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S&S Swan General - Chain locker
04 February 2018 - 15:12
#22
Join Date: 02 January 2008
Posts: 1547

Peter

The chain box inside dimensions for 3/8" chain is 12-3/8" square, and it needs to be measured if there is sufficient height in the fore peak. 
Check where the mentioned box dimension hits the stem when measured horizontally forward from the bulkhead, this is the base point for the height of the box assuming it is located right aft. The chain pipe lower end needs to be at least 39" above the base, with 15" of free fall. 
Scaled off the drawings there may not be enough height, then you have the choice of storing part of the chain outside the box in the fore peak, or going to Jan's approach. The height requirement goes down one inch for each 7.6 ft reduction of chain length stowed in the box.
Kind regards
Lars

05 February 2018 - 01:35
#23
Join Date: 31 July 2007
Posts: 88

Thank you  Lars! I'll  do the measuring  as soon  as  the rain stops  

Peter  

04 March 2018 - 19:20
#24
Join Date: 31 July 2007
Posts: 88

Attached pictures tell the story: in the first picture the chain piles up as it is brought in and forms a chain castle. When it falls over at sea it may cause jamming when the chain is brought out. In the second picture I placed a container 12 inches diameter. The chain still piles up and spills over. The third picture looks into the container from the top and shows that it spilled over before it was filled at the bottom. What am I doing wrong? Or is it just the perverse behaviour of inanimate objects?

05 March 2018 - 18:31
#25
Join Date: 02 January 2008
Posts: 1547

Peter

Thank you for the photos

It appears that the container is not vertically below the chain pipe. Would it be possible to temporarily lead the chain to a point where it drops vertically towards the center of the upright container bottom? Then you would see if the chain distributes itself evenly.
The calculated stowed volume of your chain is 2.12 cu.ft. how does this agree ?
Lars

08 May 2018 - 20:04
#26
Join Date: 01 April 2007
Posts: 106

Dear Professor/Lars,

As you know I would like to install an anchorwinch. The positon should be just before the bulkhead in the fore peak. Is the deck in that area sandwich or full laminate ? Do I need a backing plate for the bolts of the anchor winch ?

Best regards,

Jan

09 May 2018 - 07:30
#27
Join Date: 02 January 2008
Posts: 1547

Dear Jan

The deck is sandwich, and you can verify this by looking at the underside of the deck inside the fore peak - a smooth underside means there is sandwich. Even if there are local recesses showing solid areas, the windlass attachment is likely to be in the sandwich area.
 
The deck foam core can not resist the compression forces from the windlass attachment bolts, and solid inserts are necessary at the bolts.
 
A backing plate is recommended below deck, although only its aft part is effective, the forward end of the windlass is pushed down when it is pulling.
 
It is good practice to remove the teak deck under the windlass, and install a support plate slightly thicker than the teak, and bigger than the windlass footprint.
The inserts and support plates could be of G10 FRP sheet.
 
If you would like to get more  detailed information, the specification for your chosen windlass is required.
Kind regards
Lars

15 May 2018 - 19:22
#28
Join Date: 01 April 2007
Posts: 106

Dear Lars,

Thank you for your instructions. I have constructed a supportplate made of solid teak. And I will make a backing plate as well. The holes will be inserted with epoxy after removing approximately 1 cm of the core around the hole. Is that sufficient ?

Please see attached photo's for details of the winch (maxwell RC10-8) and support plate.

Kind regards,

Jan

16 May 2018 - 09:25
#29
Join Date: 02 January 2008
Posts: 1547

Dear Jan

Thank you for the photos.
If the deck is compressed by the bolts, the recommendation for the epoxy ring outer diameter is 4 times bolt diameter with a standard epoxy, having approx 70 MPa compression strength. There are epoxies formulated for higher compression if you prefer that.
The chain pipe hole sees no bolt compression, but has to resist shear, and here your suggested 1 cm epoxy ring width would be fine.
Kind regards
Lars

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