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Karver Winches - A Truly Unique Proposition

by Phil Anniss 25 Mar 10:01 PDT
Karver Winches - A Truly Unique Proposition © Jean-Marie Liot

Karver are relatively new to the world of sailboat winches but they are bringing something completely different to the market. Their KSW Speed and KPW Power winch ranges may not suit every application but, by being totally unique, if you fall in their sweet spot they can offer some dramatic advantages.

In 2018 Karver took over a Brittany (France) based manufacturer, Pontos Winches, and in spring 2019 launched a fully updated range. The key difference is that these self-tailing, manual winches have four automatic gears that utilise epicyclic gear trains and automatic load detection. There are just three sizes (40, 46 and 52), but by being clever with the gear ratios they have created two distinct ranges orientated to either SPEED or POWER.

The four gears are, in effect, two sets of two gears with a physical load sensor in the drum responsible for switching between gears 1&2 to 3&4. The user simply changes winding direction to seamlessly switch gears WITHOUT the need for any switch or button.

The table below shows two market leading, self-tailing, size 40 winches from Harken and Andersen and compares them to a Karver KSW Speed 40 and the KPW Power alternative.

Harken Radial 40Andersen 40Karver KSW 40 SpeedKarver KPW 110 (40) POWER
Speeds / Gears2244
Drum Base Ø (mm)157152171171
Drum Ø (mm)80758484
Height (mm)175172189189
Weight (g)3800490057005500
SWL (kg)850N/A8501000
Maximum Line Ø (mm)12141212
Gear / Power Ratio 12.1 / 13.51.3 / 8.90.4 / 2.31.9 / 11.6
Gear / Power Ratio 26.3 / 39.96.0 / 40.01.3 / 8.05.4 / 32.7
Gear / Power Ratio 3  1.9 / 11.66.6 / 40.0
Gear / Power Ratio 4  6.6 / 40.018.7 / 112.9

The Harken / Andersen winches are representative of most other winches available on the market. They have similar drum base diameters and heights. The drum diameter is smaller on the Andersen winch which means there is less line on the drum. This translates to slower lines speeds (for a given gear ratio) and to achieve the same grip requires extra turns on the winch.

By comparison, in terms of physical appearance the Karver winches have a bigger base diameter and are taller / heavier, which is due to the increased space/weight required for the extra gears and automatic load detection system. The drum diameter is also bigger which provides greater line speed and improved grip, which comes into play for both the Speed and Power ranges.

However, it is the gear/power ratios which provide the really striking difference between the Karver Speed/Power winches and the rest of the competition. In very simplistic terms:

  • Power ratio is the increase in the force being applied to the line - This is a function of gear ratio, drum diameter and winch handle length.
  • Gear ratio is the number of turns of the handle to one turn of the winch drum

KPW Power

The industry standard for naming winches (e.g. "Size 40") is derived from the maximum power ratio. But this is where the Karver KPW Power totally rocks the boat! You can see that gear/power ratios 1 & 3 of the KPW are very similar to the Harken / Andersen winches but then gear 4 delivers almost three times more power than the other two, which is why it is called a Size 110.

However, this winch is really still only a size 40 winch by every other measure. The KPW Power is designed for the same line diameters and overall SWL to a standard size 40 winch, but it is coming from a completely different perspective. This winch is not designed to exert any more power on the line, it is designed to exert the same amount of power with a "fraction of the effort" required with other winches.

But what can you use all this effortless power for? KPW winches can be used as coach roof winches where you are constantly fine-tuning headsail and main halyard tensions. It makes it very easy to make small incremental adjustments at high load.

However, the main application Karver see for this winch is as a primary genoa winch. The first gear is similar to other winches but then there is an easy, smooth transition through gears 2, 3 and 4 as the load on the sheet increases and then getting the final six inches of trim on your overlapping genoa becomes a breeze!

The KPW Power range is being marketed as a bridge / stepping-stone between standard manual and electric winches. Many people switch to electric winches to reduce the effort required to manage their sail plan but the Karver KPW could achieve the same objective for a significantly lower cost than electrification.

KSW Speed

The KSW Speed range is aimed at a completely different user. As you can see from the above table, this is a true size 40 winch, with maximum power ratio of 40:1. The top two gears are similar to a standard race winch, but gears 1&2 are all about line speed. In gear one a 0.4 rotation of the winch handles equals a single drum revolution. This is a completely different proposition to most winches which have a first gear requiring 1.5 - 2 turns of the handle for every drum revolution. This winch is aimed specifically at race boats with muscular crew, to increase the speed and efficiency of tacking / gybing manoeuvres.


The Karver KSW Speed and KPW Power winch ranges are unique. The KSW Speed range is going to be suitable for a very narrow group of serious race boats, however the KPW Power range offers significant benefits for quite a wide range of sailors on 30-45ft boats. They are suitable for short-handed sailing, an ageing crew, and an alternative to switching to electric winches.

You can view Karver's range of KSW and KPW winches, or, if you have any questions or would like to talk about upgrading your winches, you can contact or via the Winch Enquiry Form.

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