Raising a Keel-Stepped Mast


Sliding Mast Sleeve

When I got my Daysailer, it came with a keel stepped mast, using a mast jack. It also came with a curious "sliding sleeve", hinged to a metal plate bolted to the deck over the partners and with a hole for the mast profile. The sleeve was clearly home made, using a grooved wooden block and a piece of bent sheet-metal (aluminum), roughly forming a channel that fits the mast profile (see photo and the detail drawing below).

Mast Sleeve and Disk.

The sleeve should not fit
too tight, and could be waxed

The disk is a good platform to
mount additional hardware

  Sleeve made from
wooden block
with bolted on
sheet metal


The hinge is
drawn upside
down (oops)






  Aluminum Disk 1/8",
held by 6 bolts through deck,
with plywood backing plate.
Use T bracket as
 additional reinforcement
 from underneath




To raise the mast, one would slide the mast foot into the sleeve, then stand in the cockpit, grab the mast about 8' from the sleeve and push it up and then finally forward. The point of the hinged sleeve is solely to give a pivot. When the mast is all the way vertical, the foot lines up with the opening in the deck: from then it slides down through the deck, and needs to be guided onto the pin (1" threaded stock) of the mast jack. With a bit of practice, it's straightforward to do that single-handed, but it helps if you are really strong and tall. Having a second person on the cuddy top to assist makes the job simpler.


Pushing the mast overhead is hard and controlling it from the cockpit can be challenging at times, so I started looking around for alternatives. What I came up with is described below and is shown in operation here (see also the detail drawing below).

Total height is about
2" above the ring on
the mast, before the
mast is dropped.


A 1:8 block and
tackle is fastened
with a shackle
to the eye for
the jib

A single block is suspended
 from a piece of wood held
 by hinges between
the three legs.

The hinge remains
in place with
the mast

The mast
slides in the
sleeve once the
holding pin is pulled.



sleeve detail
showing holes for pin



← Pull here

     ← Bolt with wing nut


Procedure for using Tripod

  1. Insert mast foot in hinged sleeve
  2. Secure with pin (as shown) and attach line at ring
  3. Raise to vertical with block and tackle
  4. Remove pin
  5. Let mast drop down to mast step (mast jack) by letting out block and tackle
  6. Unstepping proceeds in reverse

The process can be seen here.

When raising the mast this way, it's necessary to manually prevent the mast from swaying horizontally, but no lifting is required. Once vertical, the mast can no longer move sideways. When lowering it through the deck to the mast step, gentle forward pressure is needed to keep the mast (nearly) vertical.

The pin is not needed when unstepping the mast: once tipped, the mast cannot slide out of the sleeve until it's almost horizontal. It could slide forward once the mast is nearly horizontal, but letting the mast drop onto its cradle with a smooth motion is enough to prevent that.



Legs: The front leg is a bit longer, and is held by a cotter pin. The two other legs are about 8' long. I used milled maple from the lumber store, so the dimensions are approx 1" x 2" for the cross section. Because the front leg had to be longer than the longest piece I could find, it's doubled near the top and I doubled the bottom end as well. Some kind of quick release pins to attach the side legs to the chainplates would be useful - I'm still using bolts with wingnuts and they take a bit of time.

Pin: Two small holes in the sleeve and matching holes in the mast allow the use of a pin which prevent the mast from sliding in the hinge until it's vertical. If you tried to raise the mast without the pin, the slow pull is at such an angle that the mast would slip horizontally rather than being raised. The pin is not needed for lowering, as long you tilt the mast quickly enough when it comes down; it rarely slides more than a foot if you lower it briskly.

Purchase: I use a 1:8 block and tackle that I got cheaply at some hardware store, but I replaced the rope with an old  halyard for smoother operation. A main halyard is about long enough. I attach the working end to the ring on the mast.

Mast hinge: The sleeve of the mast hinge remains in place after the mast is stepped.

Helpers: It's possible to raise the mast single-handedly, especially if you have a cleat on the cuddy top to belay the rope, for example while you pull out the pin. However, its even easier with a helper as shown in the photos (BTW, that's not me in the photos, I'm pulling on the line that goes off to the side in the middle picture, bottom)

One person is in the boat, who can steady the mast against sideways motion and, when it's already vertical, makes sure that it doesn't tip back when you try to drop it in the hole. The guiding takes a lot less force than raising the mast directly. Using a 1:8 purchase makes that easy, too. Once the mast is dropped to where it's low enough for the mast foot to be close to the mast step on the bottom, you can let go of the mast above and grab the foot to guide it onto the mast jack - the mast won't fall at that time, being held in the partners.

Experience: I've used this contraption now about a twenty times. It's definitely easier on my back, but it requires a little extra time. A small jam cleat on one of the legs to keep the block and tackle under tension when not in use is a planned improvement. The three legs make it very sturdy, and it doesn't require level ground, for the trailer (although I'd avoid a strong sideways slope.)

After the season has started and I've built up the requisite muscles again, I usually don't bother with the tripod, but it's nice to have if the ground slopes the wrong way, or I'm simply tired.


The hinge looks like a standard door hinge you would find at Lowe's/Home Depot. Would you concur? I've also seen the "T" brackets there.
Yes, these are standard hardware store items. I make sure that I keep them well painted and that has kept corrosion in check. (Hammerite spray paint works fine).
From what I can tell the aluminum disk is above deck and that means the plywood backing is below deck (hence the word "backing"). Is that correct?
Correct.The backing is mainly needed to spread the load from the fender washers of the bolts further across the fiberglass. 1/2" would be fine for that purpose, but two layers of 1/4" might work even better as they would be more able to conform to the curve of the deck. Even though the wood is usually protected and normally dry right under the cuddy deck, it doesn't hurt to either oil it really well, or seal it in epoxy. Mine was put up by the PO and it's suffered a bit over the years.
If the aluminum plate is above deck, I'm guessing the hole in the plate is cut in the same shape as the hole in the deck (but cut bigger to allow for the raised lip (partners?) around the mast opening). This way the plate would be flat on the deck.
The hole in mine is precisely the same as for the mast partners. I picture the PO filing it to shape after mounting it to get precise alignment. Because the cuddy has a "lip" around the deck opening. the disk sits a bit above the deck. I bent a simple strip of aluminum around the front edge to prevent any sheets from getting trapped between disk and deck. (The strip is a bit taller than the gap, and the ends taper to the disk, at that point, I bent some of the strip over so I could bolt it in place into the disk from below (or you could use rivets).
When you are in the cockpit and grab the mast 8" up from the sleeve and start to push up, how much force do you think you are having to apply? 80lbs? 100lbs?
I don't grab it 8" above the sleeve, it's more like a third or a quarter of its length.
This gets easier with practice. If possible I like somebody to help me who stands on the cuddy and pulls up on the mast. It's also nice to have a helper to give the mast a little bit of a starting angle, but not required. If you do have a helper, perhaps make a "push stick" so that they can help you push the mast to a good initial angle while standing behind the transom. I usually stand no more than about 2' behind the thwarts when starting to push the mast up. One thing that can make a difference: if you have diamond stays, take them off. They are not really needed (lots of posts about this on the forum) and with lever arm, that could cut 5# of force or more from the original push.
The way I do things is that I first raise the mast to shoulder level. Then, I very carefully line up straight (although I stand to SB of the CB trunk - you have to pick some side). Then I push the mast up by extending my arms and then walk it forward into position. I usually step onto the thwarts to get some extra height.
When you lower the mast, is it the same procedure in reverse? Or do you start out on top of the cuddy, pull the mast up through deck and then jump back down in the cockpit to hinge it down?
If I have a helper, that person's job is to raise mast and hold it, while standing on the cuddy facing aft. Otherwise I just grab the mast at two locations and push it up while standing below. Placing my grip in the right place makes sure I don't lift the mast higher than the sleeve.
The trick is to keep the mast vertical until you are ready to tip it. The sleeve will not hold the mast vertical by itself, all it's intended to do is to prevent the bottom from slipping sideways, as well as holding it in place while hinging.
On the drawing of the hinge setup, what are the two holes in the bottom of the sleeve for?
They were used for a pin to lock the mast foot.
There usually is no need to lock the mast foot in the sleeve. At any angle between 10° and ~90° the mast foot will be held in place in the opening. At 90° it will go in, but if your mast partners are as tight as mine, it will only go in if you are within what feels like 1-2 degrees of the correct angle, if you are off, it just stops - nice safety feature and helps aim the mast. When you lower it, if you aren't "smooth" about it, but very slow, the mast can slip forward a foot once you have it near horizontal (it will no longer touch the hole and slide past it). That won't do any damage, so there's again no need to lock the mast foot. In raising, I've never seen it slip, probably because I quickly lift it to my shoulder level first.


   ~ green ~ lake ~ ~

 Draft 6 2013