Sealing Straight Through Spreader Idea :: Catamaran Sailboats at TheBeachcats.com

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Sealing Straight Through Spreader Idea

szicree

Rank: Lubber

Registered: May 02, 2017

Last visit: Aug 06, 2017

Posts: 13
Posted: May 23, 2017 - 10:56 PM

Hi,
I'm new to the forum and also new to my '83 Nacra 5.0. I was a little surprised to see the way the spreader passes right through the mast and I learned on here that there were originally some sort of rubber washers to provide sealing (sure). Today I set out to hopefully seal things up in a different way. Here's a picture before doing anything.

I carefully cut a piece of 1" pvc to fit inside the mast at the hole. By "inside" I mean that the piece had to be slid into position by first removing the mast base. This was ok, since I was resealing it anyway. I chose 1" on purpose because the i.d. is about 1/4" bigger than the hole in the mast.

Once I got everything in place, it was surprisingly easy to slather on a healthy bead of 5200 to the inside of the pipe where it meets the mast. The hole is actually big enough to get your finger in there and create a nice fillet.

My apologies if this is an old idea.

Regards,
Steve Zicree

Edited by szicree on May 24, 2017 - 08:06 PM.
dmgbear55

Rank: Mate

Registered: Jun 22, 2015

Last visit: Jul 06, 2018

Posts: 258
Posted: May 24, 2017 - 01:05 AM

My 1976 Nacra 5.2 has the round spreaders too. I do some minor silicone around the large washers to keep some water out, but the main thing is to make sure the very top end of the mast is sealed. Unless something goes horribly wrong Nacra's are not real inclined to go turtle. Because of the way the spreader is loaded from opposite sides it will always want to shift around and breakor stretch any seal. Then as a fall back I also have a small hole at the base of the mast that is covered with an aluminum tape. If the mast gains any water from condensation (this is the biggest problem), rain or a wicked bad crash I can pierce the hole in the tape and slowly drain the mast out.

Here is a video I did last summer when I was rebuilding my boat and I was putting the mast back together.

https://www.youtube.com/watch?v=dMqKhR1qNyY&t=12s

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dg
NACRA 5.2 #400
This End Up
Original owner since 1975
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szicree

Rank: Lubber

Registered: May 02, 2017

Last visit: Aug 06, 2017

Posts: 13
Posted: May 24, 2017 - 05:57 PM

DG,
I agree that the spreader sliding back and forth will break any seal, but my approach removes this concern completely.

On a related note, does anybody have a definitive source on diamond wire tension numbers for this type of spreader? The "push it against the mast at 12 inches" seems a bit subjective.

Steve Zicree
Edchris177

Rank: Chief

Registered: Nov 26, 2009

Last visit: Aug 10, 2024

Posts: 2531
Posted: May 24, 2017 - 07:23 PM

Quote I have pictures, but don't know how to attach. My apologies if this is an old idea.

Click on SITE FAQ, near the top of the page. Make an album to document your project, then add your photos tot he album.
As Bear said, Nacras are not real inclined to turtle, BUT, if you sail in high wind, when the boat flips, the wind pushing on the tramp wants to drive the sail under, & it will go turtle. They come back onto their side very easy, just by standing on the bow & leaning on the righting line.
Any amount of water in the mast will make it very hard to right. Both the 5.0 & 5.7 float on their sides with the mast about 1/3 in the water.

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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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szicree

Rank: Lubber

Registered: May 02, 2017

Last visit: Aug 06, 2017

Posts: 13
Posted: May 24, 2017 - 10:19 PM

Ed,
Thanks for the assist on the pics. I agree that turtling is unlikely, but if that mast fills with water, I don't think it's coming back up.

Steve Zicree
dmgbear55

Rank: Mate

Registered: Jun 22, 2015

Last visit: Jul 06, 2018

Posts: 258
Posted: May 25, 2017 - 02:40 AM

Diamond wire tension is relative to the shape of the main that you are trying to achieve and relative to the general wind conditions you sail in. If you sail more often in heavier wind conditions you might want a flatter main and so would have the diamond wires loose, so the mast can bend more to flatten the main out. If you sail in lighter air, or maybe with heavy crew weight you may want the main to be more full, so tighter will power up the main. Then add in mast rotation and the way that changes mast bend and now you are into the fun part of these boats. The 12" mast touching thing is just a starting point. I used to get beat by guys that had the diamond wires so loose I thought the damn mast would break and maybe it did on a different day. They just knew their boats, their crews and the conditions that day and made better choices. Me on the other hand, I just set the dang things drank too much beer the night before and didn't think about it too much until it was all over.

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dg
NACRA 5.2 #400
This End Up
Original owner since 1975
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