There are two other forum threads here having to do with mast base replacements, but I didn't want to hijack those. So, I am replacing my NACRA5.2 base and dolphin rod with the group of parts I bought from Murrays. Thanks to those for the guidance in removing the rivets to get the old mast base out. Now I've got two new issues.
Issue 1. The new rod is more than an inch longer than the old one: Am I to cut this new rod down in length to match the old one? Or is my mast just going to sit an inch+ higher than before?
Issue 2. The new mast base leaves sizeable holes in the bottom of the mast. This was fully covered by the old mast base. Is this going to be an issue? It's at the bottom, so water should really get in there much, but if I end up turtled, isn't this going to let a lot of water down into my mast?
1# When I did the replacement job I ran across the same issues. I felt that having the rob extending the full length would potentially provide the opportunity for the rod to bend if under heavy loading, I understand the loading on the mast is supposed to be straight down but stuff happens. I fooled around with it for a while and ended up cutting off about an 1" to 1 1/4" I don't recall exactly. It still makes me nervous having it extending as much as it does but so far no problems.
2# Caulk ! lots of it. I put a healthy amount all around the new base before installing and in the voids where the new base sail slot did not match up well. I did clean it all off the outside after the new base was re-riveted back in place.
I don't remember rotating the mast before the new mast base and larger ball but if you forget to rotate the mast coming down with the new style base the mast WILL pop off the ball and come crashing down even with the pin in.
Don't ask how I know this.
Good luck
kswenor where do you sail out of?
-- Jeff O
N5.0
solcat 18(sold),
N5.2,
H16
Camarillo CA --
Personally 1" longer on the rod wouldn't bother me, though as Jeff says, it does give slightly more leverage, but the difference is very small. I have 4,(five counting the one I bent) DS rods from Nacra 5.0, 5.2, & 5.7 they are all slightly different lengths. I also have, I think 5, of the V brace straps the DS rod sits on, they range from 70" to 73". What this means is that when you bend them to line up with the 3 bolt holes at each end of the beam, the depth of the "V" is different depths, thereby using different length DS rods, or having the same rod sit higher or lower.
Regarding Issue #2 Here is a thread on the different bases used, & the holes left exposed; http://www.thebeachcats.c…ms/viewtopic/topic/12662
Disregard my first post, I was confused as to what bh3700 was talking about.
I'm not sure the different bases correspond to certain years. My 5.7 (1984) the base covers all holes in the mast extrusion. The newer 5.0 (1988) shows those two little triangles,(possibly the base was changed?). They have been filled with sealant, & I have seen this done on other mast bases, squirt some marine sealant in there & start sailing.
YES! seal them, if you turtle & get even a gallon of water at the end of a 30' stick, that is huge moment to try & move past horizontal.
-- 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 --
I just replaced mine today too. You can cut through the stainless rod cleanly with a 4 1/2 angle grinder and a metal cur off wheel from Ace for 4.00. I just clamped it in a vise with a 2x4 scrap on either side. I even chamford the edge a bit. You can cur down to about 1/8 inch pretty accurately. I left mine a 1/4 longer and just adjusted the chain plates.
Yes, they cut very easily with a cutoff wheel. If you don't have one, a hacksaw works fine, the material is only 304 SS, harder than re-bar, but not like cutting something with chrome in it.
As nhanson says, try to use something as a guide to get a "square cut", then use a b.ast.ard mill file, or grinder to chamfer the edges , just a bit.
Hacksaws tend to wander, you don't want the end cut to be on an odd angle.
Edited by Edchris177 on May 25, 2012 - 09:13 PM.
-- 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 --
To do this job right you're going to need to do a few things. I don’t know what the instructions are telling you but this is pretty much what I was instructed to do when I had a main beam failure do to corrosion at the mast post on a 5.8
First off I would not cut the rod. I believe the new mast base has a longer shoulders and you may need this clearance. When everything is a part inspect the main beam for corrosion around the mast post. If there is daylight between the hole and the road start shopping for a new beam. No sense on doing all this work if you’re only gong to do it again later.
Most important, take the main beam OFF THE BOAT, or loosen it up to where there is daylight between the beam and the hulls. Get the new rod in with the compression sleeve. Very important make sure you use either anti-seize or Teflon paste where ever the stainless is touching the aluminum and don’t be stingy about it.. I know the Teflon is expensive that is why I use the anti-seize. Get everything in and tighten up the bottom bolt and keep going until you have ¼ inch of pre-bend in the beam. Once this is all done reassemble everything..
Good luck
Not to put to fine a point on things, John, but isn't the Nacra prebend setting 3/8"?
I would also leave the extra inch, you will just need to move the shrouds up 1 hole.
-- 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 --
Thanks for the responses guys. I've got to believe that at least a little bit needs to be taken off the rod, as I am gathering that this kit wasn't made 5.2 specific, but rather to accommodate the larger nacras also. Good point about the larger shoulders on the new base though. I'll do some measuring and figuring before I make any cuts. Measure twice cut once!
JohnES, I'm not noticing any corrosion evidence as of yet, thank goodness, I'm not in the mood to go looking for a new front beam. The instructions mention the anti-seize numerouse times so I took the hint and picked some up. The instructions also mention 1/2" of pre-bend, but once again I'm thinking this was for a 5.8 or something larger my 5.2. I'll roll w the 3/8".
One thing the directions don't go very far into describing is getting the new compression sleeve into the front beam. Do I need to slide it in w a pipe or something and somehow line it up w the rod holes? Or am I supposed to open up the top rod hole enough w a file to be able to fit it in?
And now that we've mentioned the front beam enough times, I'd like to take out my middle brace that attaches between the fore and aft beams. I've read before that I then need to keep the beams from rotating somehow. Have any of you done this before? Would two rivets through each strap be enough you think? That would be a total of 8 fasteners on each beam.
ohmsj, I sail mostly on Lake Lewisville in TX, but I've trailer plenty of other places as I like to explore. Even trailered her up through Iowa and back down through Michigan. I got skunked for wind on lake Michigan, go figure, but being out on the big lake was a thrill in itself. I'll make it up there again for sure.
Use a piece of pvc or equal pipe and tape the tube on the end. Slide the tube in the beam and run bolt thru. Then pull out pipe (tape will give way). Make sure spacer tube fit nice inside tube. The beam might be distorted at the ends from the beam straps so make sure you loosen them. you might have to enter the beam horizontally here and then rotate it once inside. Be patient this can be a pain in the you know what. You can shave it down a little if needed and shape the ends to match the beam.
I removed the center tube on my older 5.2 and purchased the same Casting used on the new Nacras at the ends of the front beam. I ran a thru bolt angled to the aft of the hull to clear the bulk head and used a stainless steel bolt,washer and lock nut. Silicone on inside of hull between washer and hull. Even though the fiberglass is not that thick here it is fine for the rotational movement you are trying to stop. Make sure to properly torque your beam strap bolts (16-18ft/lbs) and don't let the aluminum square washers twist when tightening. Tighten the internal bolt last. If you feel the bolts are not tightening correctly just thru bolt them.The stress on the straps are greater at the rear beam. I have already had to thru bolt 3 locations on my 5.5. Drill out rivets form old center castings and your good to go. I would not drill and rivet thru the beam straps. This would change the strength of them and the load path they are deigned to handle.
Good luck
-- David
Nacra 5.5SL
Nacra 5.2 (sold)
San Diego, CA --
If you decide to cut off some thread... Put a nut on and use it as a guide below the cut. Then you take off the nut after the cutting and it will align the threads like a die and make it easier to start nuts after the cut.
-- Hal Liske
Livermore CA
H 16 (6+ 1.. Friends) H 3.2 N 5.2 (2) H 17 (2) H-18
Nacra 5.8 (son's) H 20 (Friends)
It's a Sickness
So I cut off about 3/4" of the non-threaded end and I'm liking how its looking so far. I'm taking out my center tramp tube and that worked perfectly to tape the new dolphin striker rod sleeve to and get it into place to but the rod through, great suggestion there, thanks davidsd. Predicate all the help guys.
