Just purchased a 1983 and want to replace the curved dolphin striker. Poor dolphin..... Anyone ever try to upgrade to the later model - 9/16" vs. 1/2"? Doing the math, the new part is over 50% "stronger". I understand there are a few holes to enlarge-not to mention the increased ball diameter. It stands to reason this change was made for good reason.

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Mark Hirte
Nacra 5.0 1983 - (1st cat)
Deerfield, Il
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mhirte

Just purchased a 1983 and want to replace the curved dolphin striker.

Hi mhirte, welcome to TheBeachcats.com.

Did you mean bent dolphin striker post? We have plenty of Nacra experts here so I'm sure they will chime in with info about the upgraded post.

In the mean time you can check this topic about mast bases.
http://www.thebeachcats.c…ms/viewtopic/topic/12662

I would suspect if you go with a bigger ball you have to have a different mast base as well, but wait for the experts.

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Damon Linkous
1992 Hobie 18
Memphis, TN

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have a look at these albums in Tech Tips
http://www.thebeachcats.c…ictures/?g2_itemId=87292
http://www.thebeachcats.c…ictures/?g2_itemId=73301
IIRC, the 1/2" rods also used a smaller V brace bar.
You would need the upgraded one of those, (fairly easy to source, I have several, Pete Begle or Dan Berger may also have them, depending on where you are in the country) + the DS casting,(saddle) that sits on the V brace, that the DS rod sits on. You can see it in photo 3 of the 2nd album. Here are all of the parts. Murrays sells a kit with everything you need, make sure it includes the compression tube.
http://www.murrays.com/01-8002.html
http://www.murrays.com/C-NF.html
You would also need the DS rod, ball, 2 SS nuts, 2 large washers, new mast base & the compression tube that sits inside the beam,(the rod goes through it, prevents beam from being collapsed).
It's a bit of change, if you have to buy all the parts new. Look for used, but not corroded to hell.
You would need to redrill the 2 holes through the beam, I would get it done using a drill press, it is damned hard to drill to holes in perfect alignment, doing it one at a time with a hand held drill.
Does your boat have the half moon chocks inside the ends of the beam? They prevent the beam from rotating. I have seen some earlier models that didn't use it. Many have drilled 2 holes in each bean strap & installed an SS rivet, does the same thing.

Go through the Tech Albums, & Members Albums, there are quite a few 5.0 people here.
Here is a Nacra diagram of the 500 front beam,(I can't find the link to the older Nacra Parts Manual, can anyone post the link?), don't worry about the beam being a different profile, the assembly of the DS is the same with the exception of part shown as #31300. On the older boats it is a tube that sits vertically.
I have all the parts, however, I think I'll hold onto my only spare base, just in case i wreck one!



Edited by Edchris177 on Apr 16, 2014 - 09:10 PM.

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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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Damon, Thanks for the forum info and the links.
Ed, The information that the V brace needs to be replaced is enough to make me just do a simple replacement of the 1/2" shaft for now. Thank you for those links. The boat does have the half moon chocks, which seems a nice design solution. Hull design is what drew me to this boat and I am finding lots of other good things now that is entirely disassembled.

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Mark Hirte
Nacra 5.0 1983 - (1st cat)
Deerfield, Il
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The only cat I had with the 1/2" rod was an old 5.2 that had a hull explode. Look in Tech tips for the album showing the "inside of early Nacra hulls."
One thing that might be workable if you don't want to change the strap, is to get a 9/16" DS rod, & have any shop turn down the bottom 1/2" to 1/2" diameter, so it would fit into the existing divot on the saddle. You would have to change the mast base & ball. $229 for the kit, or source used parts for half of that.
The 5.0 is a great solo boat. We drive it pretty hard up here on Lake Simcoe, can get pretty rough in a south wind. I have pitchpoled it on a broad reach in 20 mph, but you really have to work at it.
It is about the same to right as the larger 5.7. If the wind is about 18mph my skinny 170lbs can do it solo, less than that i need the help of a bag.
We keep it mast up, fully rigged all season, the only thing is to get the main from the garage & hoist it. It is an '88, picked it up from Glencoe Beach near Chicago.
Roller furling was a huge help. Let me know if you need any help with the rudders. Some people despise them, but if you understand them & do it right, they are fine,(hopefully you have the pivmatics if you have shoals).

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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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Don't let the 'V' brace scare you, they are a piece of cake to make. Simply purchase some aluminum flat stock bar (I think 1/4" thick by 1 1/4" wide but will have to check), put in a vise and start hitting with a rubber mallet. You can use your old for a template. I've done 3 so far in my restorations. I start with the center bend, then the tips. Leave a little extra on the end and cut to length after the bend. It probably take less then 30 minutes from bending start to bolting it back on.

Hand drilling the crossbeam is not a problem since you are only enlarging the existing holes. Get a unibit (step drill) and step it to the correct diameter. The unibit will make nice round holes in thin stock whereas a regular bit will make an oval. Make sure you get a bit that has a step for the hole size you require. There are some with very small steps, avoid those as the steps are too short and you can't get through material without starting to hit the next step on the bit, thus enlarging the hole on the outside just a bit.

Hand drilling a new crossbeam is not a problem either if you don't have a press. In fact, unless you have a jig to hold the crossbeam perfect, I'd hand drill. Simply make a line around the crossbeam that is square all the way around, hold the crossbeam on a flat even surface and use a micrometer or other accurate means to measure up 2" on both sides. Roll it 180 degrees and double check your measurements. Drill with a unibit drill rather than a regular drill bit after you make a pilot hole with a regular bit.

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Craig
Windrider Rave Hydrofoil
Nacra 5.2 Restored and heavily modified
Nacra 5.2 (one under restoration)
Nacra 5.7
Nacra 5.8NA
SoCal
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Edchris177- In an effort to get the boat water ready quickly I'm going to simply replace the stock rod. It is interesting that your boat came from Glencoe beach as that is where this 1983 5.0 is going to reside. I am late to the sailing party as I first got on a Sunfish at age 57 and now have my first cat at 60. The folks at Glencoe beach have lured me into their addiction by letting me sail on their boats. Wish I had done this 40 years ago!
This boat doesn't have roller furling, but I think that will be an eventual upgrade.
nacraflyer- Great information here. As mentioned, I'm already headed down the simple replacement path or I'd go homemade per your directions. (Hopefully, that won't be necessary for awhile.) What you describe for the crossbar must be pretty close to the production version as these are pretty low production volume large parts. There might have been a wooden fixture involved. I agree with you about the step drill for sheet metal - well worth it.

Thanks for the useful advise.

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Mark Hirte
Nacra 5.0 1983 - (1st cat)
Deerfield, Il
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Quote

This boat doesn't have roller furling, but I think that will be an eventual upgrade.

Keep your eye out for a used furler & drum.
Glencoe is a pretty upscale neighborhood, with good facilities. You won't really need the furler, you will have a good beach to launch & recover from.
I think all the Cat fleet there keeps their sails in lockers, when we picked up our 5.0 the owner got the sails, blocks etc from his locker.
IF you can source or share a set of Cat Trax will be of help.
One other item, hull plugs. It is fine to loosen them when leaving the boat, but I would not remove them. The previous owner did, & I washed 5lb of sand out of each hull. I ended up tilting the boat up, then inserting a long copper tube into the hull,( a bit of work to get it through the bulkhead drains), then blasting water up while rocking the hulls. It was surprising how much sand had been blown in.

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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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