Calculating the weight of a boat anchor: easy method
→ Boat anchor: find the ideal weight
Forget your old scales, today the weight of a boat anchor is calculated in relation to the length of your boat. In fact, it's one of the main parameters to take into account before placing an order!
To know how to choose your boat anchor, you'll need to consider the type of anchorage, the nature of the seabed and, here again, the length of the boat.
Boat anchors are a piece of boat equipment used to stabilize a vessel at sea in the place where you wish to anchor. A boat anchor can therefore be used to immobilize a boat on all rocky, muddy and sandy seabeds.
Depending on the anchor you choose, you can use either temporary or permanent anchors.
It's important to note that the choice of boat anchor depends on the nature of the seabed and the length of the boat. The weight of your boat anchor will ensure a safe and comfortable mooring.
→ Which anchor for my boat?
The evolution of manufacturing processes now means that the volume of an anchor is no longer essential in choosing the right model. The alloy and shape of the boat anchor are criteria to be taken into account.
That's why you'll find different types of boat anchor available on the market. It's important to differentiate between them according to boat type (and weight), sailing program and budget. Once you've identified your intended use and anchorage area , you need to select the right type of boat anchor.
To be effective, an anchor doesn't have to be heavy, but rather adapted to the seabed and the length of the boat.
→ Nature of the seabed and type of anchoring
At sea, a successful anchorage allows you to keep your boat stationary thanks to an anchor, and to remain stable in all situations. Boat anchors are a real safety feature, enabling you to sail with complete peace of mind.
Good anchoring requires the use of a good anchor and the choice of a boat anchor adapted to various elements such as the type of bottom, the weight of the anchor, the length of the boat, and so on.
Choosing the right anchor for the type of sailing you do and the type of boat you own is very important. There are many different types of boat anchors on the market, all perfectly suited to your needs.
Below is a list of boat anchors suitable for different types of mooring and seabeds:
➡️ Classic anchor = Plow anchor
➡️ Occasional anchoring = Flat anchor
➡️ Sand = Leg anchor
➡️ Sediment = Flat anchor
➡️ Gravel & Seaweed = Ploughshare anchor
How to choose a boat anchor: regulations and advice
It's important to remember that there's no such thing as a universal boat anchor. The most suitable anchor always depends on the type of boat and the nature of the seabed on which you are anchoring. To help you in your choice, try to define the type of seabed where you anchor most often.
If you sail in waters where the nature of the bottom may differ from one anchorage to the next, you'll need to consider purchasing an additional . Having one or two boat anchors on board helps to ensure anchoring in good conditions.
As detailed above, your choice of boat anchor depends essentially on the size of your boat. Choosing the right anchor weight in relation to the boat is a decisive factor in learning to sail, and will help you avoid an uncomfortable anchorage.
→ Flat anchors
The flat anchor is used for occasional anchoring and performs well on rather sandy and muddy bottoms. This anchor is fitted with remote legs and is lighter.
The flat anchor has excellent holding power thanks to its legs, and is very easy to use, with a chain length averaging 3 times the height of the water under the boat.
Despite its good holding power, it has a tendency to unhook and its two points rarely hook together. Consequently, this type of anchor is not recommended on rocks or seaweed.
✅ Very high holding power on sandy bottoms, attractive price
❌ Not very versatile, sometimes unstable, may stall.
→ Plow anchors
The plow anchor is used for classic or emergency anchoring and is very effective on all types of soil (soft, rock, seaweed...). This has an important advantage: it can be easily replaced if it becomes unhooked.
In fact, thanks to its unique design, the plough anchor locks perfectly into the mud or sand. They are particularly long, and are generally hauled in using a bow roller.
Finally, there are several models of plow anchor: CQR, Kobra, Rock, Delta. The latter can feature specific characteristics such as an articulated rod.
✅ Performs well on all types of bottom, won't stall
❌ Voluminous, high price
→ Grapple anchors
Grapple anchors are mainly used as anchors for fishing dinghies.
Highly effective on seaweed-covered bottoms, grappling anchors are not designed for conventional anchoring and are very practical for finding a mooring line.
✅ Space-saving, lightweight, quick to set up
❌ Low holding power
→ Floating anchors
A is not really considered a conventional anchor, but rather a safety device. It is used to stabilize a boat in bad weather or when anchoring is uncertain.
You can also which may prove very useful on board, for both fishing and pleasure boating.
✅ Lightweight, space-saving, quick to install
❌ Less effective on larger boats
→ Calculate anchor weight according to boat
The weight of a boat anchor is a crucial element when it comes to anchoring. The anchor weight depends on the boat and a number of other factors, such as the boat's length, the height of the water, the nature of the seabed and the desired hold. It's important to understand that the weight of an anchor in relation to the boat must be adapted to ensure a good hold.
The choice of anchor weight in relation to the boat must take all these factors into account to ensure a safe and secure hold in all anchoring conditions. Never underestimate the importance of an anchor's weight in relation to the boat, as this can have dramatic consequences if the wrong choice is made.
To calculate the weight of a boat anchor, we recommend you refer to the table below:
→ Anchor and boat length
Calculating the weight of a boat anchor is the essential indicator to consider when purchasing a marine anchor.
As shown in our table, for boats up to 4 meters, the recommended weight of an anchor in relation to the boat is 3.5 kg. For 5.5-meter boats, the weight of an anchor in relation to the boat is 6 kg, and for 6.5-meter boats, the weight of an anchor in relation to the boat is 8 kg.
For larger boats, from 16 meters upwards, the weight of an anchor in relation to the boat is 20 kg. For boats over 25 meters, the recommended weight of an anchor in relation to the boat is 60 kg.
As mentioned above, there are different types of anchor, such as or knuckle anchors, ploughshare anchors, jas anchors... Each type of anchor has a specific recommended weight, depending on the size of the boat.
To remember: weight of an anchor in relation to the boat (most common dimensions) :
▪️ Anchor for 6.50 m boat: recommended weight = 8 kg
▪️ Anchor for 7.85 m boats: recommended weight = 10 kg
▪️ Anchor for 9 m boats: recommended weight = 12 kg
▪️ Anchor for 16 m boat: recommended weight = 20 kg
→ Anchor cables and chains
It's also important to choose the chain or according to the weight of an anchor in relation to the boat. Remember that as boat length increases, the weight of an anchor in relation to the boat should increase. On the other hand, there's no need to consider the equivalent weight of an ocean liner anchor for your sailboat. Recent models are powerful enough to cope with all types of anchoring.
Choose a galvanized steel chain for greater resistance to wear and corrosion. For optimal mooring, make sure you use a chain length/depth ratio that's adapted to sailing conditions.
→ Our selection of boat anchors on Nautisports
At Nautisports, we offer a wide selection of boat anchors. Feel free to consult the online product sheets for each anchor to find out the details in terms of stock and delivery time. If you have any questions or require further information, our customer service team will reply and direct you to the product available in stock that best suits your needs.
