2 ms·

I wonder if a lot of the confusion in this discussion is for the same reason I was confused - most descriptions of a sea anchor are missing the details of why i

I wonder if a lot of the confusion in this discussion is for the same reason I was confused - most descriptions of a sea anchor are missing the details of why it works, and calling one style a "parachute" makes it even worse IMO. Hopefully some folks with actual marine experience can correct me if I'm wrong here, but based on the most descriptive source I could find[1], this is what's going on: For a traditional sea anchor (including the ones that look like parachutes), the force of the waves is pushing the anchor away from the vessel. The anchor is either submerged or very low profile, so wind/air resistance effects on it are nonexistent or negligible. i.e. the anchor should be moving in exactly the same direction as the waves. Meanwhile, the vessel sticks up well above the waterline, so there is resistance from the air itself against it being pulled in the direction of the sea anchor. This should make it always trail behind the sea anchor, being pulled in the same direction as the waves are pushing, and this keeps its long axis perpendicular to the waves so it can't roll over. In other words, if I understand correctly, this type of sea "anchor" is more like an underwater sail. This is why they're connected to the front of the vessel. For drogues, it seems like the idea is to allow the waves to push the vessel continuously (like a surfer riding a wave), with the drogue trailing from the stern and tuned to slow the vessel the exact right amount to stay in a safe position relative to the wave it's riding? [1] https://www.schoonerman.com/heaver-weather-sailing/what-is-a-sea-anchor.html https://www.schoonerman.com/heaver-weather-sailing/what-is-a...

closewith 4y ago
> For a traditional sea anchor (including the ones that look like parachutes), the force of the waves is pushing the anchor away from the vessel. It's actually the opposite of this. A sea anchor acts like a parachute in that it slows the vessel by increasing drag (although obviously with water as the medium). As with a parachute, where the parachutist will always be below (excepting acrobatics) the canopy as both are falling in the same direction through the air, a sea anchor behaves the same way in the water. So both the vessel and sea anchor are being pushed by waves, like the parachutist and canopy are being pulled by gravity, but the submerged sea anchor (down in calmer waters below the largest influence of the waves) has greater drag than the vessel in the water and slows the vessel. In heavy seas, a vessel without a sail will have the current and sea state as the most significant influence rather than the wind (although this can vary). When deployed from the bow/front of the vessel, a sea anchor works to both slow the vessel's overall speed over ground (which can be useful to avoid excessive drift into hazards or losing progress) and it also acts to keep the bow into the weather. This is important as vessels generally are prone to damage/capsize if taking heavy seas/big waves abeam/onto their sides.
- blincoln 4y ago
  Ah, thank you. That makes a lot more sense.

closewith 4y ago

> For a traditional sea anchor (including the ones that look like parachutes), the force of the waves is pushing the anchor away from the vessel. It's actually the opposite of this. A sea anchor acts like a parachute in that it slows the vessel by increasing drag (although obviously with water as the medium). As with a parachute, where the parachutist will always be below (excepting acrobatics) the canopy as both are falling in the same direction through the air, a sea anchor behaves the same way in the water. So both the vessel and sea anchor are being pushed by waves, like the parachutist and canopy are being pulled by gravity, but the submerged sea anchor (down in calmer waters below the largest influence of the waves) has greater drag than the vessel in the water and slows the vessel. In heavy seas, a vessel without a sail will have the current and sea state as the most significant influence rather than the wind (although this can vary). When deployed from the bow/front of the vessel, a sea anchor works to both slow the vessel's overall speed over ground (which can be useful to avoid excessive drift into hazards or losing progress) and it also acts to keep the bow into the weather. This is important as vessels generally are prone to damage/capsize if taking heavy seas/big waves abeam/onto their sides.

blincoln 4y ago
Ah, thank you. That makes a lot more sense.