It is relatively easy to find out the speed limit on a road while driving a car since all you have to do is to look out for a speed limit board on the roadside. But, what about boats? Do boats have speed limits (like other land vehicles), or don’t have any speed limits?
Boats usually don’t have any speed limits like other land vehicles, but there are some restrictions like a “no-wake zone” in the areas around other boats, docks, piers, ports, canals, bridges, etc. Unless if you boat in those areas, probably there won’t be any speed limits for boats, and you can go fast.
No wake means you can’t make waves, meaning you have to go really slow (usually less than 5 MPH will not create any wakes). If there are any small boaters around, and if you make wakes, those wakes can toss the small boaters out of their seats and can sometimes be hazardous.
Usually, if there are no boaters or lighter boat traffic around, you can go at a good pace (fast), but you have to slow down if there are any speed limit signs. And the boat speed limit is rarely a specific numerical value. In open waters, like oceans or seas, you can go at top speed, assuming it’s safe and clear out there.
Since open waters like oceans or seas are international territories, no one owns them, and most probably, no one will be out there trying to find out how fast your vessel is going. If you can manage 100 MPH across the ocean or sea well, you can go fast. So, there won’t be any speed limits in oceans or seas.
Most presumably at the shore of the lakes, rivers, seas, etc., and in the bays or other such areas where the probability of boat traffic will be more, you need to be more cautious. As a boater, you need to keep these things in mind while spinning (boating) out in the waters.
How fast do boats go? (Do boats go fast in general)
Even if you have all the available time in the world, Do you prefer going slow? Or you wanna go fast? Generally, we know at what pace cars and bikes will move. But what about boats? Do boats go fast in general? Or do they go slow?
The boats that are used by many people (mostly recreational boats) will not go that fast. On average, a recreational boat will go at 10-40 MPH, which isn’t quite fast (though installing extra motors will give a boost). But, considering speed boats that can achieve 100 MPH may imply, boats are fast.
Yeah, boats go fast if you consider cigarette boats or racing boats like the Spirit of Australia, which holds the record speed of 317.6 MPH. But considering the more general cases like recreational boats, which most people use (that go at 10 – 40 MPH on average), then boats won’t go quite that fast.
The majority is kind of vital here because many people will not be using speed boats (cigarette boats that can achieve 100 MPH), which are quite faster. So, considering that, boats won’t go quite that fast. The main reason why boats won’t go fast is it is moving in a fluid medium, which has more frictional resistance.
Even if the boat and car have the same engine and raced in ideal conditions, the boat will not win the race because water is denser than air and always provides more friction than air. And mainly the boat needs to push the water in its way too, but the car has nothing to push, just the air.
We will now see some of the popular boat speeds (both average speed and top speed). By looking at those values, you will get some idea about some of the popular boat top and average speeds. These are just average (approximate values); sometimes, a boat can exceed that speed and may not.
|Type of boat
|15mph – 30mph
|30 mph – 50 mph
|30 mph – 40 mph
|40 mph – 60 mph
|15 mph – 35 mph
|30 mph – 50 mph
|16 mph – 30 mph
|100 mph – 150 mph
|150 mph – 200 mph
You can clearly see that most of the boat average speeds are below 50 MPH, which is fast for many people, but not quite (more) fast. So, boats won’t go that fast (as far as recreational boats considered, which are used by most people in general than speed boats like cigarette boats, racing boats, etc.).
Related post – Check my article on Boat vs. Jetski, which ones are faster to know whether all three types of PWCs (jet skis, wave runner, sea doo) are faster than boats or not.
Check this short video on Ken Warby achieving the world record boat speed in the late 1970s using the Spirit of Australia (boat) and to know why that is considered as one of the deadliest records to beat, even till now.
Are boats faster than cars?
Boats aren’t faster than boats because water is denser than air, and the boat needs more power to push the water out in its way (more friction). Simultaneously, cars are just moving through the air without pushing any (less friction). So, boats don’t go faster than cars.
The main reason behind the slowness of a boat is friction. The frictional resistance is more between the water and the boat’s hull. When you keep the boat in water, it displaces the same amount of space in the water, which is equivalent to the boat’s weight.
Meaning, if your boat weighs 1000 pounds and you kept your boat in water, the boat displaces the same space in the water, which is equivalent to 1000 pounds. Whenever you are boating, the boat pushes the boat’s equivalent weight of water away every time, which slows down the boat a bit.
So, it requires more power to push the water away on its way. Since the water is denser than air, the boat requires more power to push the water out of its way. More friction is making a boat to move slowly. On the other hand, the car is not pushing anything which is denser than water on its way.
The car has to overcome its frictional components in the drivetrain or driveline, friction between the tire and the surface (road), and the air. And the car is moving against a solid surface (road), unlike the boat is moving against a fluid surface (water). So, boats go slower than cars.
Related post – Check my article on Do boats go faster than cars? to know all the reasons why boats go slower than cars in a detailed way.
Check this small and fascinating video on Boat vs. Car vs. Bike race to know how fast they have traveled, leaving the boat far behind.
What affects (reduces) the boat speed?
Going fast in a boat can be lots of fun, but some external factors apply some brakes to the boat, reducing the speed a bit. We will now see some of the external factors that affect (tries to reduce) the boat speed.
1. Boat’s hull and bow design can decrease the boat speed
The boat’s hull and bow design will affect the boat speed because if it has a planning hull and slender bow, it will not push the water away on its way like a displacement hull boat. Instead, it goes on top of it by making less contact with water, which will increase the boat speed a bit.
The displacement hulled boat tries to push the water away on its way, whereas the planning hull boat will try to go on top of the water with minimal contact with the water. Pushing the water away on its way will decrease the boat speed for a displacement hulled boat.
More contact with the water means more friction, and if the friction is more, it reduces the boat speed. For example, only the prop and lower unit remain in the water at high speeds in a bass boat. For a displacement hulled boat, 1/3rd to 1/5th of the boat will be in contact with the water.
So, the boat’s hull and bow design are crucial for a boat to achieve good speeds. If you are looking for a speed boat, better go with a planning hull and slender bow designs to get the max out of it (only if you don’t concern about less storage because a planning hull boat will have less storage space than displacement and semi-displacement/planing hulled boats).
2. Low water depths (shallow waters) will decrease the boat speed
Shallow waters reduce the boat speed because the water flowing under the boat moves fast in shallow waters, creating high velocity, which lowers the pressure under the boat; thus, the boat sinks more and displaces more water. So, the boat needs to push more water on its way, which lowers the speed.
The draft of the boat will increase in shallow waters because, in shallow waters, the boat will be moving so close to the ground, and there is less space for the water to flow under the boat, which increases the water flow under the boat (velocity at that particular point in the water increases).
From Bernoulli’s principle, if the velocity is high at any point in the liquid, then there is a corresponding drop in the pressure at the point. Generally, the pressure is required to lift the boat in the water, and if that pressure decreases, the boat will sink more in water, thereby increasing the draft.
If the boat’s draft increases, the boat displaces more space in the water, and the boat needs to push more water out of its way. Pushing more water out of its way means the boat takes more power and time to push that extra water out of its way, decreasing the boat speed a bit.
Related post – Check my article on Why does a boat speed slows down in shallow waters? to know more about what affects the boat speed in shallow waters in a detailed way.
3. Low water temperatures will decrease the boat speed
Coldwater decreases the boat speed because water’s viscosity increases if the water’s temperature drops, which increases the intermolecular attraction between the water molecule (increasing the thickness of water molecules). It becomes harder for a boat to move, so boat speed reduces in cold waters.
Viscosity increases with a decrease in water temperature. If water temperature decreases more, then viscosity increases more (meaning the water molecules’ intermolecular attraction increases, which increases the water’s thickness). So, the boat speed decreases if water temperature decreases.
As the water becomes more viscous, frictional resistance increases between the boat’s hull and the water, which eventually decreases the boat speed in cold water. But, it’s only a small decrease in speed, not a noticeable decrease in speed.
Related post – Check my article on Why boat speed decreases in cold water? to know more about the reduction of the boat speed in cold waters in a detailed way.
4. Boat speed decreases if the boat is heavy
Boat speed decreases if the boat is heavy because a boat displaces more space in the water if the boat is heavy, and the boat needs to push that (more) water out of its way, which requires more power and time, decreasing the boat speed. So lighter the boat, the faster you go.
When you keep the boat in water, it displaces the same amount of space in the water, which is equivalent to the boat’s weight. Meaning, if your boat weighs 1000 pounds and you kept your boat in water, the boat displaces the same space in the water, which is equivalent to 1000 pounds.
Whenever you are boating in water, the boat is displacing (pushing the water away) the boat’s weight of water, every time. If the boat weight increases, it displaces more water, and it needs to push more water out of its way, which means the boat takes more power and time to push that extra water out of its way, decreasing the boat speed.
Those are some of the main reasons that effects (decreases) the boat speed. However, you may not see the difference in speed reduction; it won’t be a noticeable difference.
Relayed post – Check my article on Essential factors that affects the boat speed to know about all the above factors in a detailed way.
Boats have speed limits in the areas around other boaters, docks, piers, ports, canals, bridges, etc. Other than those places, there won’t be any speed limits for boats, and you can go fast. And in open waters like oceans or seas, there won’t be any speed limits for boats.
Generally, there will be “no-wake zone” signs in the area around other boaters, docks, marina, ports, etc. No wake means you can’t make waves, meaning you have to go really slow (usually less than 5 MPH will not create any wakes).
If there are any small boaters around, and if you go fast and make wakes, those wakes can sometimes toss the small boaters out of their seats and sometimes be hazardous, like a big wake can capsize a small boat easily.