Originally Posted by SVNeko
Its not just daggerboards. Weight and hull shape (wetted surface area) have more to do with it. Daggers will allow you to sail closer to the wind and sometimes mean less drag than keels. But they do indicate a build that is at least trying to optimize speed.
There are a few videos on YouTube showing a Gunboat sailing at 20 kts boat speed. There is also a YouTube video of a Catana 90 crossing the Atlantic. In both videos the videographer shows shots of the water flow at the bow(s) and the water flow leaving the transoms (exhaust).
The Gunboat (I think it's an older 66) is also filmed sailing at 6 kts in 5 kts true wind - that tells a huge story right there. Most cruising cats large or small, will be barely moving in 5 kts of true wind. But what tells the biggest story is the respective video of the water flow leaving the transoms. The Gunboat sailing at 20 kts boat speed has a very clean, laminar water flow leaving the transoms. The Catana 90 is doing only 13 kts in 22 kts of wind but significantly the water flow off the transoms is very turbulent, almost boiling. This quantifies to drag. A lot of drag. Both boats are reaching in trade
wind conditions with give or take, 20 kts of true wind.
Obviously, the 90ft Catana is a lot heavier but with a LWL of around 90ft and a rig to match, it should more than make up for it. The difference is the lightness, stiffness, hull design, dagger board/rudder form, balance - the video can't lie like manufacturers polars or displacement
The gunboat literally slices through the water with minimal exhaust
. Just like you want an aircraft wing or your sails to do - laminar airflow at leading edge, around and exiting the hull form, wing or sail. Yes, many racing
cats, tris & even monos achieve this. But the Gunboat is a cruising boat.... They sail like this with water makers, dishwashers, washing
machines, gen sets, water toys and diving gear
plus a dinghy
hanging off the davits
. Is it worth 3 mil? I don't know and for me it's a moot point; I have to stick with my second hand L440 for now. It's comfortable and sails pretty well for a heavy, high windage cruising cat with mini keels. I think if you can afford a 3 million dollar boat it will also be a moot point. Carbon is a lot more expensive than glass mat, that's for sure.
I like Catanas, outremers, & many other faster, comfortable (we're cruising after all) sailing cats. But I think what Peter Johnstone and M & M have achieved is remarkable. It will be interesting to see how the new Gunboat designs fare.
I have nothing to do with Gunboat, Peter Johnstone, M & M or anyone affiliated with them. I like the boat, I like his philosophy regarding cat design. That's it. Watch the videos, look at the water flow, look at the wind instruments.... Very telling.