Bourbon - Offshore - Surf - SMS manual 2016

Previous Page

Next Page

Page Background

A

nc

h

or

H

andlin

g

and To

w

in

g

O

p

erations

P

rocedure

BOS-

P

RD-2

6

.900

6

14

F

orces

at

the

anchor

can be

ca

l

cu

l

ated us

i

ng

the

formu

l

ae be

l

ow

LF

=

B

P

/

cos

(

arcs

i

n

(WD

/

WL))

and

U

L

=

B

P

x

tan

(

arcs

i

n

(WD

/

WL))

where

LF

=

Li

ne

force

i

n wor

k

w

i

re

;

U

L

= Up

li

ft

force at anchor

;

B

P =

B

o

ll

ard Pu

ll

be

i

ng exerted

;

WD

=

W

ater

D

epth

;

WL

=

Wi

re

L

ength

dep

l

oyed

,

measured

from

S

tern

R

o

ll

er

.

T

he best pract

i

ce

i

s

therefore

to

f

i

nd

the

opt

i

mum

pu

ll

pos

i

t

i

on

and

avo

i

d over

l

oad

i

ng

the

e

q

u

i

pment

wh

i

ch

wou

l

d

resu

l

t

i

n

an

unsafe

s

i

tuat

i

on

. I

f

prob

l

ems

are

exper

i

enced

i

n

brea

ki

ng

out the

anchor cons

i

derat

i

on

should

be

g

i

ven

to

us

i

ng

another

vesse

l

to

ass

i

st

,

but

any

such

ass

i

stance

should

be

fu

ll

y

r

i

s

k

assessed pr

i

or

to

commencement of

operat

i

ons

.

I

f

brea

ki

ng

out

does

not

occur

after

a

per

i

od

of

approx

.

3

0

m

i

nutes

,

the

forces

on

the

w

i

nch

should

be

i

ncreased

s

li

ght

l

y

.

T

he

r

i

g

can he

l

p and

speed

-

up

the

operat

i

on

by hau

li

ng

the

anchor

li

ne

at

the

same

t

i

me

!

W

hen

the

r

i

g

conf

i

rms

that

the

sh

i

p

can

start

to

brea

k

out

the

anchor

,

the

li

ft

i

ng

operat

i

on

can

start

.

Wi

th

the

r

i

gs

approva

l,

br

i

ng

the

ahead

power

up

to

around

3

0

to

5

0 %,

the w

i

nch

operator

on

the

r

i

g

shall

report

any

change

i

n

the

tens

i

on

to

the

vesse

l,

th

i

s

w

ill i

nd

i

cate

when

the

anchor

has

bro

k

en out

.

T

he

d

i

stance

from

the

r

i

g

and

the

var

i

at

i

on

of

the

tens

i

on

of

the

r

i

g

’

s w

i

nch

i

nd

i

cate whether

or

not

the anchor

has

bro

k

en out

.

T

he

vesse

l

has

to

start

hau

li

ng

on

the wor

k

w

i

re

.

W

hen

i

t

’

s

conf

i

rmed that

the

anchor

has

bro

k

en

out

,

the

r

i

g

w

ill

s

l

ac

k

down

the

anchor

li

ne

tens

i

on

.

After

brea

ki

ng out

,

the

thrust

should

be ma

i

nta

i

ned

.

W

hen

the

anchor

i

s

l

oose

from

the

bottom

,

the

sh

i

p

i

nforms

the

r

i

g

and

cont

i

nues

to

heave

up

the

anchor

. N

orma

l

p

i

tch

forward w

ill

be

3

0

to

5

0%,

th

i

s

to

avo

i

d

the

anchor

s

li

pp

i

ng

through

the

chaser

co

ll

ar

.

O

nce

the

r

i

g

has

s

l

ac

k

ed

down

the

cha

i

n

tens

i

on

,

w

i

nd

i

n

on

the w

i

nch

,

unt

il

the

anchor

i

s

under

the

stern

ro

ll

er

. R

educe

ahead

power

,

and

the

r

i

g w

ill

w

i

nd

i

n

cha

i

n

. N

orma

ll

y

the we

i

ght

of

the

cha

i

n

w

ill

stop

the

anchor

fa

lli

ng

out

of

the

co

ll

ar

,

but

some

power

ahead

he

l

ps

k

eep

i

ng

the

vesse

l

on

the

correct

li

ne

.

Vers

i

on

SF(BOS-

P

RD-0

7

01.000

5

-

ver

.

C

R). O

r

i

g

i

na

l D

ate

:

3

1

/

12

/

201

5

.

Vers

i

on

D

ate

: N

/A

.

Va

li

d

vers

i

on

on

l

y on QM

S

s

i

te

.

Page

26

of

60

Procedure prepared by

: BOS

Head

of

O

perat

i

ons

.

Approved

by

: BOS

Head

of

O

perat

i

ons

.

Va

li

dated by

: BOS

Qua

li

ty

R

epresentat

i

ve

.

602