Every boat behaves a bit different from others. .
Finally, someone hits the rest of the story. It's not a quick brush of FD vs. SD, whatever that means or Semi-planing or planing. It's not even brands. So many factors and then it's the conditions and location. What each of us need to do is learn all we can about out boat and what to do with it in various situations we may find ourselves in. Every boat owner should have plans and comfort models on every boat. We own boats of different sizes and speeds which may all fall under the same general types but are not at all alike in terms of rough conditions.
For instance, a 40' boat that cruises at 35 knots has the great luxury of being able to quickly get to shore on any sign conditions are changing. It can even take moderate waves with fairly short periods and smooth them out at speed. However, if you were to try to handle 8' seas at hull speed in that boat you're going to be up and down and very uncomfortable.
Meanwhile go to a larger, slower boat such as an 85' which cruises at 20-22 knots and at hull speed it would handle the same conditions more comfortably. While the 40' boat above never really assumes the posture of a full displacement boat, the 85' can at hull speed. At that point it behaves much like a full displacement boat with the exception of only having a 5' draft so never as much depth or as much weight under the water surface. Less natural ballast.
When it comes to forecasts, with either of the above boats you're dealing with a very short window in which the forecast must be accurate and the forecasts are nearly always reasonably accurate within those windows.
The vast majority of cruising by TF members is something I term Coastal in nature and that included the Gulf of Mexico and the Gulf of Alaska. If you're within 200 nm of a coast, then I use the USCG definition and call that coastal. You can then cruise from Halifax, Nova Scotia or beyond to Anchorage, Alaska and all be coastal. You can cruise the Caribbean and all be coastal. I know that's a very broad definition but it's also one that fits into sea forecasting. Even at 6 knots, 200 nm is only 34 hours and our forecasts are very accurate within those ranges. Now someone did mention PNW Bar crossing. That is an area of concern. The CG does a great job of forecasting bar conditions and warning. When we cruised that area, our thoughts were get in at the first sign of trouble ahead and if that meant not making it to our original destination, then do it. The issues I'm aware of haven't come from inadequate warnings but from those not heeding them.
Now, as to passage making, we have only a few members here who do so. I consider it anything that takes us more than 200 nm from shore. Our longest trip to date was about 1000 nm from St. Thomas to Fort Lauderdale moving by the DR and then by Cuba. Now, not sure we should count a shore which wouldn't have liked us suddenly dropping in. We've done similar runs off the US coast but felt far less like we were doing a passage on them. We've planned a future Atlantic crossing and recognize there the entirely different risks and weather windows. We'll not be in a FD boat which the vast majority of those crossing are in. The longest single crossing will be Bermuda to the Azores if we take that route, just under 2000 nm. The facts the planned boat can cruise at 20 knots or that it has 3000 nm range are nice but mutually exclusive. 3000 nm is at 11 knots, 20 knot range only 1500 nm. We would anticipate then being 1000 nm from land and a speed of 12-15 knots so a maximum of 80 hours or 3 1/3 days. A boat crossing at 6 knots would reach a maximum of 170 hours or just over 7 days from shore on a 14 day crossing. In that area, the forecasting for 2 to 3 weeks is remarkably accurate so likely no unexpected systems but any can be degrees worse than expected. As to drogues, absolutely would have one for that trip.
One major element that concerns us and is less often mentioned is a true medical emergency at sea. When you're going to be days from possible medical care, you need to recognize that risk. We've undergone training, are equipped, and do subscribe to a service.
I believe in one doing their best to plan for all possible events, but that still doesn't mean everything. You plan for what might impact you on a specific boat doing specific cruising with specific people. Then plan for alternatives too if appropriate, but can't plan for the entire universe of situations that might impact the universe of boaters and boats.
