[MHml] Catamarans (seagull strikers)

[Roy Mills]

At 09:29 PM 9/7/06, you wrote:
>On my Sunburner 28 the seagull striker also angles parallel to the
>forestay, but it presents a problem on my boat. I have roller furling,
>and the drum has to be "above" the striker, placing it perhaps 18 to 22
>inches above the beam. This necessitates long "homemade" tangs between
>the furler drum and beam attachment point, and worse than that, the
>furler control line has to cross the tramp at knee height -- a nice
>tripping hazard just where you don't need it.
>
>I have considered moving the striker to vertical, replacing it with an
>"A" (it's a straight tube now), but have wondered how much weaker it
>would make the beam. From the comments below, It may be best to leave it
>alone.
>Chad

         I have just replaced my straight, single, seagull striker 
with an A frame so that a future owner can fit roller furling if 
desired. I found that the aluminum structure weighed exactly as much 
as the stainless one it replaced.  Dave is going to pounce on me for 
this, but to allow for this possible roller furling, it was necessary 
for the A frame to angle back slightly less than the forestay angle, 
wheras the old one was exactly the same angle. I have kept the old 
one "just in case".

          I do not consider that it has weakened the front cross beam 
at all, but then my front crossbeam is a composite diamond shaped 
skin around a wood and carbon square core, and there were enough 3/8 
diameter bolts through it for other reasons that the new structure is 
fixed very firmly to it. The important thing is that the section of 
material spanning the bottom of the A frame and to which the forestay 
is attached in the middle is strong enough to cope with the pull of 
the forestay and jib halyard. Mine is perhaps a bit of overkill, 
being a section of 6061-T6 aluminum 2.5 inches deep by 3/4 of an inch 
wide, angled back of course at the forestay angle. The feet of the A 
frame are 16 inches apart on centres.