Vibration isolation for mounting water jet propulsion unit to hull

A jet-propelled boat comprising:

• a hull having a generally planar portion;
• a duct mounted to said hull, said duct comprising a generally planar mounting flange extending radially outward from said duct;
• an impeller rotatable within said duct;
• and
• a generally planar vibration isolator placed between and in contact with said generally planar portion of said hull and said generally planar mounting flange.

A jet-propelled boat comprising:

• a hull;
• a duct mounted to said hull, said duct comprising a mounting flange;
• an impeller rotatable within said duct;
• and
• a first vibration isolator placed between and in contact with a first portion of said hull and said mounting flange,
• wherein said first portion of said hull comprises an opening, and said first vibration isolator comprises an opening aligned with said opening in said hull, further comprising a fastener coupled to said mounting flange and penetrating said opening in said first portion of said hull and said opening in said first vibration isolator, wherein a portion of said first vibration isolator protrudes inside said opening in said first portion of said hull.

A jet-propelled boat comprising:

• a hull;
• a duct mounted to said hull, said duct comprising a mounting flange;
• an impeller rotatable within said duct;
• and
• a first vibration isolator placed between and in contact with a first portion of said hull and said mounting flange,
• wherein said duct comprises an inlet adapter comprising an inlet housing and said mounting flange, and an impeller housing fastened to said inlet adapter, further comprising a second vibration isolator placed between and in contact with a second portion of said hull and said inlet housing of said inlet adapter.

A compound seal comprising:

• a generally planar layer of flexible material having a peripheral edge forming a generally U-shaped opening;
• a generally U-shaped bead made of flexible material, the shapes and sizes of said U-shaped opening and said U-shaped bead being generally similar, said bead lying generally parallel to said layer and separated therefrom, and said bead being generally aligned with and overlying said peripheral edge of said layer when viewed from in front of said bead along a line of sight generally perpendicular to said layer;
• and
• means for connecting said bead to said layer.

A jet-propelled boat comprising:

• a hull;
• an inboard motor;
• a shaft driven by said motor, said shaft penetrating said hull;
• a duct mounted to said hull;
• an impeller rotatable within said duct;
• a flexible coupling for coupling said impeller to said shaft;
• and
• means for isolating said hull from vibrations in said duct during rotation of said impeller.