I just got an old Solcat 18 and I'm all geeked out fixing it up so it will be ready come springtime (It was 30 degrees in Chicago last night!). I'm sorry to be bugging you all with annoying newbie questions but I don't think that my dolphin striker is original and I'm wondering if it is ok. The angled part that takes up the tension is made of a 1"x 3/16" strip of aluminum that is attached at each end with two bolts to the crossbeam. This piece seems loose when the mast is not stepped as there is about 1/2 inch of play in this piece almost like it is under compression instead of tension. I think the cross beam will be allowed to flex quite a bit before the dolphin striker would tighten up and take up the load. Does the dolphin striker only tighten up when under the load of the stepped mast or should this be pre-tensioned even when under no load? I have plenty of thread left on the rod to tension it but I don't know how tight it should be. I didn't see anything about tensioning the dolphin striker in the technical section.

hi Tex, i went through similar when i disassembled my 17 foot nacra's front beam

basically you want to assemble the beam flat, then adjust the dolphin striker until it forces the mast base up about 5-6mm, then lock it in at that.

that way when the 50lb? mast goes on and gets loaded with another 100lb? by the sidestays it ends up working against the uplift and forces it down closer to flat

if you can't do that, then there is something wrong

perhaps if you post a photo of what you have, other solcat owners can tell you if there's is the same

Ok, I'll try to post a picture below. I have stripped all the old paint off of the cross arm so please exuse the ugly bare metal. You can see the bow in the far side of the dolphin stiker. There is about a 1/2" bow on each side. The cross arm is straight as an arrow. I assume this bow is wrong and the bolt should be tighteded up as erice mentioned in his post (Thanks erice!) If anyone has any other comments on how to do this, please let me know. Thanks!

hi Tex, that bow is bad, it should all be tight

it looks like what you need to do is adjust that nut we can see on the beam so the dolphin-striker post gets "longer" and takes the slack out of the strap. you'll have to loosen the nut on the other side of the beam and hope you've got enough of the dolphin-striker on the other side to take all the slack out.

once all the slack is gone you need to tape a fine bit of thread on this side of the beam so that the thread is as close to the nut as possible but not touching it. then keep forcing the dolphin-striker down so that the straps tighten up and force the beam upwards into a slight curve. stop when the gap between the thread and the beam is at about 5mm. you should have now pre-tensioned the beam enough to counteract the mast and rigging loads.
when you are done is usually a good idea to cover the nuts and fill the threads with bathroom silicon sealantto stop corrosion



edited by: erice, Oct 12, 2009 - 07:24 PM

You might also want to check if the dolphin striker post is straight, it looks like there's sag only on one side suggesting the post may be bent. Can you post a pic of the cross beam turned over so we can see the mast step?

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TurboHobo
H14T
H16
P18
G-Cat 5.0
P16
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PS in answer to your question above

Quote

or should this be pre-tensioned even when under no load?

the answer is yes the cross bar/beam should be pre-tensioned. I'm hoping that some SolCat owners will be able advise on that and to answer your other question as to wether it is original.

--
TurboHobo
H14T
H16
P18
G-Cat 5.0
P16
--