﻿OYSTERS 
  AND 
  METHODS 
  OF 
  OYSTER-CULTURE. 
  319 
  

  

  account 
  of 
  tbe 
  difficulty 
  of 
  cutting 
  grass 
  growing 
  under 
  water, 
  he 
  invented 
  in 
  1885 
  

   and 
  has 
  since 
  nsed 
  a 
  device 
  wliich 
  may 
  bo 
  termed 
  an 
  a(|uatic 
  mowing 
  machine. 
  

   The 
  machine 
  is 
  rigged 
  on 
  a 
  square-ended 
  scow 
  20 
  feet 
  long 
  by 
  8 
  feet 
  wide. 
  On 
  the 
  

   forward 
  end 
  of 
  the 
  scow 
  is 
  suspended, 
  by 
  a 
  framework, 
  a 
  double 
  set 
  of 
  knives, 
  each 
  

   set 
  being 
  similar 
  to 
  those 
  of 
  mowing 
  machines 
  used 
  l)y 
  agriculturists. 
  The 
  object 
  

   in 
  having 
  double 
  knives 
  is 
  to 
  enable 
  the 
  machine 
  to 
  cut 
  when 
  moving 
  backward 
  as 
  

   well 
  as 
  when 
  moving 
  forward, 
  thus 
  avoiding 
  the 
  necessity 
  of 
  having 
  to 
  turn 
  the 
  

   scow 
  around 
  when 
  the 
  end 
  of 
  the 
  swath 
  is 
  reached. 
  The 
  knife 
  bar 
  is 
  12 
  feet 
  long 
  

   and 
  consequently 
  cuts 
  a 
  swath 
  12 
  feet 
  wide. 
  The 
  power 
  of 
  propelling 
  the 
  machine 
  

   is 
  supplied 
  by 
  a 
  (j-horsepower 
  high-pressure 
  condensing 
  engine, 
  which 
  is 
  located 
  in 
  

   the 
  middle 
  of 
  the 
  scow. 
  A 
  line 
  1,000 
  feet 
  in 
  length 
  is 
  passed 
  with 
  three 
  turns 
  around 
  

   a 
  winch 
  head 
  and 
  drawn 
  taut 
  by 
  an 
  anchor 
  at 
  each 
  end, 
  placed 
  a 
  short 
  distance 
  

   beyond 
  the 
  extreme 
  boundaries 
  of 
  the 
  area 
  to 
  be 
  mowed. 
  It 
  is 
  held 
  in 
  position 
  by 
  a 
  

   fair-leader 
  or 
  chock 
  having 
  a 
  shivc 
  on 
  each 
  side 
  similar 
  to 
  the 
  shive 
  of 
  an 
  ordinary 
  

   tackle 
  block. 
  The 
  shives 
  facilitate 
  tbe 
  passage 
  of 
  the 
  line 
  through 
  the 
  leader 
  by 
  

   lessening 
  the 
  friction 
  and 
  corresjiondingly 
  decrease 
  the 
  wear 
  upon 
  it. 
  The 
  leader 
  

   or 
  chock 
  is 
  placed 
  on 
  the 
  forward 
  end 
  of 
  the 
  scow, 
  and 
  not 
  only 
  serves 
  to 
  hold 
  the 
  

   line 
  in 
  position, 
  but 
  also 
  keeps 
  the 
  scow 
  straight 
  in 
  its 
  course. 
  

  

  When 
  the 
  engine 
  is 
  started, 
  the 
  winch-head 
  revolves, 
  and 
  the 
  pressure 
  of 
  the 
  line, 
  

   encircling 
  it 
  in 
  three 
  turns 
  tightly 
  drawn, 
  forces 
  the 
  scow 
  through 
  the 
  water. 
  The 
  

   rate 
  of 
  speed 
  at 
  which 
  it 
  can 
  be 
  operated 
  is 
  1,000 
  linear 
  feet 
  in 
  5 
  minutes, 
  thus 
  

   enabling 
  it 
  to 
  mow 
  an 
  area 
  of 
  2,000 
  square 
  feet 
  or 
  more 
  per 
  minute, 
  or 
  1 
  acre 
  in 
  from 
  

   20 
  to 
  22 
  minujes, 
  making 
  allowance 
  for 
  time 
  spent 
  in 
  moving 
  anchors 
  or 
  otherwise 
  

   adjusting 
  the 
  machinery. 
  

  

  When 
  fitted 
  for 
  work, 
  with 
  coal 
  and 
  water, 
  and 
  manned 
  with 
  three 
  men, 
  including 
  

   an 
  engineer, 
  which 
  is 
  the 
  number 
  requisite 
  to 
  operate 
  the 
  machinery 
  and 
  attend 
  to 
  

   shifting 
  the 
  anchors, 
  the 
  draft 
  of 
  the 
  scow 
  is 
  about 
  8 
  inches 
  of 
  water. 
  When 
  the 
  

   anchors 
  have 
  once 
  been 
  adj 
  nsted, 
  several 
  swaths 
  can 
  be 
  jnowed 
  before 
  they 
  require 
  to 
  

   be 
  shifted 
  over 
  toward 
  the 
  uncut 
  grass, 
  as 
  the 
  line 
  can 
  not 
  easily 
  be 
  drawn 
  so 
  taut 
  — 
  

   nor 
  does 
  it 
  need 
  to 
  be 
  — 
  as 
  not 
  to 
  allow 
  the 
  scow 
  to 
  be 
  moved 
  (pushed 
  with 
  a 
  pole) 
  

   sidewise 
  for 
  a 
  short 
  distance. 
  When 
  necessary, 
  the 
  anchors 
  are 
  shifted 
  by 
  the 
  use 
  of 
  

   a 
  small 
  boat. 
  Thus 
  the 
  scow 
  is 
  guided 
  back 
  and 
  forth 
  across 
  the 
  lot, 
  cutting 
  the 
  

   grass 
  with 
  equal 
  facility 
  in 
  both 
  the 
  forward 
  and 
  backward 
  movements. 
  When 
  the 
  

   grass 
  is 
  cut, 
  it 
  floats 
  to 
  the 
  surface 
  of 
  the 
  water 
  and 
  is 
  carried 
  away 
  by 
  the 
  current. 
  

   The 
  knives 
  are 
  set 
  in 
  motion 
  by 
  a 
  vertical 
  iron 
  shaft 
  which 
  passes 
  through 
  a 
  hori- 
  

   zontal 
  cogged 
  wheel. 
  This 
  wheel 
  is 
  geared 
  to 
  a 
  pulley 
  which 
  is 
  run 
  by 
  a 
  belt 
  from 
  

   the 
  engine. 
  The 
  vertical 
  shaft 
  is 
  so 
  arranged 
  as 
  to 
  slip 
  up 
  or 
  down 
  in 
  order 
  to 
  gauge 
  

   the 
  machine 
  to 
  any 
  depth 
  of 
  water 
  within 
  the 
  range 
  of 
  its 
  capacity. 
  The 
  extreme 
  

   depth 
  of 
  water 
  in 
  which 
  mowing 
  can 
  be 
  successfully 
  done, 
  as 
  it 
  is 
  now 
  adjusted, 
  is 
  

   about 
  8 
  feet. 
  It 
  could 
  doubtless 
  be 
  so 
  arranged 
  as 
  to 
  operate 
  in 
  deeper 
  water. 
  

  

  If 
  there 
  are 
  no 
  obstacles 
  in 
  the 
  way, 
  the 
  grass 
  can 
  be 
  cut 
  within 
  1 
  inch 
  of 
  the 
  bottom. 
  

   If 
  there 
  are 
  oysters 
  on 
  the 
  ground, 
  some 
  allowance 
  for 
  that 
  fact 
  has 
  to 
  be 
  made, 
  

   and 
  while 
  the 
  grass 
  can 
  not 
  be 
  sheared 
  so 
  close 
  to 
  the 
  bottom, 
  it 
  can 
  be 
  mowed 
  

   sufficiently 
  close 
  to 
  the 
  oysters 
  to 
  answer 
  all 
  practical 
  purposes. 
  The 
  only 
  thing 
  

   requisite 
  is 
  to 
  mow 
  it 
  short 
  enough 
  to 
  preclude 
  the 
  possibility 
  of 
  any 
  large 
  quantity 
  

   of 
  sediment 
  settling 
  in 
  it 
  and 
  choking 
  the 
  oysters. 
  This 
  object 
  is 
  easily 
  attained, 
  as 
  

   grass 
  a 
  few 
  inches 
  long 
  will 
  not 
  injure 
  the 
  oyster 
  crop. 
  It 
  is 
  when 
  its 
  length 
  is 
  

   measured 
  by 
  feet 
  and 
  it 
  is 
  filled 
  with 
  sediment 
  that 
  it 
  becomes 
  dangerous. 
  

  

  In 
  the 
  locality 
  where 
  this 
  machine 
  is 
  used 
  the 
  water 
  is 
  about 
  6 
  feet 
  deep. 
  It 
  

   has 
  been 
  customary 
  to 
  mow 
  the 
  oyster-beds 
  quite 
  frequently, 
  five 
  or 
  six 
  times, 
  

   perhaps, 
  during 
  the 
  growing 
  season, 
  from 
  the 
  first 
  of 
  May 
  to 
  the 
  last 
  of 
  October. 
  Tbe 
  

   result 
  has 
  been 
  that 
  tracts 
  of 
  bottom 
  that 
  would 
  have 
  otherwise 
  been 
  worthless 
  for 
  

   oyster-growing 
  purposes 
  have 
  been 
  converted 
  into 
  beds 
  as 
  productive 
  as 
  any 
  in 
  the 
  

   river. 
  The 
  coat 
  of 
  building 
  a 
  similar 
  machine 
  is 
  estimated 
  by 
  Mr. 
  Allen 
  to 
  be 
  from 
  

   $450 
  to 
  $500.* 
  

  

  HaD, 
  Ansley, 
  Kept. 
  U. 
  S. 
  Fish 
  Commission 
  1892, 
  pp. 
  477 
  and 
  478. 
  

  

  