Probably not.
A kellet is a dead weight hung on the rode, often used in the belief that it improves anchor holding. With an adequately sized modern anchor, it makes little practical difference once conditions become demanding.
There is one job a kellet does well: reducing your swinging circle in light conditions.
What a kellet is
A kellet, also known as a sentinel, angel, chum, or buddy, is any dead weight attached to the rode. It can be a loop of chain, a bundled length of heavy chain, a secondary anchor, or a purpose-built kellet.
Where you place it depends on what you want it to do, so a kellet cannot do all of the following at once.
Minimizing your swinging circle
This is the most useful application, and it applies only in light to moderate conditions. A kellet stops the boat wandering around the anchor in calm weather and reduces its swinging circle in light winds.
Position it down the rode from the boat by roughly the vertical distance to the seabed: water depth plus the height of the bow roller above the water.
Whether you need one is another question. In an open anchorage, swinging room usually isn’t a concern. In a confined one, adjusting the amount of rode deployed may be more appropriate. A kellet earns its place where different types of boats respond differently to wind and current, and you want to reduce movement in light airs.
Lowering the angle of pull
A lower angle of pull on the anchor improves holding performance. A kellet has limited ability to achieve it.
As load on the rode increases, the kellet is lifted and the rode becomes progressively straighter. In the conditions where the anchor is most likely to be challenged, the effect is small. Once the rode is straight, there is none.
For the greatest effect on pull angle, place the kellet relatively close to the anchor, but not so close that it simply rests on the seabed.
Shock absorption
For the greatest effect, position the kellet roughly halfway between the anchor and the bow. This balances the distance the kellet can move against the leverage gained by positioning it farther down the rode.
We don’t recommend relying on a kellet for this. As loads increase, its ability to absorb shock disappears when you need it most. Use rope or a dedicated snubber instead, which give more predictable elasticity.
Buoys
A buoy attached to the rode works in the opposite way to a kellet. Instead of lifting a weight as the rode straightens, the rode must pull a float downward. The force comes from buoyancy rather than weight, so a buoy is lighter to store aboard.
For shock absorption, position it roughly halfway between the anchor and the boat. Its effect decreases the same way, as load increases and the rode straightens. A buoy also raises part of the rode initially, which increases the angle of pull on the anchor, though under higher loads it is pulled down and the effect becomes small.
A buoy can also help keep the rode clear of tall seabed obstacles such as coral or dead trees. Place it slightly farther from the anchor than the water depth. In light conditions it holds the final section of rode above the seabed, while heavier loads pull it down and restore the available scope.
What to do instead
Start with the anchor. A modern design will generally outperform an older design of similar weight, and increasing anchor size provides a direct improvement in holding capacity.
If reducing your swinging circle is the priority, look at your anchor size, available scope, and anchorage conditions before adding another component to the rode.
For most boats with a correctly sized modern anchor and a properly configured rode, a kellet adds complexity without providing much benefit.
Further reading
More on this topic can be found on Peter Smith’s personal website: Anchor Rode Kellets – Uses, Misuses, and Misconceptions.