Over-the-Stern Deep Digging Trenching Plow with Instrumentation for Assessing the Protective Capabilities of a Seabed Trench

Abstract

A seabed trenching plow has a chassis, a sled and a towing assembly. The towing assembly has a pair of wings extending laterally from each side of the chassis. The wings are aligned on an axis transverse to the chassis and adapted for connection to a towing line. The transverse axis is forward of the center of gravity of the plow and rearward of the sled, affording an over the stern releasable and retrievable trenching plow of sufficient weight and strength to excavate a three meter trench in a single pass. To assess the protective capabilities of the trench, a threshold signal indicative of a desired composition of seabed-trench soil is compared with a real-time data signal indicative of the actual to produce an alarm signal when the real-time data signal is not protective-capability compliant with the threshold signal.

1 . A trenching plow comprising:
 a. a chassis comprising a longitudinal axis, comprising:
 i. a forward end and a rear end, the chassis defining a first axis extending from the forward end to the rear end and a second axis extending transversely to the first axis; 
 ii. a nose plate; 
 iii. a chassis nose; 
 iv. a horizontal end portion; and 
 v. an end plate disposed opposite the nose plate with respect to the longitudinal axis; 
   b. a sled connected to the forward end of the chassis below the nose at a connection point by uprights, the second axis further oriented forward of a center of gravity of the seabed trenching plow and rearward of a connection point of the uprights to the chassis;   c. a plow share mounted against a bottom of the horizontal end portion of the chassis, the plow share comprising a tip towards the nose plate;   d. a set of moldboards connected to the chassis; and   e. a towing assembly disposed at a predetermined location intermediate the chassis nose and the horizontal end portion.   
     
     
         2 . The trenching plow of  claim 1 , wherein a bottom of the chassis lies in fore and aft horizontal planes with an intermediate plane angled downwardly fore to aft. 
     
     
         3 . The trenching plow of  claim 1 , wherein:
 a. the chassis comprises three elongated vertical plates spaced by transverse vertical reinforcing plates and extending from a nose plate to an end plate; and   b. the set of moldboards are mounted against outer aft-most faces of the vertical elongated plates.   
     
     
         4 . The trenching plow of  claim 3 , wherein the chassis further comprises:
 a. a convex nose beginning at the top edge of the nose plate and transitioning into a downwardly angled midsection; and   b. a horizontal end section extending from the downwardly angled midsection to the top edge of the end plate.   
     
     
         5 . The trenching plow of  claim 4 , further comprising:
 a. a set of slid skids;   b. a set of chassis nose brackets mounted on the underside of the nose;   c. a set of uprights pivotally pinned between the sled skids and the chassis nose brackets mounted on the underside of the nose; and   d. a reinforcing strut pivotally pinned between the uprights and the angled midsection of the chassis.   
     
     
         6 . The trenching plow of  claim 5 , wherein:
 a. the set of sled uprights and the reinforcing strut are apertured and pinned to permit adjustment of a vertical distance between the chassis nose and the angle of the uprights with respect to vertical distance; and   b. the set of sled uprights are pinned to the chassis nose brackets on a common axis.   
     
     
         7 . The trenching plow of  claim 4 , wherein the tip extends forward to approximately a point below the junction of the angled midsection of the chassis with the horizontal end portion of the chassis. 
     
     
         8 . The trenching plow of  claim 1 , wherein the tip extends downwardly from the chassis at a distance of between 1.4 meters to around three meters below the chassis. 
     
     
         9 . The trenching plow of  claim 1 , wherein the plow share comprises a weight of between more than 40 tons in air to around 100 tons or more in air. 
     
     
         10 . The trenching plow of  claim 1 , wherein the moldboards comprise:
 a. a proximal section;   b. a distal section; and   c. a hinge pin joining the proximal section and the distal section at an angled-cut end.   
     
     
         11 . The trenching plow of  claim 10 , further comprising a wedges can be inserted above or below the hinge pin so that a bottom of the moldboard distal section can be locked in either a horizontal or upwardly angled condition relative to the bottom of the proximal sections of the moldboards. 
     
     
         12 . The trenching plow of  claim 10 , wherein the moldboards further comprise:
 a. a roller configured to reduce friction when the moldboards traverse a deck of a vessel; and   b. a connecting frame configured to provide reinforcement between the distal sections of the moldboards.   
     
     
         13 . The trenching plow of  claim 6 , wherein the towing assembly is disposed on the downwardly angled midsection of the chassis aft of the connection point of the sled uprights to the chassis nose. 
     
     
         14 . The trenching plow of  claim 1 , wherein the towing assembly further comprises wings mounted against outer faces of the outer vertical elongated plates, each wing comprising a mounting ring aligned on a common axis to facilitate connection to a tow line. 
     
     
         15 . The trenching plow of  claim 14 , wherein the trenching plow comprises a center of gravity, the common axis of the towing assembly mounting rings configured to fall between the sled upright connecting axis and the center of gravity. 
     
     
         16 . The trenching plow of  claim 15 , wherein:
 a. the center of gravity is located around 15 meters aft of the sled upright connecting axis; and   b. the common axis of the towing assembly mounting rings is approximately midway between the center of gravity and the sled upright connecting axis.   
     
     
         17 . The trenching plow of  claim 15 , wherein the towing line connection assembly is located to position the common axis of the towing assembly mounting rings between the center of gravity and the sled upright connecting axis.