Patent US4079688A successfully refreshed from Google Patents.
US4079688A
Expired / Lapsed
US
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Displacement hull
Assignee: Individual
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Filing: 1976-08-12
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Granted: 1978-03-21
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Expires: 1996-08-12
Abstract
Abstract A low-drag hull for high-speed displacement type water-craft is constructed with a constant-section keel-less midbody having a length equal to or greater than one-third of the waterline length of the hull, and with a run of less than one-sixth of the hull length. The balance of the hull comprises a slender entry defined by a linear basal ramp extending at the centerline for at least one-half of the length of the entry. The ramp slope is chosen in the range between 10:1 and 18:1. The parallel midbody is constructed with a full cross-section, the section coefficient being always greater than .785, and the ramped entry conforms, within the limits established by the need to fair in the bow and transition sections, to the sectional character of the midbody. The hull form shows a low wetted surface coefficient and sharply reduced wave-making resistance in the range between Froude numbers of 0.60 and 1.20.
Inventors
- 👤 George L. Diry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:08
CPC Classifications
B; B63; B63B; B63B1/00; B63B1/02; B63B1/04; B63B1/10
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
135 words
A fully bouyant bilaterally symetrical displacement hull for high-speed waterborne craft comprising an entry, a constant section midbody, and a run, said hull having a wetted portion which extends along the length of the hull wherein: said constant section midbody extends over at least one third of the wetted length of the hull; the wetted portion of said run extends over not more than one-sixth of the total wetted length of the hull; and the wetted portion of said entry has an upwardly and forwardly curving prow portion and a wetted length comprising the balance of the wetted length of the hull but not less than one-third of that length, with the basal surface of said entry defined by a linear ramp extending over not less than one-half of the wetted length of the entry.
Claim 2
Dependent Claim
135 words
A fully bouyant bilaterally symetrical displacement hull for high-speed waterborne craft comprising an entry, a constant section midbody, and a run, said hull having a wetted portion which extends along the length of the hull wherein: said constant section midbody extends over at least one third of the wetted length of the hull; the wetted portion of said run extends over not more than one-sixth of the total wetted length of the hull; and the wetted portion of said entry has an upwardly and forwardly curving prow portion and a wetted length comprising the balance of the wetted length of the hull but not less than one-third of that length, with the basal surface of said entry defined by a linear ramp extending over not less than one-half of the wetted length of the entry.
Claim 3
Dependent Claim
25 words
The hull of claim 1, wherein said ramp is defined by a ramp angle of from 3° to 6°, and preferably between 3.5° and 4.25°.
Claim 4
Dependent Claim
36 words
The hull of claim 2, wherein said midbody has a transverse section coefficient of not less than 0.785, as defined by its wetted perimeter, and wherein the curvature of said perimeter is convex at all points.
Claim 5
Dependent Claim
41 words
The hull of claim 3, wherein said linear ramp is preceded at its foremost portion by an upswept prow extending over not more than about 30% of the wetted entry length, and preferably over about 20% of the wetted entry length.
Claim 6
Dependent Claim
23 words
The hull of claim 4, wherein the prismatic coefficient of the hull is at least 1.2 times the prismatic coefficient of the entry.
Claim 7
Dependent Claim
22 words
The hull of claim 5, wherein the prismatic coefficient thereof is between 1.35 and 1.65 times the prismatic coefficient of said entry.
Claim 8
Dependent Claim
26 words
The hull of claim 3, wherein transverse sections through at least the aft two-thirds of said entry are similar to the transverse section of said midbody.
Claim 9
Dependent Claim
53 words
The hull of claim 5, wherein the product of the prismatic coefficient of the hull multiplied by the wetted length of the hull and divided by the product of the prismatic coefficient of the wetted length of the entry and the wetted length of the run gives a non-dimensional coefficient greater than 7.0.
Claim 10
Dependent Claim
16 words
The hull of claim 8, wherein the value of said non-dimensional coefficient is greater than 10.0.
Claim 11
Dependent Claim
168 words
A high-speed waterborne marine craft including a pair of displacement hulls for operation at Froude numbers greater than 0.55, wherein: each of said hulls is bilaterally symetrical and comprises an entry, a constant section midbody, and a run said hulls each having a wetted portion extending along the length of the hull; the wetted portion of said constant section midbody extends over at least one-third of the wetted length of said hull; the wetted portion of said run extends over not more than one-sixth of the total wetted length of said hull; the wetted portion of said entry has an upwardly and forwardly curving prow portion and a wetted length comprising the balance of the wetted length of said hull but not less than one-third of that length, with the basal surface of said entry defined by a linear ramp extending over not less than one-half of the wetted length of the entry; and the hull spacing is less than 25% of the waterline length of said hulls.
Claim 12
Dependent Claim
168 words
A high-speed waterborne marine craft including a pair of displacement hulls for operation at Froude numbers greater than 0.55, wherein: each of said hulls is bilaterally symetrical and comprises an entry, a constant section midbody, and a run said hulls each having a wetted portion extending along the length of the hull; the wetted portion of said constant section midbody extends over at least one-third of the wetted length of said hull; the wetted portion of said run extends over not more than one-sixth of the total wetted length of said hull; the wetted portion of said entry has an upwardly and forwardly curving prow portion and a wetted length comprising the balance of the wetted length of said hull but not less than one-third of that length, with the basal surface of said entry defined by a linear ramp extending over not less than one-half of the wetted length of the entry; and the hull spacing is less than 25% of the waterline length of said hulls.
Claim 13
Dependent Claim
18 words
The craft of claim 10, wherein said hull spacing is between 10% and 20% of the waterline length.
Claim 14
Dependent Claim
34 words
The craft of claim 10, wherein each of said hulls produces a wetted surface coefficient for a base beam/draft ratio of smaller than 14.75 in British units, and smaller than 2.50 in non-dimensional units.
Claim 15
Dependent Claim
20 words
The craft of claim 10, wherein the longitudinal center of flotation is located forward of the longitudinal center of buoyancy.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-03-20 | 1981-09-19 | 1982-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-20 | 1985-09-19 | 1986-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-20 | 1989-09-19 | 1990-03-21 | $7700.00 | Window Closed / Lapsed |