I replaced the bent dolphin striker rod but I can not find any reference to how tightly it should be install against the support tang. I seems like it would be pretty critical..
Jon

The dolphin striker V bar (suport tang)should have less 1/4 inch of play when you press on the center of each side.

I once read somewhere about stretching a masons line from end to end of the DS rod, then turning the nut to bend the rod upwards,(preload the beam) a certain amount.
MUMMP told me to just turn the nut til it makes contact with the beam, then turn it upwards another 3/8", that's what I did. I have pictures & a write up in the technical help section.
As HULLFLYER suggests, more than a 1/4" play is to much, here is the reference from the NACRA assembly manual.

"12. Periodically, check the dolphin striker strap tension. It should not move more than 1/4."

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Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
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. . . to add, the 3/8" pre-bend is a factory spec.

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Philip
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Looked at your tech help pics, and I wanted to comment on them. Cutting through the rod with a hacksaw takes about 2 minutes. Certainly nothing to avoid, especially if you have your boat in a location without A/C or a compressor.

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Rob
OKC
Pile of Nacra parts..
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Cutting through the rod with a hacksaw takes about 2 minutes. Certainly nothing to avoid, especially if you have your boat in a location without A/C or a compressor.

Take even less time with a sawzall! I agree. Fastest way to remove the old rod is to cut it away. When I did mine, I turned it down till it contacted the beam and then a quarter turn more.

When I did mine I used an angle grinder with a cutoff wheel to get the old dolphinstriker off. Hacksaw with a NEW blade will work just as well and you wont have to worry about detempering the steel. A used hacksaw blade may not work on the hardened stainless.

Make sure you grease the threads or they could gall (they did for me but I overtightened them. I agree with Larry tighten to the beam and them go another half turn to full turn and no more. If you overtighten you will certainly strip the threads.

D.

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Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
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You are right, don't shy from using a hacksaw if need be, 304 SS is not much harder than normal cold rolled steel.
I had the boat totally apart after I bought it at the beginning of winter, so the parts were inside with access to power tools. My rod was bent above & below the beam, so had to be cut in two places to remove. I have two angle grinders, one with grinding wheel & one with cutoff,(a necessity when building more docks!)so that's what I used.
Dave I wouldn't worry about changing the temper, if you are cutting the rod, it is now scrap. I think you had a bad thread or nut if you stripped it that easy. I tried to get the top nut off, I used a 12" wrench with a piece of pipe on the end as a cheater. I applied almost 200 ft lb before it stripped the threads & I had to make a second cut to get the rod out. Setting the preload to 3/8" was only about 10-15 ft lbs, no lube used.

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Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
--

Yeah I misspoke there, I meant to be worried about detempering the nuts if you are going to reuse them. Not a huge concern really and you are probably right about the bad threads. Better safe than sorry though, I've had too many stainless and titanium pieces cold weld under pressure so I use grease on all my connections. I didn't earlier this year when replacing my dolphin striker just because i was lazy and didn't have any readily available.

D.

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Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
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I meant to be worried about detempering the nuts if you are going to reuse them.

Yes, that is worth remembering. It can be hard to find that size in nylock. I fried the nylock insert in one of the nuts as I had to cut quite close to it. It is easy to find 9/16 SS nuts, fine thread, but if you can't get aircraft lock nuts you either have to double nut,(looks ugly)or use lock washers.
Murrays has them for a few bucks each, but shipping up here is $30. That is my one gripe with Murrays, US Post will send that stuff here for a buck or two.

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Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
--

Quote

Setting the preload to 3/8" was only about 10-15 ft lbs, no lube used.

One lesson learned from past maintenance and my dealer. Nothing on these boats is meant to be torqued more than the low end of this quoted range. Thus a good torque wrench and thread lube are musts. I had learned my lesson and did not overtorque this bit but previously I had to redrill / retap two of my strap bolts. So if you find yourself applying the elbow grease, back off. Think a tad more than finger tight is what my dealer told me.