No items in cart

Knowledge Base

Rode Length / Scope

You can have the ultimate anchor but if you don't give it enough chain length- It will be USELESS.

The ratio of the rode length to water depth is known as the scope. Anchoring with sufficient scope brings the direction of strain close to parallel with the seabed. In general the longer your rode is the better. 10:1 Scope is preferable in windy conditions. It’s recommended that an average cruising boat carries at least 300 feet of rode, which will allow for 10:1 scope in 25 feet of water (5 feet allotted for free-board height). This will ensure that most of the time you can anchor with 10:1 Scope.
It is generally accepted that in a storm situation we strive to put out 10:1 scope, but why? See the table below to understand the effects of scope on your holding power.
Many cruisers find that 8:1 scope is a nice compromise between rode length and maximum anchors holding power.


A line/rope is subject to degradation with time from chafe and UV exposure. Further, this damage is not easily identified nor can be easily quantified.

We recommend using a chain only if possible.

When you have to use a rope it should be in a visible location where you can see it, preferably only with bridle or snubber.

 

Here is a table showing the importance of the scope and how it affects your anchor holding power.

 
Scope % Maximum anchor Holding Power Deg
2;1 10 % 30
3:1 40% 19.5
4:1 55% 14
6:1 70% 9.5
8:1 80% 7
10:1 85% 5
20:1 89% 2.8

 

Try to use a long chain if possible. No need for more than 10:1 scope. A long chain with a good anchor will do the job.

Search