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Catalina 25 Specific Forum

best method to drill into mast ???

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77Gypsy
Captain

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USA
356 Posts

Initially Posted - 11/03/2003 : 18:25:38

i need to install my new harken single line reefing, it calls for some holes in the boom and mast. avoiding this as much as possible, i am using my original catalina block mounted on my boom in the exact place the harken one should be mounted. i have no alternative for the mast though. any advice on how to make a hole in the aluminum and then bolt a block there and have it secure enough for the heavy loads.

Steve
78 C25 SR/FK - Gypsy

Edited by - on

Arlyn Stewart
Master Marine Consultant

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USA
2980 Posts

Response Posted - 11/03/2003 : 19:42:05

Steve, cheek blocks and eye straps etc can be attached to the boom or mast in any one of three ways.

<ul><li>drill a hole and use a sheet metal screw </li><li>drill a hole and use a pop rivet </li><li>drill and tap a hole and use a threaded screw </li></ul>

All of which should be coated to prevent galvanic corrosion between the stainless steel fastener and the aluminum spar.

I'm personally not a big fan of sheet metal screws. I like pop rivets. Even 3/16 stainless pop rivets takes a quality tool... above that... a hydraulic tool is needed but most needs on our boats would be limited to 3/16.

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 11/03/2003 : 22:45:04

If you want to tap a hole for a machine screw (bolt), Home Depot (and others) has kits that include the tap and the precise bit for any specific screw diameter and thread size--for a small number of bucks. I agree with Arlyn--that (and pop-rivets, which I haven't used) are better than self-tapping screws.

Now, I'm gonna hafta see why Harken's system involves holes in the mast--I'm still messing with the arrangement of my reefing system, and am wondering about leading the line to the mast (to pull it forward) instead of straight down from the reef tack to the mast base (and then aft).

Edited by - on

Stu Jackson C34
Admiral

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844 Posts

Response Posted - 11/04/2003 : 01:32:26

Dave

I,too, don't understand why any mainsail reefing system needs a hole in the mast.

If it's to turn the line down to the deck to bring aft, that block can be on the side of the boom (cheek block for a line leading aft, or just some kind of fairlead for the tack line to head down), or slipped onto a small piece of material and stuck in the mast slot below the boom.

Any turning block at the base of the mast or mounted on deck can bring the line back to the cockpit.

It could well be that the piece on the mast would be the attachment point for the other end of a single line reefing setup - one end's gotta stay at the forward end of the boom, right?

Maybe Steve'll let us know why (or where) he (or Harken) thinks he has to drill a hole in the mast.

Also, while I agree with the three methods of attachment mentioned above, I've always had good luck with self tapping screws as long as they're only in shear. Pop rivets are hard to get Lanocote to bed to keep the dissimilar metals apart, and "a threads a thread for all 'dat" (in shear, at least). Sure easier to get the Lanocote in. Best way though, I agree, would be to drill and tap.

Stu

Edited by - on

Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 11/04/2003 : 08:53:50

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stu Jackson C34 No. 224 1986
 Pop rivets are hard to get Lanocote to bed to keep the dissimilar metals apart,
<hr height="1" noshade id="quote"></blockquote id="quote">
I love pop rivets. I love stainless steel pop rivets even more. I have always soldered an LED between the rivet and the mast to provide a current path for the electron flow generated by the electrolysis. It is great at night when my mast has Christmas lights all summer long.

Edited by - on

Leon Sisson
Master Marine Consultant

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USA
1893 Posts

Response Posted - 11/04/2003 : 17:07:50

<center> Mounting Hardware To Aluminum Spars </center>

When attaching things to the mast or boom, I prefer to drill and tap for course thread machine screws whenever it's practical to do so. I think there's some rule of thumb about the metal thickness needing to be at least x times the thread pitch, or x% of the fastener diameter, but I'm no mechanical engineer. I really don't like self-tapping threads in this application. Sheet metal screws belong in sheet metal (or wood, unless you're a traditionalist about tapered threads there). As for slowing down dissimilar metal corrosion, I use one of the following for threads: Never-Seez (moly) paste, siicon sealant, or 3M-5200. For mating surfaces: cut up plastic softdrink jugs or boat canvas window material.

<center> Single Line Reefing </center>

In a typical single line reefing setup, one end of the line is terminated on the boom, below or just aft of the reefed clew. The line is then routed up to the reef clew cringle, back down to a cheekblock on the boom aft of the reefed clew, forward along the boom (internal routing or external fairleads optional) to another cheekblock on the boom as close as possible to the gooseneck, up to the reef tack cringle, and back down to something on the side of the mast, just below the gooseneck.

That "something on the side of the mast" depends on whether your control lines are lead aft of not. If not, there's typically a reefing cleat on the side of the mast. If lines are lead aft, the reefing line would likely pass down through a stout fairlead on the mast, down to a turning block at the mast base, out to a deck organizer, and aft to a line clutch.

Wrapping the line around a wench behind the clutch can produce extra tension while reefing. Larger yachts are more likely to be equipped with impressive looking deck wenches, well suited to handling smooth lines without losing control. However, this style of wench can be expensive to maintain, particularly if subjected to harsh conditions and high stress.

-- Leon Sisson

P.S. I see that excerpts from this post quickly made it to Arlyn's bloopers page.

At the risk of sounding pedantic, my entire last paragraph above was deliberately intended to be a tongue in cheek double-entendre. I was aware of the potential high cost of wench maintenance before I ever set foot on the deck of a sailboat.

On a similar note, one of my former girlfriends used to jealously refer to the glass Harken display case at the local ship's store as the "sailboat jewelry counter".

Edited by - Leon Sisson on 11/05/2003 12:41:13

dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 11/04/2003 : 18:18:34

<blockquote id="quote">quote:<hr height="1" noshade id="quote">"Larger yachts are more likely to be equipped with impressive looking deck wenches...However, this style of wench can be expensive to maintain,..."<hr height="1" noshade id="quote"></blockquote id="quote">

Ain't that the truth!

Edited by - dlucier on 11/05/2003 10:40:43

RichardG
Admiral

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USA
990 Posts

Response Posted - 11/04/2003 : 18:59:32

<blockquote id="quote">quote:<hr height="1" noshade id="quote">
--------------------------------------------------------------------------------

quote:
--------------------------------------------------------------------------------
Larger yachts are more likely to be equipped with impressive looking deck wenches
--------------------------------------------------------------------------------

Ain't that the truth!
<hr height="1" noshade id="quote"></blockquote id="quote">

...in which case, bigger isn't necessarily better!

Edited by - RichardG on 11/04/2003 19:01:52

ddlyle
Captain

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302 Posts

Response Posted - 11/05/2003 : 19:57:06

Frank,
I like the idea of LED's to route the stray electrons out, because, like you, I think the Christmas light effect is cool.

But tell me ...
What keeps your LED's from breakin' off

My cheap LEDs work okay until the little wires get bent
one too many times and fall off.
Just like me when I get bent one too many times.

And I'd rather be sailing than replacing LED's and pop rivets.

Edited by - on

MattL
Admiral

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USA
990 Posts

Response Posted - 11/06/2003 : 15:24:31

One thing I didn't see in all the above, excuse me if I just missed it, is a very important step. Before you drill any hole in the mast, mark the location and use a punch to keep the drill from wandering all over the place. If you are adding a cleat or any other device that uses more than one hole you'll have a dificult time of getting things to line up if the holes are even slightly off the mark.

Edited by - on

Champipple
Master Marine Consultant

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USA
6855 Posts

Response Posted - 11/06/2003 : 17:23:15

<blockquote id="quote">quote:<hr height="1" noshade id="quote">I was aware of the potential high cost of wench maintenance before I ever set foot on the deck of a sailboat
<hr height="1" noshade id="quote"></blockquote id="quote">

The new term in these parts is to call them seat covers.....

think about it

Edited by - on

Randolph G. Wilson
1st Mate

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USA
64 Posts

Response Posted - 11/07/2003 : 13:40:14

I am a little concerned by some of the comments re fastening stainless to aluminum using SS screws. I have added several pieces of hardware to my mast and boom using SS screws coated with Locktite.

Can electrolytic corrosion be a serious enough problem to require resetting these? An example would be the pieces used to close the sail slot in the mast. I forgot the gentleman's name that makes thse, but he never mentioned any such problem in mounting them.

Edited by - on

Randolph G. Wilson
1st Mate

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USA
64 Posts

Response Posted - 11/07/2003 : 13:41:51

Edited by - on

Stu Jackson C34
Admiral

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844 Posts

Response Posted - 11/09/2003 : 23:15:03

Randolph

Jim or Joe, I forget, but a great guy who made the mast gates.

Heck, HE shouldn't have to warn you, not a reason for a lawsuit against a guy who does great work.

If and when you mix metals YOU need to take care, not someone who sells you the stuff.

Stu

Edited by - on

Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 11/10/2003 : 09:37:34

You are right, we are responsible for our boats. Even when a boatyard does work for you you should make your expectations and requirements clear. Sometimes I think we little boat sailors lke to talk about big boat stuff just to play like we are in the game. I doubt electrolysis is an issue for the majority of us. At least as a puddle pounder I don't think it is for us. If I had a 40 year old Alberg in the tropics maybe I would be concerned but I have never seen any sign of electrolysis on any lake boat.

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