How many kg is a dinghy

So, now we have a minimum hull weight of 70 kg and to reach that, the hull needs 15 kg!!! Where do I put them? Okay, somewhere in the middle As long as you put the weight towards the mid length of the hull rather than at the ends, it will be fine. If you want to know where the longitudinal centre of gravity is, pick the hull up by the gunwhales and find the lifting point where the point where the hull sits level, that will be roughly the LCG.

Bear in mind that the weight of the crew is a far more significant part of the total weigh than the hull weight, so technically you should work out the LCG with crew weight included, with the crew positioned in the upwind sailing position.

The object of centralising the mass of the boat is to reduce the pitching moment of inertia, allowing the hull to rise and fall more easily over waves rather than stuffing the bow into the wave fronts , hence upwind crew position because the highest frequency wave encounters occur when sailing upwind.

Just behind the centreboard when its fully down is usually a fair bet. If there's a thwart then under that. However you should read your class rules carefully, because they usually have something to say about where corrector weights may be placed.

Centre of buoyancy? Isn't that supposed to be in the same longitudinal position as the Centre of Gravity? And what about this thing called "Centre of Floatation" And if not, why not put the weight there???

What about centre of pitching, this is relevant if the boat is sailed flat? This is normally above the deck! What kind of boat is it? Planning on racing it, then consult your class rules. I seem to recall, Rodney Patterson favoured putting it at the back of the CB case, as when he observed boats sailing upwind in a chop, this seemed to be the centre of pitching rotation, i.

Watch footage from your class? Yes, in static trim, the centre of bouyancy will be directly above or below the centre of gravity. The longitudinal centre of floatation, determined by the centroid of the waterplane area, is the axis about which the boat will trim in the static condition flat water, no waves. However, the actual motion of a boat in waves is a combination of pitch and heave.

Adding the two together, the actual pitch centre may be a point somewhere aft of the transom! What determines a boats ability to respond to pitching forces is the pitch moment of inertia, which is determined by the mass distribution about the centre of gravity.

The commonly accepted theory is to reduce the pitch moment of inertia to try to reduce hull drag caused by dragging the ends of the boat in and out of the waves. There may be a case for putting the mass aft, closer to the true pitch centre, to reduce drag due to heaving.

The problem with that is that the boat still has to trim correctly, so if you move one mass aft, you have to move another the crew forward to compensate. The theory about reducing pitch moment of inertia is moot in itself. First of all, you can only calculate dry weight when a boat is empty and dry.

Displacement is equal to the weight of a boat, along with everything and everyone aboard at the time of measurement. This includes water, fuel, deck equipment, interior cushions—you get the picture. The most common measurement of weight for sailboats is displacement, and it reflects the weight of a loaded sailboat in the water.

We measure displacement by calculating the weight of the water volume a boat displaces. This unit is vital in boat design. A vessel will sink if it weighs more than the water it displaces. Imagine a cup of water filled to the very top. Now drop in a coin and measure the amount of water that spills out. The weight of the spilled liquid is the displacement of the coin. Oddly, the displacement value of a boat means slightly different things in salt and freshwater. Saltwater weighs So, how does displacement translate to weight?

Simply divide the displacement by 2, to get your answer. Put this number aside for a moment. Take this value and raise it to the power of 3. It should look something like this: LWL x 0. The displacement to length ratio is useful for a number of reasons. Tonnage represents the volume of the enclosed space on a boat, using the same concept as displacement. Salt and freshwater tonnage differ for the same reasons as well. Tonnage and size are directly related, and this unit gives you an idea of how much cargo you can carry before overloading.

Cargo tonnage is measured in long tons, similar to displacement. Simply divide the tonnage in pounds by 2, to get your cargo tonnage value. Displacement and dry weight are closely related.

Tonnage is essential to understand, especially for offshore cruising. Using this value, you can calculate how much food, water, supplies, and how many people you can take aboard. We found the specifications of three common sailboats so you can get an idea of what to expect. It has three benches and is meant to be steered from the rear. Bowrider boats are great for short cruises and are usually meant with seating comfort in mind. They will often have an inboard motor at the rear but can also be equipped with an outboard motor instead.

These boats are steered from a console, and there is a windshield protecting the driver as well as the person next to the driver. Bowrider boats come in a lot of different lengths, but the most popular length seems to be 21 feet. The main material used to make this boat is fiberglass. Fiberglass is heavier than aluminum, so this adds some weight to the boat.

The Regal 21 is a foot fiberglass bowrider with an outboard motor. It can hold up to 10 passengers and has a large wrap-around windshield. This boat is a foot long boat with a fiberglass hull. It has an inboard motor and a nice deck at the rear of the boat. Additional features include a large windshield, wraparound seating near the steering console, and a set of lounge chairs at the bow. There is also a built-in ladder at the rear for boarding. A cabin cruiser is essentially a small yacht that ranges in size between 25 — 45 feet.

These boats have large fuel tanks and will often feature more than one engine. With Examples. These boats vary in weight, but a 35 footer will usually range in weight from 12, to 16, pounds.

This boat is a foot long craft with sunbathing decks on the bow and the stern of the boat. It has an inboard motor with a fantastic deck built into the stern for getting in and out of the water.

The fuel tank on this boat is gallons, and the freshwater capacity is 50 gallons. There is also a waste tank that can hold up to 30 gallons. Cuddy cabin boats are a cross between bowrider boats and cabin cruisers.

They have the short-term cruising capabilities of a bowrider, but they also have a small area to sleep or eat inside. This area usually consists of nothing more than a berth or a berth that can be converted into a dinette.

It is great for people looking to spend a night out on the water but not very good for people looking to spend an entire weekend out there.

A cuddy cabin is somewhat larger than your average bowrider but smaller than a cabin cruiser. You can expect to find them in the 20 to foot range. The boat has outside seating for about four people while in motion and seating inside the interior space for two to three people.

Deck boats are built for day cruises and family fun. Their design gives them a lot of deck space so that you can bring your large family or a bunch of friends out on the water with you. These boats are similar to pontoon boats in that they offer a lot of room to move around.

However, they are built with a traditional hull, so they stand up to rough water better than a pontoon boat. The size of this boat usually ranges between 20 and 30 feet. Expect these boats to weigh between 3, to 5, pounds. It weighs 3, pounds dry and 5, pounds dry if you include the trailer.

This weight includes a HP outboard engine.