Most SL sailboats boats use a sculpted boom and sails that rotate around the mast as the sheets adjust for differing wind angles.
To accomplish this effect, the visual object is just part of an underlying, larger sculpted prim form that has the mast as it’s center of rotation. In the figure below, the upper image shows my Leetle Cat II with the sails deployed, as it usually looks. In the lower image however, I’ve edited the boom to show the boom’s underlying prim shape. It reveals that the boom actually extends on both sides of the mast, although under normal circumstances a sailor only sees the sculpted view half that extends aft over the cockpit.
The sculpti effect looks very pretty, but here’s the trouble: the actual collision cage for the visible boom ( the surface that hits things) is defined by the underlying torus prim shape. There’s a mismatch between “the boat you see” and “the invisible boat that hits other stuff.”
To resolve this problem, on many boats the boom and sails are phantom.
The present fleet of Trudeau boats all use a phantom rig while underway. In contrast, the hulls are carefully constructed to ensure a realistic contact point when you run the bow or forequarter into a dock, or into the stern of that slowpoke racing in front of you.
Unfortunately, Second Life recently had a major upgrade to its servers that included a new version of the havok physics engine, and the system was deployed while bugs were still unresolved. It’s no surprise that a number of major and minor problems ensued, and I’m sure more will surface.
As I understand it (which is poorly, at best 🙂 ), some aspect of the server upgrade interferes with how the phantom rig is rezzed on Trudeau boats. Although the boat looks ok an appears to handle normally, the boom and sails are no longer phantom; they slam into things that contact the collision cage of their base prim form. As mentioned above, that can be a long distance from the apparent, visible rigging.
The Fix is In.
Well, if you have a Trudeau boat, never fear; Trudeau Yachts is on top of the issue, and a fleet-wide fix is already in the works.
I had a chance to sail the pre-release Leetle Cat II v1.17 beta yesterday, and it looks like things are back to normal, phantom-wise. 🙂 You can expect to see the automatic upgrade when you rez, as soon as Trudeau is convinced the new fix doesn’t cause further troubles. 🙂