What size of chain riser ?

[Swg]

I've got a 1tn 20ft sailing boat on a slightly exposed swing mooring. I need to fit a riser from the very heavy ground chain to the mooring buoy. What size chain should I use?

 

[VicS]

5/16" minimum. In an exposed location 3/8"

I think mine is 3/8" ( 19ft boat) but the mooring is suitable for a boat somewhat larger.

Be sure what you get will fit the stem head fittiing. Mine only just does so.

 

[Swg]

Vic, it's the chain from the heavy mooring buoy to the sea bed rather than boat to buoy.

 

[VicS]

Vic, it's the chain from the heavy mooring buoy to the sea bed rather than boat to buoy.

Sorry did not read that properly. Ours have always been all one length, from the heavy chain cast into the sinker right onto the boat.

Can go heavier then 1/2". The limit is what weight the buoy can take.

 

[webcraft]

.
The thickness should be governed by how long it takes to rust through rather than the weight of the boat. Even with galvanised chain on a tidal mooring the galvanising soom wears off where the chain comes on and off the bottom.

19mm non-galvanised lasts three years with us before I replace it. By then the thinnest bit is down to around 8mm, while the bit that is constantly immersed but not subject to wave action or mudscraping is virtually untouched.

So really the thickness depends on what the buoy will support and/or how often you want to replace it.

- W

 

[William_H]

Chain size

This depends primarily on what you can find second hand at the right price. Heavier the better provided the buoy can support it. As said the actual strength is not in question just the wear life of the chain. olewill

 

[vyv_cox]

On Menai Strait, which is about as exposed a mooring as you would want, I believe it is the case that the mooring contractors do not recommend anything less than 3/4 inch for risers for any boat. Some of the drying moorings inshore may use less, laid by the owners.

I remember being show a chain on which a small mobo had been moored all winter at the north of the Strait. New at the beginning of the season, almost all links were worn to less than half original thickness.

 

[sailorman]

On Menai Strait, which is about as exposed a mooring as you would want, I believe it is the case that the mooring contractors do not recommend anything less than 3/4 inch for risers for any boat. Some of the drying moorings inshore may use less, laid by the owners.

I remember being show a chain on which a small mobo had been moored all winter at the north of the Strait. New at the beginning of the season, almost all links were worn to less than half original thickness.

3/4" chain riser on a 20 footer

 

[lw395]

You can make the part of the riser that never touches the bottom lighter.
The worst wear is the bit that swirls around in the mud/on the rocks, how fast that wears depends on conditions, not on boat size. Obviously how much metal you need remaining depends on boat size.
I think in Portsmouth Harbour we used 3/4 inch and it was OK after 3 years.
Some small boat moorings are about 9 mm chain, and get lifted at the end of a short season.

 

[vyv_cox]

3/4" chain riser on a 20 footer

I believe so. If you had seen the Strait in a good southwesterly against a four knot tide you would be pleased to have that much. Tidal range is somewhere around 8 metres, so plenty of potential for wear at the lower end. The chain is hanging from the buoy, of course, and the pickup line would be far lighter. I used exactly the same mooring, first for a light 27 footer, then a 29, then a 34.

 

[Swg]

Thanks all. This forum's great when you get definitive answers from people with similar experience. I'll get3/4 inch chain and lift at the end of the season to help it last. Any Recvpmendatopns on supplier or indications of price?

 

[VicS]

Thanks all. This forum's great when you get definitive answers from people with similar experience. I'll get3/4 inch chain and lift at the end of the season to help it last. Any Recvpmendatopns on supplier or indications of price?

cannot recommend any particular supplier but that is going to be heavy. Around 75 to 80 kg per 10m

OTT on a 20ft boat and handling it will not be a DIY job unless you are exceptionally strong

 

[vyv_cox]

Thanks all. This forum's great when you get definitive answers from people with similar experience. I'll get3/4 inch chain and lift at the end of the season to help it last. Any Recvpmendatopns on supplier or indications of price?

Your profile doesn't say where you are, so it is difficult to suggest anyone. My last mooring chain came from Chester Chain, who bought used lock gate chain from Manchester Ship Canal. That was years ago, so don't know if they still do it (or even if they still exist!)

 

[philip_stevens]

I've got a 1tn 20ft sailing boat on a slightly exposed swing mooring. I need to fit a riser from the very heavy ground chain to the mooring buoy. What size chain should I use?

The attached shows the recommendation that boat owners used to get from Truro Harbour Office for moorings in the river Fal - this includes from Truro to Mylor. Below Mylor "belongs" to Falmouth.

It would help with answers, if members knew your home or mooring location, re:chain suppliers.

 

[CreakyDecks]

I just put a mooring down for a similar sized boat (on a drying mooring). I used 3/4" for the ground chain and 1/2" for the riser. Don't underestimate how much heavier and difficult to handle the bigger chain is! Once it started going over the side of my dinghy there was no way I was going to stop it.