Mooring Sizes

[Guest]

Anyone know of a source of information on mooring sizes. Ground tackle weights, riser sizes etc. Boat is 28' 4 ton yacht. I have had a lot of duff jobs done recently so am planning to do it myself this year.

<hr width=100% size=1>

 

[Trevor_swfyc]

Hi AKM,

Just spotted your post, as you are considering do it yourself can you confirm this is a drying mooring we are considering?. As I would not entertain do it yourself otherwise.

Trevor
Moorings Officer
SWFYC

<hr width=100% size=1>

 

[LadyInBed]

Re: DIY

Why not? There are several ways of putting a non-drying mooring down.

<hr width=100% size=1>

 

[Trevor_swfyc]

Re: DIY

Nigel,

Pleased to hear them!

Regards Trevor

<hr width=100% size=1>

 

[LadyInBed]

Re: DIY

Wheel out to knee depth at LW, under sling on 1 or 2 inflatables, wheel out till rollers can be knocked out, wait for lift off, tow/motor out to position, cut sling line.

Secure onto a tray on top of an inflatable at LW, wait for lift off, tow out to position, release securing lines, deflate one of the tubes.

This requires scubies - Wheel out as far as possible at LW with lifting bag and tow line attached, inflate lifting bag, wait for lift off, tow out to position, scubies control lifting bag decent.

The first two methods are ok if you are not too picky as to how the mooring block lands, but any local scubies would check things out as a training exercise, or for a suitable donation, and if necessary put a lifting bag on the mooring chain to right the block.


<hr width=100% size=1>

 

[jleaworthy]

Your mooring requirements will depend upon the size, displacement and type of boat; the mooring location, exposed or sheltered; type of seabed; maximum depth and tidal range. Gael Force (Tel 0146322942) sell made up kits for permanent moorings and will advise on what you need for your own situation. A chat with them will cost you nothing. Their kits are packed on a single pallet and use two anchors rather than a heavy weight. Having laid concrete blocks myself I know how fraught the operation can be, sometimes downright dangerous, unless meticulously planned and executed.

<hr width=100% size=1>

 

[Guest]

Thanks for the contact. What I am looking for is an authoratative source of information. Are there any standards for a given set of conditions BS,LLoyds, DNV, DIN, EN etc. This should enable me to check the practicality of a DIY job, I have access to workboat and diver or at least to check the spec offered by a subcontractor. Has this topic ever been covered in a magazine article. I have tried web searches but not managed to find anything.

<hr width=100% size=1>

 

[Guest]

Re: DIY

Sounds interesting. Have you tried it. What sort of weight would be practicable with two inflatables.

<hr width=100% size=1>

 

[LadyInBed]

Re: DIY

Being a diver I tend towards using a lifting bag and tow because of the control that you have when placing the block.

<What sort of weight would be practicable with two inflatables>
The short answer is – A lot more than you can handle. Given that a single 3mtr inflatable has a payload of around 450 to 550 Kg’s.

The crucial thing is load spreading, you need an H frame or better a (digital)8 frame. The sides of the frame lay just outside the centre line of each boat.

The shape of the Mooring block dictates how easy it is to move around. Flat round ones role, other shapes may have to be attached to the frame and manoeuvred by lifting the frame.


<hr width=100% size=1>

 

[vyv_cox]

As others have said, a lot depends on the location. Accepted practice in one area may be completely inappropriate in another.

A guideline from my experience. My first boat had very similar dimensions to yours. In an exposed, very strongly tidal location, this was the gear I had laid for me by a professional outfit. It is probably somewhat over the top because I had exactly the same gear on a 34 ft 6 ton boat later. It's worth remembering that the weight/displacement actually does not have too much influence.

2 x Admiralty pattern anchors, weigh 1 hundredweight each. Ground chain 3/4 inch, I think 60 ft in length. Anchors are laid up/down tide. Riser 3/4 inch to the buoy, but for your boat 1/2 inch would be acceptable. Length dependent upon tidal range and amount of swinging room, but only a couple of metres more than the calculated maximum is required with this arrangement. Pick-up chain 1/2 inch galvanised. Swivel in the riser a few metres up from the join link to the ground chain. All links welded.

<hr width=100% size=1>