Hello friends. While I am going through my 5.8 this winter, I want to be sure and check/understand my dolphin striker. Boat was built in 1990 and likely is original. I will definitely replace the ball at the top of the rod, but could someone tell me what I should do to make sure the striker is adjusted correctly? Thanks.
The general rule of thumb on a boat with straight crossbars would be to tighten the striker so that the crossbar has a very slight upward bend (like 1/16” - 1/8” max). This will give you some preload and ensure the striker is tight enough. It definitely should not be loose, rattling, or able to move around significantly.
sm
Steve M.
By crossbar we’re talking about the front main beam, right?
Yes front beam. Make sure the striker is straight and adjustment nut is not frozen up. On my older Nacra the nut was seized. So it was replaced.
Last two questions:
1) how do we measure/reference the upward bend in the beam?
2) does the lower strap ever “stretch” or need replaced?
Thanks
zenwalrus wrote: Last two questions:
1) how do we measure/reference the upward bend in the beam?
Two ways, stretch a string from end to end, then tighten until the gap at the centre is about 1/8”.
Or, simply tighten the bottom but til it contacts the beam, then turn it up another 1/8”, which would be about two full turns.
E C Hilliard
Nacra 5.7
Bombardier Invitation
How do I tell if the V bar needs replacing? My nylon mast ball is nearly down to the nut.
While you are at also check the mast post area on the main beam for corrosion.
Begin by removing the 3 bolts holding the striker band on each side. On my 5.5, both beam and band where badly corroded, so I built new beams with 100x2mm tubing, with 2mm inserts and stainless band like on the Marstrom Tornado.
As JohnES says, you should also check the mast post area for corrosion.
About your initial question about, go for 10mm/2/8" prebend without mast in place. Easy to adjust, just release the striker rod nut on top of the beam. Then measure striker rod length between band and beam without prebend and adjust it to be 10mm longer.
Edited by revintage on Oct 18, 2020 - 01:16 PM.
I’m still trying to figure out how to post pictures here...As you can see, I need to replace the ball (of course). But, doesn’t the ball look lower than any you’ve seen?
Anyway, the distance between the mast nut and nylon ball is only about 4mm. Every picture I see online has about 20mm or more. Does this mean the strap is stretched? Does the strap stretch? Let’s talk straps here. I’ve been told that they have to be replaced every five years, that they stretch and the sign is the the ball getting closer to the nut because it has to be adjusted, much confusing stuff......
Edited by zenwalrus on Oct 18, 2020 - 03:00 PM.
Click on Site FAQ, top right of page. That will walk you through adding photos. Make an album of your boat.
I find an iPad doesn’t work well
E C Hilliard
Nacra 5.7
Bombardier Invitation
The old Nacra manual is available here: nacrasailing.com/wp-content/uploads/2019/08/nacra-vintage-assembly-manual.pdf
They don't give a prebend measurement, but do say that the dolphin striker strap shouldn't move more than an inch. Current Nacra's use 15mm of prebend, so that might be a good starting point.
Here's a tip; use a good antiseze that DOES NOT have copper in it and is made for marine use. I bought my N20FCS used and the previous owner (AC team) didn't use enough, or the right kind of antiseize, so the threads were damaged to the point that I couldn't tighten or loosen them easily. It's really nice to find out that there's a problem when you hear the striker go "POP!!" while sailing and have no clue what it was until you get back to shore. Luckily, figured it out and added a second nut to get through day two of a regatta. Failure could result in a broken beam(s) and hull damage, so... I replaced it... figured that was cheaper than a new front beam $$$$.