FOUNDATION DESIGN FOR

FOUNDATION DESIGN FOR

30MT WORKING LOAD WINCH SYSTEM

TABLE OF CONTENTS

SECTIONS

1 Introduction & Summary

2 Loading & Assumption

3 Aft Mooring Winch System Tie-down Design

3.1 Aft Mooring Winch Tie-down

3.2 Anchor Fairleader Tie-down

Fwd Mooring Winch System Tie-down Design

4.1 Fwd Mooring Winch Foundation

4.2 Fwd Mooring Winch Tie-down

Appendix

A. Typical Vessel Structure Member Properties 17

B. Drawings 25

1. Aft Mooring Winch System Tie-down & Details

2. Fwd Mooring Winch System Tie-down & Details

Section 1

Introduction & Summary

1.1 INTRODUCTION -This mooring winch system's foundation & tie-down design for support vessel " Sietas Yard Type 161-A / 161-B " is performed on the behalf of our Client, TSPL, in order to ensure that the proposed mooring system of support vessel " Sietas Yard Type 161-A / 161-B " is capable of operating with its braking load of 4OMT offshore.

The proposed winch system consists of 2 Fwd winches & 2 aft winches. The 4 nos. winches are identical and are designed for 30MT maximum pulling load with 38mm wire ropes. The Fwd winches will be located on forecastle deck portside & starboard side symmetrically

from frame 97 - 101,600mm from the winch base to deckhouse bulkhead. The mooring line will run through the multi-rollers fairleader, which is seated on the existing double bitts bollard base about 7.5m in front of mooring winch.

The aft winches will be located on shelter deck portside & starboard side symmetrically from

frame 19 - 22, 1400mm from sideshell to winch base. The mooring line will run astern

through anchor fairleader then through multi-roller fairleader (about 45 outboard). The

anchor fairleader is located over one transverse bulkhead (about 2 feet Fwd of frame 2) & 2 nos. deck longitudinals. The multi-rollers fairleader is to replace existing panama chock.

The mooring lines will be in tension to a maximum of 40MT of environmental forces, and the braking capacity of the winch is 40MT, a dynamic factor 1.5 to be considered when designing the winches foundation & seafastenings.

The scope of work (this report) is therefore as follows: Design Fwd winches' foundation on forecastle deck Tie-down design for winches base (Fwd & aft winches) - Tiedown design for anchor fairleader (stem)

Vessel strength check at winches location and anchor fairleader

We visited the support vessel "Sietas Yard Type 161-A / 161-B" which was berthed in XX Shipyard, Location on XX. During the time we were on board, we discussed

the followings:

multi-roller fairleader orientation and location to prevent chafing of wire rope and their reinforcement anchor fairleader to be within 5 of fleet angle

- reviewed the submitted report (HER-001-001, Rev. A, dated on 20/06/04). The report uses 30MT to design the winches seafasteninglfoundation and use "I" beams for winches foundation on "uneven" deck of the forecastle deck. The original "I" beam is modified to "T" beam to suit the "uneven" deck at the forecastle deck

1.2 RESULTS OF ANALYSIS -

The analysis is to comply with code of API & AISC. No 1/3 increase of allowable stress will be used in the analysis. Results show that the proposed tie-down for mooring winch & anchor fairleader is adequate to maintain them safely on the deck. The existing shelter deck & proposed foundation on forecastle deck is adequate to support the winch & anchor fairleader

during the offshore operation.

Section 2

Loading & Assumption

2.1 LOADING & ASSUMPTION -

The proposed winches are identical (only symmetrical about portside & starboard). The maximum

pulling force is 30MT. The braking load is 40MT. The overall dimension for winch is 2200mm(L) x 2900mm (B) x 1600mm (H)Specification:

Line Pull:

30MT @ l* layer wire

22.36MT @ 2nd layer wire

20.23MT @ 3rd layer wire

18.48MT 4~ layer wire @17MT @ 5 layer wire

Line speed:

9 mlmin @ 38 gpm (inner layer)

Rope capacity: 500 metres @ $38mm Rope

Working Pressure: 2600 psi

HP Required:

75 HP / 440V / 6OHz / IP65

Weight:

5MT (without wire rope) 8MT (with wire rope)

The first layer wire distance to bottom of winch base is - 1160mm.

The original design of "I" beam for winch base is 200UC x 59.5kglm. The distance between two "I" beam of winch base be 2200-205 = 1995mm in longitudinal direction.

Section 3

Aft Mooring Winch System Tie-down Design

25MT Working Load Winch Tie-down Analysis on Vessel

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