# US 4,393,802 A · Boat hull with underside channel

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- Number: US 4,393,802 A
- Document ID: US4393802A
- Status: Granted
- Kind: A
- Application number: 06/150,338
- Filed: 1980-05-16
- Granted: 1983-07-19
- Earliest claimed: 1980-05-16
- Inventors: Salvatore A. Rizzo
- Web page: https://patentgrep.com/patent/US4393802A

## CPC

- B63B 1/38: using air bubbles or air layers {gas filled volumes (waterborne vessels travelling on air cushions B60V3/06)}
- Y02T 70/10: Measures concerning design or construction of watercraft hulls
- B63B: SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING (arrangements of vessel ventilation, heating, cooling, or air-conditioning B63J2/00; floating substructures as supports of dredgers or soil-shifting machines E02F9/06)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A motor boat hull is provided with a longitudinal channel formed in the central portion of the underside surface, starting at an intermediate location and terminating at the stern. Exhaust gases from the propulsion engine are introduced into the forward portion of the channel and the gases flow toward the stern thereby reducing the contact of the hull with the water and reducing the hull-to-water friction levels and reducing the power required to propel the hull at a given speed.

## Claims

### Claim 1

A hull for a motor boat having an internal combustion propulsion engine comprising a first pair of spaced apart vertical wall portions disposed on the undersurface of said hull and extending longitudinally with respect to said hull, a second pair of spaced apart vertical wall portions extending transversely with respect to said hull, with a first of said second pair of wall portions disposed at an intermediate location between the bow and the stern of said hull and with a second of said second pair of wall portions disposed proximate to said stern of said hull, a horizontally disposed wall portion extending between said first and said second pair of wall portions and with said first pair of wall portions, said second pair of wall portions and said horizontal wall portion, in combination defining a longitudinal cavity which projects inwardly into said hull, a plurality of exhaust ports disposed on said first wall of said second pair of wall portions, with said exhaust ports directed longitudinally with respect to said hull and directed toward said stern and connection means connecting said exhaust ports with said propulsion engine for the purpose of introducing exhaust gases into said cavity in order to reduce hull-to-water friction, a pair of longitudinal keel members disposed, one each, on port and on starboard sides of said cavity, with lower surfaces of said keel members including a longitudinally grooved portion, and connection means disposed to introduce exhaust gases from said propulsion engine into forward portions of said keel members.

### Claim 2 (depends on 1)

A hull according to claim 1 in which said second wall of said second pair of walls is shorter in height than said first pair of longitudinal walls and said first wall of said second pair of transverse walls.

### Claim 3 (depends on 1)

A hull according to claim 1 in which said second wall of said second pair of walls includes a streamlined fairing portion blending said second wall with said horizontal wall.

### Claim 4 (depends on 1)

A hull according to claim 1 further comprising a plurality of longitudinal ribs projecting downwardly from said horizontal wall and located, one each, between said exhaust ports.

### Claim 5 (depends on 1)

A hull according to claim 1 in which said connection means connect said exhaust ports individually, one each, to a cylinder of said propulsion engine.

### Claim 6 (depends on 1)

A hull according to claim 1 in which said keels and below water portions of said hull are manufactured of relatively dense polyurethane foam and sides of said hull are manufactured of relatively less dense polyurethane foam.

### Claim 7 (depends on 6)

A hull according to claim 6 in which said hull further comprises a deck and cabin structure manufactured of a relatively low density polyurethane foam.

### Claim 8

A hull for a motor boat having an internal combustion propulsion engine comprising a first pair of spaced apart vertical wall portions disposed on the undersurface of said hull and extending longitudinally with respect to said hull, a vertical wall portion extending transversely with respect to said hull, disposed at an intermediate location between the bow and the stern of said hull, and sealing means disposed proximate to said stern and with said sealing means comprising a flexible envelope, a source of pressurized gas, and inflation means connected to said source of gas for inflating said flexible envelope, when in use, a horizontally disposed wall portion extending between said first pair of wall portions and said vertical wall portion and said sealing means with said first pair of wall portions, said vertical wall portion, said sealing means, and said horizontal wall portion, in combination, defining a longitudinal cavity which projects inwardly into said hull, a plurality of exhaust ports disposed on said vertical wall portion, with said exhaust ports directed longitudinally with respect to said hull and directed toward said stern and connection means connecting said exhaust ports with said propulsion engine for the purpose of introducing exhaust gases into said cavity in order to reduce hull-to-water friction; and a pair of longitudinal keel members disposed, one each, on port and on starboard sides of said cavity, with lower surfaces of said keel members including a longitudinally grooved portion, and connection means disposed to introduce exhaust gases from said propulsion engine into forward portions of said keel members.

### Claim 9 (depends on 8)

A hull according to claim 8 in which said inflation means comprises pipe connection means leading from said propulsion engine to said flexible envelope for inflation of said flexible envelope using a portion of said exhaust gas and in which said flexible envelope includes at least one bleed hole permitting the escape of said exhaust gas.

### Claim 10 (depends on 8)

A hull according to claim 8 in which said flexible envelope further includes a solid bottom plate.

### Claim 11 (depends on 8)

A hull according to claim 8 restraint means urging said flexible envelope to a generally vertical position.

### Claim 12 (depends on 11)

A hull according to claim 11 in which said restraint means comprise a plurality of cables each having a first end and a second end with said first ends connected to said hull at a point forward of said flexible envelope and with said second ends connected to a generally aft portion of said flexible envelope.