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Old 06-07-2015, 16:39   #31
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Re: mast leaks into bilge- what to address?

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Originally Posted by Patrigo View Post
In reply to Rustic Charm,
It is a keel stepped mast that happens to have a hinged joint in it above where it emerges from the boat. This joint is a solid fixture, obviously, when the four bolts are in the face plates.
Yes, I understand what you have meant. But you have now effectively turned it into a deck stepped mast with the 'stump' now being the compression post to the keel. Not only that, but you have taken the downward pressure of the mast weight and turned it into a shearing action at 45 degrees, which means either this downward pressure is now either deflected towards the bottom cut, either to the bow or the stern, depending on which direction the cut was.

In very small yachts I don't think this would matter, but I think this is wanting in anything of any size, yet alone anything of size caught in heavy winds with main sail up.
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Old 07-07-2015, 05:00   #32
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Re: mast leaks into bilge- what to address?

In reply to Rustic Charm and Cwyckham.
I did not develop this idea, it has been around Fremantle for many years and is present on yachts of all sizes which venture in to the Southern Ocean and Indian Ocean. It was originally figured out by someone who knew what they were doing--hence my adoption of it. I was once hit by a 52 knot (masthead wind speed indicator) hail squall with full sail up with no problems, apart from a lot of bruises. A keel stepped mast is 20% stronger than a deck stepped mast which will fall over if a shroud or stay fails, unless it has lowers, when the top section only will go.
You don't like the idea, fair enough, so go back, to bits of stick, wedges, bits of canvas, pitch and whatever else gives you kicks. Your mast will leak and move, but, what the heck, its traditional, like living in a cave.
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Old 07-07-2015, 10:56   #33
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Re: mast leaks into bilge- what to address?

In Fremantle maybe they smoke grass because definitely the idea is not new, this is by far a deck stepped mast experiment no matter if the plates are bolted at 45 degress or whatever, if i take a deck stepped mast and bolt the step to the mast base its still a deck steeped mast, i dont like the idea by the simple reason that is to complicated,,, even if you loose a lower or upper those bolts are not going to save the day, wedges are a thing of the past, still used this days but lets face it, there is lots of products in the market to make a strong watertight deck collar and forget the wedges , canvas etc,, even the internal mast leaks are a thing of the past if you ask your mast manufacture for a inner plastic dam at deck level, is simple to install next time your drop your mast and keep the wáter at deck level , not in your bilge.... keep in mind that without the continuous run from a keel stepped mast is very hard if not imposible to center and tune your mast foot in relation with the step ,,, saying that all the stress in concentrated in the joint with the bolts,,, if they sail the soutern ocean and cape horn with this thing, could be but is not the ideal solution....
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Old 07-07-2015, 11:58   #34
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Re: mast leaks into bilge- what to address?

Quote:
Originally Posted by Patrigo View Post
In reply to Rustic Charm and Cwyckham.
I did not develop this idea, it has been around Fremantle for many years and is present on yachts of all sizes which venture in to the Southern Ocean and Indian Ocean. It was originally figured out by someone who knew what they were doing--hence my adoption of it. I was once hit by a 52 knot (masthead wind speed indicator) hail squall with full sail up with no problems, apart from a lot of bruises. A keel stepped mast is 20% stronger than a deck stepped mast which will fall over if a shroud or stay fails, unless it has lowers, when the top section only will go.
You don't like the idea, fair enough, so go back, to bits of stick, wedges, bits of canvas, pitch and whatever else gives you kicks. Your mast will leak and move, but, what the heck, its traditional, like living in a cave.
I didn't say I don't like the idea. For your particular situation it sounds ideal... As long as it is properly engineered. Otherwise, it's a very bad idea. That is all.

I'd love to see a source for the 20% stronger claim. There are pros and cons to deck vs keel stepping. Either can be done well or poorly. I actually think a well designed deck stepped mast is probably better, but it's likely a wash in real life.

This is a very thorough post on the subject from a really good thread.
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Old 07-07-2015, 17:06   #35
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mast leaks into bilge- what to address?

While I won't bother to work out the details of the loss of strength and flexibility of the cast section by adding the splice, consider the method used to install the splice.

TIG vs MIG is a big deal when considering an aluminum weld.

Certified TIG welders are in high demand do to the skills required to pass the cert tests. Be assured, a low percentage of certified welders can pass a break test.

MIG welding on the other hand is a much easier process. Setting up the machine and making basic welds can be learned in a short time by the average Joe.

I would bet good money in Vegas that the welding on this modification was done with a MIG and that a number of mast sections were not ruined in testing.

This kind of thing would be easy to test before you ruin an expensive mast. 1" aluminum pipe is cheap. A splice easy to make. If a contoured fulcrum were placed near the splice and pressure applied .........

Break cheaper stuff before making an expensive leap.


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Old 07-07-2015, 18:10   #36
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Re: mast leaks into bilge- what to address?

Quote:
Originally Posted by Patrigo View Post
In reply to Rustic Charm and Cwyckham.
I did not develop this idea, it has been around Fremantle for many years and is present on yachts of all sizes which venture in to the Southern Ocean and Indian Ocean. It was originally figured out by someone who knew what they were doing--hence my adoption of it. I was once hit by a 52 knot (masthead wind speed indicator) hail squall with full sail up with no problems, apart from a lot of bruises. A keel stepped mast is 20% stronger than a deck stepped mast which will fall over if a shroud or stay fails, unless it has lowers, when the top section only will go.
You don't like the idea, fair enough, so go back, to bits of stick, wedges, bits of canvas, pitch and whatever else gives you kicks. Your mast will leak and move, but, what the heck, its traditional, like living in a cave.
Patrigo,

This sounds like a very interesting idea. However, from your description I can not picture how this joint is actually constructed. So, is there any chance you could please send us a set of pictures showing all sides of this joint?

Thank you very much,

Paul
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Old 08-07-2015, 03:16   #37
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Re: mast leaks into bilge- what to address?

It appears to me that my introduction of the jointed keel stepped mast is not being looked at properly.
Engineering wise a deck stepped mast is a compressed beam, failure of any or some parts of the compression (ie. standing rigging) will lead to mast kaput.
Engineering wise a keel stepped mast is a cantilevered beam, failure of any or all of its above deck support (ie. standing rigging) will resullt in a mast which you sure as hell wouldn't hang a sail on, but it stays where it is at.
I didn't work this out, go read up Archimedes, Newton, Bernoulli, Timoshenko, Euler and many more mathematicians and engineers. This idea was engineered by someone who knew his maths and it works. I checked it out, I didn't just attack my yacht with a stick welder and hope for the best.

In reply to Paul, I am not able to get any photos immediately but will do.

Imagine a profile view of a keel stepped mast. About a foot above where it emerges from the vessel it has a cut from the aft of the mast forward at a 45 deg angle down to the front of the mast. Rectangular plates of 1/2 inch aluminium ( okay aluminum for you guys!) slightly wider than the mast and of a length that will allow them to be bolted together external of the mast at the four corners, are welded to each cut face.Four pieces of the same plate are welded vertically to the aft of the mast at an appropriate width, two above and two below the join, so that 1 inch dia holes in each pair overlap at the same level as the plate joint. A 1 inch piece of shaft is put through the four holes and secured so that it cannot fall out. Now we have a hinge, which when the bolts are removed, will allow the mast to be lowered to an appropriate support so that it then can be removed from the boat. The lower section can be made a permanent part of the boat.I took about 2 days to seat my lower section to my complete satisfaction. It beats the hell out of a rush job while a crane is holding the mast and costing you dollars. PVC-- or whatever can be used to carry any mast wiring from top to bottom sections. As I posted earlier it has kept me very happy for 20 years
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Old 08-07-2015, 07:20   #38
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Re: mast leaks into bilge- what to address?

i replaced my mast boots and caulked em, and i made sure the passages water can take to come into boat have been filled with caulk and i am waterfall free.
the boat i sailed gom was a keel stepped seidelmann 37 with a leakage from hell.. mast boot was destroyed, and there is a track down which water pours in a good rainstorm. if you have this set up, put caulk into the track below the gooseneck to keep out unwanted rain ingress.
climb mast and goober all holes someone put into mast to pass wires and halyards. go to masthead and close it off and seal it well.. now mebbe for a year you may have a dry boat.
good luck.
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