4" 1-1/2" 1-1/2"

1-1/2" I.D. 3"

1-7/8" 2-1/2" 2-3/8" 2-1/2"

2"

66552-1

2" I.D.

3"

2-1/2"

2"

66548

CA WARNING: Handling recreational marine vessel parts can expose you to chemicals such as phthalates and lead, which can cause cancer and reproductive harm. To minimize exposure, service the vessel outdoors or in a well-ventilated area, wear gloves, and wash your hands. For more information see www.P65Warnings.ca.gov/marine-vessel-parts.

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