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What Water Depth is Suitable for My Boat?

 

If you aren’t clear about your boat’s draft, you could land yourself in serious trouble. In this article, we will look at the draft of various common types of boats so read on to avoid getting stuck in the mud.

First off, here is the average draft for some of the most popular types of boats:

  • Daysailer: 3-5 feet
  • Sailboat cruiser: 4-7 feet
  • Motor yacht cruiser: 1-4 feet
  • Catamaran: 2-4 feet
  • Dinghy: several inches
  • Trawlers: 8 feet or more

Please bear in mind that these numbers are not precise and depend on a number of factors. Let’s look at a little more detail about boat drafts and give you some insight into how to avoid running into trouble.

What is a boat draft and why do I need to know?

If you are not familiar with the term ‘draft’ (or ‘draught’) in relation to boating, it is the distance between the surface of the water and the deepest point the boat’s hull breaches to underwater. This means that the draft value is equal to the minimum water depth your boat can safely be in. If you move into shallower water, you will scrape the bottom of your boat and may do some damage or even become stuck.

It is essential to know the draft of a boat before you take it out. In a car, if you underestimate the size of a gap and accidentally scrape the paintwork, the only consequence is a frustrating repair fee. But if your boat makes contact with the sea bed the consequences can be much more severe.

Depending on what the sea bed you hit consists of (sand, rocks, seaweed, etc.) the outcome will be different. You may simply get beached, or your propellers may become tangled in whatever is beneath you. You could even pierce a hole in your boat’s hull.

Be advised that repairs for boats are not cheap, even if you merely scraped the surface with a glancing blow. It can cost a lot just to be towed to a safe location, and there is a risk that this will damage your boat further. In a nutshell, if you fail to respect your draft it can be disastrous for your bank balance and may cause your relaxing cruise to descend into a logistical nightmare.

Whatever boat you use, be aware of your draft at all times. The number is usually printed clearly in the cockpit, or you can find it in the boat’s manual. The internet is another good place to look. It is wise to double the value for safety’s sake, and avoid going into places where the plotter shows a number less than twice your boat’s draft. If you lack a depth measuring device and are simply following a chart, be even more careful.

Daysailer: 3-5 feet draft

These boats usually measure 14-20 feet long. Generally speaking, the larger the boat, the greater its draft. One advantage of these smaller boats is that the keep is often retractable, so you get that extra stability when sailing but can reduce the draft from several feet to a matter of inches when it’s time to dock.

Sailboat cruiser: 4-7 feet draft

This is the common boat type for a typical cruise. It is a classic sailboat with a length of 30-50 feet, and its draft typically comes in at 4-7 feet. It is the keel that makes up the majority of this deep draft – it is there to offer greater stability when out on the waves. You should always be aware of this long piece of steel that protrudes downwards from the boat’s centre, particularly as you come closer to shore.

Motor yacht cruiser: 1-4 feet draft

The number is low here because motor yachts come without a keel. They aren’t technically needed on these boats, but that does not mean you can let your guard down. That draft of 1-4 feet must still be respected, and it is less of a problem to scrape some paint off your keep than it is to pierce a hold in your hull.

Catamaran: 2-4 feet draft

Catamarans generally have similar proportions to the sailboat cruiser. However, they have a smaller draft because the catamaran has fantastic stability by design. They have two keels, so those keels are smaller, and the dual hulls offer greater buoyancy to reduce the amount the vessel cuts into the water.

The result is that you can usually enter shallower waters than you would be able to with a similarly-sized monohull. Nevertheless, be aware of your specific draft or you will end up scraping to the bottoms instead of just one.

Dinghy: draft of a few inches

Dinghies are great for moving through the shallower water. That’s why we use them to get to shore when we drop anchor in a nice bay. Their draft is no more than a few inches and they are very lightweight, with bottoms designed to withstand abuse from different types of seabed contact. In other words, you are pretty safe to drive your dinghy directly onto the beach.

Trawlers: lots of draft

It is unlikely you are planning to captain a large fishing trawler, but they give a good idea of where you can take your average boat. Even the smallest trawlers tend to have an 8-feet draft, so you can be sure you are in a safe zone if you are in the same area as a trawler. They can be a good point of reference when you have no instruments and are feeling uncertain.

The bottom line

Drafts are not rocket science. It’s essential to know your draft before you head out to sea, and it is usually written down in a prominent place. Add an amount you are comfortable with to provide a little cushion for safety and be mindful of what your depth meter is indicating at all times. The depth is generally measured from the hull’s deepest point, so it may not account for the keel.

If you don’t have a depth meter, use your maps as a guide. They will give you the information you need to take precautions, but you may want to consider investing in a depth meter. Use your judgment and only take your boat into safe areas. You don’t want to face the consequences of damaging your boat – it really isn’t worth the trouble.