Chain length in a rope rode

[Rum_Pirate]

I have a 22' Mako T-top centre console with twin 85hp outboards.

Currently (when not on the hard) moored in 5'0" of water with a mainly sandy bottom, seaweed beds and a few small stones.

Using two Fortress anchors. One has 1/2" dia three strand nylon rope with 3/16" chain, then other is 5/8" dia three strand nylon rope with 1/4" chain.

Using 10'0" lengths of stainless steel chain.

Some say 6'0", while some say a boat length's worth of chain is best.

What (size and) length of chain should ideally be used in the rope rode?

 

[Davy_S]

I would use 10metres of 6mm chain and the rest 12mm rope.

 

[BruceK]

The correct answer to that I believe is enough chain weight too keep the anchor shaft down when under expected pulling tension. The pragmatic answer is about a boat length of it. The chain weight therefore needs to be matched to the boat weight. How heavy is your boat?

 

[Rum_Pirate]

The correct answer to that I believe is enough chain weight too keep the anchor shaft down when under expected pulling tension. The pragmatic answer is about a boat length of it. The chain weight therefore needs to be matched to the boat weight. How heavy is your boat?

Boat 23’0” dry weight 2,000 lbs + engines (2x265) 530 lbs + fuel say 200 lbs + miscellaneous so around 2,800 - 3,000 lbs.

 

[BruceK]

So ~1300kg.

I'd go with a minimum of 7mm / 9/32 Grade 40 DIN766 preferably 8 or 8,3mm / 5/16th