While stern davits seem to be the most popular way to carry your dinghy, they do have a dark side to them too. Yes, they are always present and so convenient, as they raise the dinghy from the sea, but when you head to sea, stern davits could actually damage your yacht.
A following sea presents many dangers. The approaching waves can push you into a broach as well as board your yacht. If you get boarded by a large enough wave, your yacht could be swamped and if the scuppers do not drain the water fast enough, you could be boarded again and eventually sunk! This may seem far fetched, but waves carry a lot of water in them, and this water will weigh down your yacht in under a second!
Carrying a dinghy in davits while sailing in a following sea is akin to dangling fresh meat in front of an attack dog, at some point, you will get bitten!
A dangling dinghy in davits will hold the water of a boarding wave very well, as the only way for the water to drain out is through that little drain plug in the stern. Waves in the ocean run in a wave period of seconds, meaning that the next wave is only a few seconds away! In the Atlantic Ocean, the wave period is usually around 4 seconds. If you get hit by a wave, the next one will strike in 4 seconds! There is no way the drain hole will evacuate that much water in such a short amount of time.
What will happen is the dinghy will get filled by the first boarding wave and the weight of it will either rip out your davits, creating a set of holes in your stern, or collapse your davits, causing you to drag a broadside dinghy in the following sea. Either way, your dinghy will turn into a drouge and you will have some costly repairs to look forward to.
If the dinghy doesn't break the davits, then another problem will come to light. The weight of the dinghy, full of water, hanging off the stern will pull the transom down, making the cockpit that much closer to the waves. This makes it even easier for waves to board as your stern squats into the water. The aft tilt will also rake your mast back, causing you to have a greater amount of weather helm, adding to more difficulty in steering.
As the first wave hits, the dinghy will fill with water and the immense weight will pull you down. In 4 seconds, the next wave will hit and come into the cockpit. In all the confusion, you might let go of the helm and try to figure out how to get all of this water out of the cockpit and dinghy, but 4 more seconds have passed and then next wave is striking. This wave boards as well and gives you a bit of a push. Combine this with the weather helm and the yacht will round up into the wind, broaching in the following seas.
This scenario may sound far fetched or rare, but it is only possible if you have a dinghy hanging in stern davits. Stern davits are ridiculously convenient to use while coastal cruising. You leave one anchorage, hoist the dinghy, arrive at the next one and drop the dinghy! But if you decide to sail a longer distance or cross an ocean where you won't be using the dinghy for a while, it would behoove you to hoist the dinghy onto the deck and lash it down upside down so that it can't fill with water from a boarding wave.