Just going over my new 5.2 and first job is to make the mast watertight. I presume the hole going thru near the base of the mast is where the mast rotator used to be mounted, and someone has moved it to the newer location above the boom mount, or would it be for anything else? Obviously I want to block the hole if possible.
Also how do you ensure that water does not get into the mast where the bolt currently passes thru to hold the mast rotator in place, if the mast was underwater I can imagine water would trickle into the mast thru that fitting and be a pain to get back out?
I will probably remove a lot of the mast fittings and refit them with new sealant as they have a lot of old sealant smeared all over them; anyone know what size rivets most of them used so I can order some in, I am presuming 3/16 monel, anyone know what length they would typically be?
I am missing the pin that goes thru the mast base to hold it onto the ball whilst raising it, is that a special part or a generic dinghy fitting / pin (not many places around here to get an offcut of stainless bar so need to order something that fits).
Thanks, cant wait to get her up and running and got try her
When flipped your Nacra mast will only be in the water about to the mast hound. Of course if you turtle the boat every inch of the mast is under water. The mast head will have appx 14-15psi trying to push in, less as you move towards the water surface.
I just used marine sealant,(basically any adhesive sealant from DOW or 3M) to seal that hole.(I removed rotator from one boat). I only sealed one, & push/twist a piece of rubber plug in the other. It can be pulled out to drain any water that does get in.
Before I went to the work of removing all the fittings, why not test it first?
Plug those bottom holes with some rubber plugs, then flip the boat, or toss the mast in the lake & stand on it, or otherwise weight it so it sinks 5-10 ft. I say sink it because a fitting may be OK while floating on the surface, but leak under pressure. If you turtle the boat the masthead is now 29' down, which equates to almost 1 atmosphere, close to 14psi in your case. Leave it there for 1/2 hour to simulate flipping & righting problem. Tip it up & remove the plugs at the bottom, if you get none or very little water, don't waste your time fixing a non existent problem.
I "sealed" the through bolt by using a 3/4"diameter rubber washer & thin SS washer on each side. You need to find rubber washers with a 1/4" hole, they can be stretched over the 5/16" bolt giving a fairly tight fit. Initially, the rotator arm would ruin the thin washer as it rotated up & down. I solved this by coating both sides of the washer with vaseline, then adding a thin SS washer between the rotator arm & the washer. You need to snug the bolt up just enough to apply a bit of pressure, forcing the SS washer slightly against the rubber washer. I turtled the 5.7 once last year & it worked, though it was not under for very long.
I have used a short screwdriver, a 1/4" bolt, a 6" landing gear safety lock pin from a jet, & even the actual pin. The cheapest,(and it works just as well as the real pin) is a 1/4" SS bolt.
The real pin has a hole drilled in it so it can be attached to the mast, ensuring you have it handy when you need it.
The downside of the bolt, is you have to remember to rotate the mast the correct way when you bring it down. IF you go the other way, you cannot remove the bolt. In this photo I turned the mast the wrong way. I didn't have any help, I went to the garage & got the bolt cutters.
-- 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 used this product to fill some voids in the masthead casting on my Super Cat15. It worked great. I then primed the inside of the casting and mating surface with that green zinc chromate out drive primer. I bed down my fittings with 3M 5200. My mast is water tight with positive pressure.GH
Thanks for all the info, seeing how bad it is before ripping it all apart id probably a very good idea, I tend to make a career out of even the smallest jobs!
I was contemplating rubber washers on that thru bolt, nice tip about the stainless washers, will work on that, and like the idea of keeping one hole as a drain hole.
That Super Alloy 1 looks amazing; I did try something similar once before on an aluminium fuel tank and could not get the alloy close to hot enough with a propane torch so suspect the mast will be the same unless I can borrow an oxy, I might just go with some filler or rivet a plate over it for now.
Ha ha, that pic says it all, top tip! I found Murrays have the pin for $7 so will add it to my order of a few other bits.
That alloy melts at a really low temp. I was using it on a casting, however. It could be tough to get a large extrusion hot enough given the heat sink effect. I had a lot of extra holes in my front crossbeam on the SC 15. They were leftover from a previous owners attempt to replace the mast step. I had a buddy at work close them all up with a MIG welder. That worked out well, but the guy on the welder needed a light touch.
If you're getting that detailed, you could install a sleeve through the mast where the rotator bolts on. With that sealed in water ingress would not be a problem there.
If your going with pop rivets you're going to need a hell of a pop rivet gun. I use 3/16 SS sometimes and it's all my Craftsman heavy duty can handle. The factory guys at Super Cat don't like pop rivets and recommend the drill and tap method.
When I sealed my mast head casting and mast hound I tilted the mast head down and filled it with water. That proved to be a good test for water tightness on those fittings. That wouldn't work for all the fittings at once unless you had vent holes you could seal up. You could also consider the compressed air method. Seal it all up except for one drain hole at the bottom and put in a schrader valve. Pump it up and check it with a tire gauge and soapy water around the fittings.
I can state from experience that it doesn't take much water in the mast to make righting a capsize difficult. Getting your mast airtight it well worth the effort.
Good luck with it all, GH
Edited by gahamby on Aug 28, 2013 - 09:08 AM.
-- '82 Super Cat 15
Hull #315
Virginia
Previously owned: '70 H14, '79 H16, '68 Sailmaster 26, '85 H14T --
You could do that, BUT, you would have to remove the mast base. That hole goes through the base. The bse casting is not a polished finish, you would have to carve the sleeve to generally fit the contours, then TIG it in place.
-- 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 was referring to the current mast rotator bolt that's about 18" up from the mast base. That sleeve could be sealed in with epoxy or 5200. You could also MIG it in and grind it flat. Sealing up the old hole at the mast base has been discussed already. I would remove the mast base in any event and do some serious clean up inside and out.
-- '82 Super Cat 15
Hull #315
Virginia
Previously owned: '70 H14, '79 H16, '68 Sailmaster 26, '85 H14T --
Agreed, but having the parts and plan together now is a good idea. The OP is soliciting ideas and opinions on how to proceed. How would you repair that mast this winter? GH
-- '82 Super Cat 15
Hull #315
Virginia
Previously owned: '70 H14, '79 H16, '68 Sailmaster 26, '85 H14T --
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