Adding weight onboard can make quite a difference to stability, performance and even comfort.
There are two points to be considered. The loading of fixed items like furniture and tanks, and the loading of everything else that you take on to the boat. Boat speed is of great importance to all of us and the amount of loading on the hull is paramount. The approach to this problem should be weight, balance, and space.
Static weight like the hull, fuel, water, furniture, appliances and motors is usually considered by the designer. Should you be building your own hull you need to be thinking about this weight problem constantly. More weight in a catamaran, for instance, can significantly alter performance. Given that all these things are usually in the hull when you buy it, you may need to think about how you reduce it a little and how you will stop yourself adding to it. Added weight is insidious in that you seem to add to it as the years go by without taking any steps to reduce it. You will never know how much extra fuel it will cost you or how much time and sailing pleasure it will cost. Just have a look around your boat and see how many books you have on board. How many have been read and kept, never to be referred to again? Are there ones simply brought with the off chance of reading them? How many have not been opened in the past 12 months? Now put some of these in a cardboard box and lift it, just to consider how much weight there is. There is every chance you have at least 50kg of books and magazines that you can get off the boat. You need to be positive and determined in your quest to lighten the boat. You may have large fuel and water tanks that will come in handy when you go on an overseas cruise. But do you really need to keep them full all the time when you are coastal cruising? You may be cruising in an older designed boat that could be lightened considerably by using modern space-age gear that was not invented when your boat was built. For instance, you may have a spinnaker pole strapped to the deck and you never use one. Old cruising sails that are very heavy can be replaced with more modern, lighter sail cloth. Not only will the weight be relieved, but the boat will sail better and the sails will be easier to handle.
The balance of the boat will be determined by the weight and where it is placed. This balance will affect the way the boat sails and steers as well as its speed. The ultimate balance is to have all the weight in the centre of the boat and as low down as possible. Some boats have a permanent list caused by the location of the furniture and fittings. One heavy item like a fridge on one side of the hull should be countered by a similar weight object on the other. Items that can be moved if you are overloaded on one side are gas bottles, batteries, tool boxes, and dry food. Does your boat sit down by the bow or the stern? Just how much anchor chain are you carrying? When was the last time you deployed more than 50m of chain? You can always add rope for that once in a lifetime you are going to anchor in deep water. When you lift the dinghy on to the davits, does it raise the bow and how does that affect the sailing speed and comfort? If the dinghy was on the foredeck, would it be better? You have a ready-made lifting device in the spare halyard and mast winch. Some owners who buy a used boat may never know the true waterline designed for it. It could, for instance, be several centimetres deeper in the water when you buy it. Try reducing the weight in your boat and see how much higher it rides on the water line. This all transmits to better and faster sailing. On the subject of balance, you should anchor the boat in very shallow water some time so there is only about 30cm under the keel and then dive down and note whether the bottom of the keel is parallel to the flat seabed or if it is deeper at the bow or stern. While you are there, imagine the probable angle it would have on the hard should you ever go aground. It may assist you to get it off quickly in the case of a falling tide. The idea is to keep the weight in the hull low down so we always try to have the boat designed with the tanks and battery storage in the bilges. This lessens the leaning effect of the sails and also lessens the roll. So, with everything you take on the boat or build into it, give a thought about its effect on balance.
Space on board is the one thing we never have enough of and are always looking for more. By the time you get rid of a heap of those books you will find more space. Most of us cruise the coast and are never more than a day?s sail away from a supermarket so why do we carry so much tinned and dry food? It is all weight and space. Do you really need to carry those extra fuel and water drums on the deck? They also take up space and weight. When looking for more space, have you ever considered the spare space available in the anchor locker? One of the biggest users of space is sails. How many bags of sails do you have stored down below that you will probably never use? Yet more bulk and weight that affects your sailing ability. The average cruiser has all the sails he needs above decks. Spare sails affect the balance of the boat as well. I can hear you say to yourself that when you bought the boat it had all these bags of sails down below and you are loath to get rid of them and you might want them some time. Well, take them off the boat and store then ashore. You are only coastal cruising and can access them at short notice. Big 9kg gas bottles take up nearly twice the space and weight of a 4.5kg bottle. You may have to fill them a bit more often but so what? Going through your boat and getting rid of unnecessary gear will give you more space, better balance and more speed and so more enjoyment of your sailing.