Underwater Gear

Keep your boat running smooth and tracking true with precision underwater gear from WaterSkis.com. Whether you're replacing a worn Mastercraft drive shaft, upgrading a Moomba rudder, or sourcing an exact-fit Supra strut, we carry genuine OEM and compatible parts built to match factory performance. This category includes critical inboard components like drive shafts, struts, rudders, and other hardware essential to your boat’s handling and power delivery.

Need to find the right part fast? Use our Boat Part Lookup Tool to identify inboard boat underwater gear for your exact year, make, and model—no guesswork required. We stock parts for top ski and wake brands, including Mastercraft, Moomba, and Supra, with quality you can trust in deep water or shallow turns.

For smooth rides and confident control, trust WaterSkis.com for the underwater gear that keeps your boat performing its best.


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  • Supra | Moomba Rudder Assembly | 426

    Supra | Moomba Rudder Assembly | 426

    Skiers Choice
    $1,269.74
    Supra | Moomba Rudder Assembly | 426 This is a complete rudder and rudder port assembly for Supra and Moomba Boats. This was used on many v-drive Supra Boats and Moomba Boats. Use the Boat Part Lookup to ensure you are getting the correct part for your...
    Qty in Cart: 0
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    $1,269.74
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  • Supra | Moomba Strut - 15 deg. 1" | 028

    Supra | Moomba Strut - 15 deg. 1" | 028

    Skiers Choice
    $682.48
    Supra | Moomba Strut - 15 deg. 1" | 028 This is a 15 Degree Strut for a 1" shaft for Supra and Moomba Boats. Short Bore. Use the Boat Part Lookup to ensure you are getting the correct part for your Supra and Moomba Boat.  
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    $682.48
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  • Supra | Moomba Drive Shaft-48"x1-1/8" | 358

    Supra | Moomba Drive Shaft-48"x 1-1/8" | 358

    Skiers Choice
    $1,031.66
    Supra | Moomba Drive Shaft-48"x1-1/8" | 358 This is a 48" Drive Shaft by 1-1/8" diameter for Supra and Moomba Boats. ***Skier’s Choice couplers are pressed onto the shaft and the assembly is CNC balanced to improve performance and reduce vibration...
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    $1,031.66
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  • MasterCraft OEM Drive Shaft 52.25" - 310 MasterCraft OEM Drive Shaft 52.25" - 310

    MasterCraft OEM Drive Shaft 52.25" - 310

    MasterCraft
    $1,269.74
    Drive Shaft 52.25" x 1-1/8" This genuine MasterCraft drive shaft is 52.25 inches long by 1-1/8 inch diameter with coupler. This drive shaft is specifically designed for MasterCraft V-Drive boats. Comes with a new prop nut and cotter pin. Designed for...
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    $1,269.74
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  • Supra | Moomba Rudder Assembly | 203

    Supra | Moomba Rudder Assembly | 203

    Skiers Choice
    $1,031.66
    Supra | Moomba Rudder Assembly | 203 This is a complete rudder and rudder port assembly for Supra and Moomba Boats. This is the 105 Degree rudder assembly. Use the Boat Part Lookup to ensure you are getting the correct part for your Supra and Moomba Boat...
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    $1,031.66
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  • Mastercraft T-Handle Bilge Drain Plug w/ O-Ring Mastercraft T-Handle Drain Plug w/ O-Ring

    Mastercraft T-Handle Bilge Drain Plug w/ O-Ring

    MasterCraft
    MSRP: $31.73
    $20.62
    Mastercraft T-Handle Drain Plug w/ O-Ring MasterCraft T-handle Bilge Drain Plug is made of Nylon and is made for fresh or saltwater marine environments and is a direct factory replacement for MasterCraft boats built from 2006-Current. This plug is...
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    MSRP: $31.73
    $20.62
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  • MasterCraft Triangle Transom Nylon Drain Plug w/ O-Ring MasterCraft Triangle Transom Nylon Drain Plug w/ O-Ring

    MasterCraft Triangle Transom Nylon Drain Plug w/ O-Ring

    MasterCraft
    $55.54
    MasterCraft Triangular Transom Nylon Drain Plug w/ O-Ring This MasterCraft Boats Transom Drain Plug is made of Nylon and is made for a marine environment and is a direct factory replacement for most MasterCraft boats built from 2006-Current. This plug is...
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    $55.54
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  • Center Drain Plug Assembly W/T-Handle Center Drain Plug Assembly W/T-Handle

    Center Drain Plug Assembly W/T-Handle

    Skiers Choice
    $68.23
    MasterCraft, Supra, Moomba Center Drain Plug Assembly W/T-Handle This MasterCraft, Supra, Moomba T Handle Boat Bilge Drain Plug is made of brass for long lasting durability in a marine environment and is a direct factory replacement for MasterCraft boats...
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    $68.23
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  • Log Shaft Packing For 1 1/8" Drive Shaft Log Shaft Packing For 1 1/8" Drive Shaft

    Log Shaft Packing For 1 1/8" Drive

    $7.92
    Log Shaft Packing For 1 1/8" Drive Wax impregnated rope for drive shaft and rudder stuffing boxes. Each piece is 3/16 diameter and 4.5" long. The 3/16 shaft packing is designed for boats with a 1 1/8" drive shaft which is commonly found on MasterCraft,...
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    $7.92
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  • Log Shaft Packing For 1" Drive Shaft Log Shaft Packing For 1" Drive

    Log Shaft Packing For 1" Drive Shaft

    $7.92
    Log Shaft Packing For 1" Drive Shaft Wax impregnated rope for drive shaft and rudder stuffing boxes. Each piece is 1/4" diameter and 4.5" long. The 1/4" shaft packing is designed for boats with a 1" drive shaft which is commonly found on 2002 and older...
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    $7.92
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  • HOSE - DRIPLESS GLAND FORMED

    Hose - Dripless Gland Formed

    MasterCraft
    $47.60
    HOSE - MasterCraft DRIPLESS GLAND FORMED Dripless gland formed hose to be used with the Glide Dripless gland. Designed to be used with 1-1/8” drive shafts and MasterCraft boats 2005 and newer. Use the boat part look up below to ensure you are...
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    $47.60
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  • Prop Nut for 1-1/4" Shafts

    Prop Nut for 1-1/4" Shafts

    OJ Props
    $47.60
    Inboard Prop Nut for 1-1/4" Shafts A simple replacement for you lost or damaged inboard prop nut. This is a universal part that fits MasterCraft, Malibu, Supra, and Nautique boats with a 1-1/4" drive shaft. Don't be a fool, keep a spare on hand...
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    $47.60
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  • OJ Prop Puller for Inboard Boats | 1-1/4" Shaft

    OJ Prop Puller For Inboard Boats | 1-1/4" Shaft

    OJ Props
    $253.95
    OJ Prop Puller for Inboard Boats | 1-1/4" Shaft Effortless Propeller Removal – Built Tough for Serious Boat Owners The OJ Prop Puller is a must-have tool for any inboard boat owner looking to remove or replace their propeller with ease and...
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    $253.95
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  • OJ SKIPRO Prop 13.9X14.25-4 Blade | Splined | Bore 1 1/8" | LH

    OJ SKIPRO Prop 13.9X14.25-4 Blade | Splined | Bore 1 1/8" | LH

    OJ Props
    MSRP: $1,047.55
    $890.42
    OJ SKIPRO Prop 13.9X14.25-4 Blade | Splined | Bore 1 1/8" | LH The OJ SKIPRO V-4 1709 4 Blade 13.9" X 14.25" LH-4 BLADE SPLINED BORE Propeller features a new blade shape and pitch distribution along with OJ's unique cupping feature for better top end...
    Qty in Cart: 0
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    MSRP: $1,047.55
    $890.42
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  • OJ SKIPRO Prop 14X13.5-3 Blade | Splined | Bore 1 1/8" | LH

    OJ SKIPRO Prop 14X13.5-3 Blade | Splined | Bore 1 1/8" | LH

    OJ Props
    MSRP: $960.26
    $816.22
    OJ SKIPRO Prop 14X13.5-3 Blade | Splined | Bore 1 1/8" | LH The OJ SKIPRO V-3 867 3 Blade 14" X 13.5" LH-3 BLADE SPLINED BORE Propeller boasts an enhanced pitch distribution along with a new blade shape that produces better top end and low end power. Use...
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    MSRP: $960.26
    $816.22
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  • OJ Evolution Prop 18X17.5-4 Blade | Splined | Bore 1 1/4" | LH

    OJ Evolution Prop 18X17.5-4 Blade | Splined | Bore 1 1/4" | LH

    OJ Props
    MSRP: $1,861.79
    $1,582.52
    OJ Evolution Prop 18X17.5-4 Blade | Splined | Bore 1 1/4" | LH The OJ Evolution 3602-MF 4 Blade 18" X  17.5" LH 4-BLADE SPLINED BORE Propeller features a complete blade shape and pitch distribution redesign. Evolving from our successful WAKEPRO and...
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    MSRP: $1,861.79
    $1,582.52
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  • OJ Evolution Prop 15X12-4 Blade | Splined | Bore 1 1/8" | LH

    OJ Evolution Prop 15X12-4 Blade | Splined | Bore 1 1/8" | LH

    OJ Props
    MSRP: $1,353.88
    $1,150.80
    OJ Evolution Prop 15X12-4 Blade | Splined | Bore 1 1/8" | LH The OJ Evolution 3043-MF 4 Blade 15" X  12" LH 4-BLADE SPLINED BORE Propeller features a complete blade shape and pitch distribution redesign. Evolving from our successful WAKEPRO and V-4...
    Qty in Cart: 0
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    MSRP: $1,353.88
    $1,150.80
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  • OJ Evolution Prop 15X13-4 Blade | Splined | Bore 1 1/8" | LH

    OJ Evolution Prop 15X13-4 Blade | Splined | Bore 1 1/8" | LH

    OJ Props
    MSRP: $1,353.88
    $1,150.80
    OJ Evolution Prop 15X13-4 Blade | Splined | Bore 1 1/8" | LH The OJ Evolution 3033-MF 4 Blade 15" X 13" LH 4-BLADE SPLINED BORE Propeller features a complete blade shape and pitch distribution redesign. Evolving from our successful WAKEPRO and V-4...
    Qty in Cart: 0
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    MSRP: $1,353.88
    $1,150.80
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  • OJ Evolution Prop 17.5X16.5-4 Blade | Splined | Bore 1 1/8" | LH

    OJ Evolution Prop 17.5X16.5-4 Blade | Splined | Bore 1 1/8" | LH

    OJ Props
    MSRP: $1,790.36
    $1,521.81
    OJ Evolution Prop 17.5X16.5-4 Blade | Splined | Bore 1 1/8" | LH The OJ Evolution 3028-MF 4 Blade 17.5" X 16.5" LH 4-BLADE SPLINED BORE Propeller features a complete blade shape and pitch distribution redesign. Evolving from our successful WAKEPRO and...
    Qty in Cart: 0
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    MSRP: $1,790.36
    $1,521.81
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  • OJ Evolution Prop 16.5X15-4 Blade | Splined | Bore 1 1/8" | LH

    OJ Evolution Prop 16.5X15-4 Blade | Splined | Bore 1 1/8" | LH

    OJ Props
    MSRP: $1,712.59
    $1,455.70
    OJ Evolution Prop 16.5X15-4 Blade | Splined | Bore 1 1/8" | LH The OJ Evolution 3027-MF 4 Blade 16.5" X 15" LH 4-BLADE SPLINED BORE Propeller features a complete blade shape and pitch distribution redesign. Evolving from our successful WAKEPRO and V-4...
    Qty in Cart: 0
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    MSRP: $1,712.59
    $1,455.70
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Adding your products to cart

WaterSkis.com makes it easy to find the exact underwater gear your inboard boat needs—from drive shafts and struts to rudders and more. With parts for Mastercraft, Moomba, Supra, and other leading brands, our Boat Part Lookup Tool helps ensure a perfect fit every time. Looking to complete your repair? Explore propellers or steering components
 for a full performance upgrade.