I have been reading a discussion of in-mast mainsail furlers and no one seems to distinguish between furlers. I have heard of out-of-mast furlers (which are said to be very poor performers), and I have seen at least two types of in-mast furlers.
The first type is one that rolls the mailsail up through a narrow slot which, it is said, will bind a sail if there are wrinkles in the sail.
The other uses a mast which acts like a cowling for the furled sail and is constructed of 2 U-shaped extrusions, one smaller than the other and fit into the larger and welded together at the edges. The sail is then furled into the vertical concavity of the smaller extruded section. This method of furling seems as though it is much less likely to bind the sail, but more like the out-of-mast furlers.
Does anyone have experiences that would help me to understand the practical differences between these three types of furlers?