Mast pivoting setup

[Geshka]

Hello everybody.

I am working on mast pivoting solution - currently there is none, so it makes process of rising and lowering mast a great hassle.

Here is current setup:
Mast bottom edge has a wooden plug



It has plate with pin (knuckle) that supported with bigger plate with corresponding hole attached to the deck.



As you can see both parth are not connected to each other on any way, so it is a problem.

For making a hinge, I fabricated a U shape supporting bracket and it suppose to be cross-pin in the bottom of the mast.



I will drill corresponding holes later.

Here is my question - will this U-shape bracket (hinge) alone hold the mast secure enough or I need to leave original support knuckle-hole plates as well ?

Thanks a lot
Gene.

[wizbang 13]

Is the mast "hinge" the pin that will go through?
That should hold it, but,
I cannot speak to the ability of the "u shape bracket" to carry the force of the spar while it is half up or half down. Or, if the alloy spar itself, can be supported, or more accurately, un supported, while laying at 45 degrees or less.
Dunno how tall or heavy the spar is, dunno what rigging the spar carries.

[Ian McColgin]

Honestly it looks about half way from an actual hinge to an actual tabernacle without the clear benefits of either.

A major issue to solve is the thrust caused by the stays' tension. A pin though the mast will either bend or will elongate its hole under that strain. The "easiest" solution might be to put a hing at the aft end of the rectangular plate and maybe three framing pieces - sides and forward - so the mast can be tipped up.

For raising, you'll want something to push the mast up to at least 45 degrees, from whence you can haul it up the rest of the way on the jib halyard or just by pushing it up with your shoulder till the mast catches up on the back stay. Shroud placement is critical, usually swept back just a hair so they can stay slack till the mast is upright.

[Geshka]

Thanks for the answer wizbang13.
Yes, hinge is suppose to be a pin going through the mast, mast yet to be drilled somewhere near the bottom.

Spar is not going to be left in 45 degrees - if I understood you correctly - it is either fully erected or down and I don't have any type of support while rising it or lowering. Is that suppose to be an issue ?

[Jay Greer]

Raising a mast can be made easier if one rigs a spar such as a spinaker pole on the face of the mast. The pole will need a topping lift. Two after guys are rigged on both sides of the deck to keep the pole on center as a down haul is hauled on from the tip of the pole. This is an aid for a mast that is just a bit unwieldy to get started off the deck and aids in getting it raised enough to allow a higher purchase from a halyard to come into mechanical advantage.
Jay

[Ian McColgin]

The actual raising depends on the weight of the mast. This one looks small. Any mast that you can lift alone is most easily pushed most of the way up. Masts up to 25 feet or so once laid in the hing with a bit less than half hanging out past the transom will likely leave the center of balance ahead of the transom so if you stand in the cockpit, you can get under the mast and pick it up so it's on your shoulder or held up by your hands over your head. You just walk forward pushing the mast more and more verticle till it catches up on the backstay and shrouds. Then you trim the jack line that you'd laid out to the head stay and through the stem fitting while leaning on the mast, and lastly move to the bow to pin the stay.

The system Jay mentioned does the whole lift, or most of it, on something running from the masthead or there abouts. On bigger boats with heavy masts the strut you need might be a spinnaker pole with a little adaptation, but the longer the better. It fits against the mast down by the pivot and gives a bit of angle for your hauling line.

Either way but especially the latter there is enormous strain on the pivot pushing mostly forward at first. The whole bit needs to be quite strong to withstand the thrust.

Take a look around some boat yards. Hinged mast steps are quite common and you should get some notions of how to do this. Maybe find some catamaran sailors or such who do a lot of sailing off trailors.

By the way, what boat and how big the mast? How heavy?

G'luck.

[JimD]

You can buy a proper mast step for $32 from Glen-L http://www.boatdesigns.com/Pivoting-...ctinfo/03-063/ . I have one though am not presently using it. the weight of the mast is not supported by the pin. When the mast is up it sits on the step. This is done by making the hole in either the mast or the step slightly oblong. Don't know if the one shown would fit your mast, of course.

[Geshka]

Take a look around some boat yards. Hinged mast steps are quite common and you should get some notions of how to do this. Maybe find some catamaran sailors or such who do a lot of sailing off trailors.

By the way, what boat and how big the mast? How heavy?

G'luck.

Thanks Ian.
Boat is Y-Flyer, mast is about 22 feet ( I need to measure it exactly ) .
BTW. I started blog about restoring this boat http://casualcitizen.blogspot.ca/

Everybody is welcomed to visit and leave you note.

Gene.

[Geshka]

the weight of the mast is not supported by the pin. When the mast is up it sits on the step. This is done by making the hole in either the mast or the step slightly oblong.

Thanks, I will do the same way - pivoting bracket will support mast during rising/lowering; other time it will be supported with pin step.

Gene.

[jackster]

Maybe I'm wrong but it doesn't look to me that that arrangement is meant to be on a tabernacle.
It is to allow the mast to pivot... that is twist... not raise or lower. Yes?

Seems in order to change it to allow it to raise and lower the mast, your tabernacle will need a pivot 5 or 6 inches Aft of the mast to let the pivot pin clear.
A tricky bit of precise rigging and fabrication, IMHO.

[wizbang 13]

yup, now we see it is an old racing scow. tired to boot. welcome to the tired old race boat club.
Find out how it was raised and lowered in the old days.

[Canoe]

Hi Gene,

the tabernackles we use here in Germany often have an angled baseplate to enable the (allso angled) mast to just rest on the baseplate when upright, when lowering the mast the foot of the mast clears the baseplate so no oblong holes are needed. Our 30 year old Jollenkreuzer did`nt even have any stengthning arround the holes in the alloy mast and showed no undue wear after all those years of use.

To ease the lifting/lowering process we use the spi pole as a "Jutbaum"

Hope that helps ( please don`t ask me to post pics. as I have none! ).

Alan

[Peerie Maa]

Thanks, I will do the same way - pivoting bracket will support mast during rising/lowering; other time it will be supported with pin step.

Gene.

That'll not work, you cannot have a hinge pin and the pin in the existing step. It may be too late now but I would have fabricated a hinge behind the mast attaching the plate with the pin in it to the plate with the hole on the deck.