SEA SPRITE WEEKENDER 23 TABERNACLE AND MAST RAISING SYSTEM – by Dejan Radeka

IMPORTANT…CLICK ON IMAGES TO ENLARGE TO FULL SCREEN

I love my Sprite but one of the things I don’t like about the Weekender design is the foreshortened trunk cabin with the deck stepped mast.  As designed, there is no easy way to hinge the mast at the deck for easier raising and lowering because the cabin trunk is in the way.  This forces one to use a crane or fixed gin pole at a boatyard or yacht club.

My philosophy behind choosing the Sprite was to find the prettiest and most seaworthy all around classic keelboat that I could trailer, launch and store on my own, without a boatyard.  There are plenty of deep water ramps where I live, and the 23 footer, at about 5000 lbs including a trailer, is not beyond the capacity of an average SUV or mid size pickup.  It also fits in my driveway.  After getting a trailer made for the boat all I needed to do to be completely self-sufficient was solve the mast raising problem.

Assuming that the mast can be hinged somehow, the approach then is to rig a hinging gin pole at deck level, and in line with the mast step.   The hinging gin pole acts as a lever, with a fulcrum at the mast base.  This is rigged using the jib halyard fixed to the end of the gin pole, a block at the stem-head, and a line lead aft to a winch, to raise and lower the mast.  My father used such a system to raise and lower the mast on his S&S designed 22 foot Kestrel sloop.  His arrangement had a single pole butted at the base of the mast, and required guys to keep it vertical.  I decided to fabricate an “A frame” gin pole instead, so as to do away with the need for the guys.  But first, back to solving the problem of hinging the mast.

The mast needs to hinge at a height that will clear the cabin trunk.  Collaborating with my father, we devised a tabernacle / mast step for my Sprite, with a pivot point higher than the cabin trunk. Our design is loosely based on tabernacles seen on some classic gaff rigged boats, as well as a more modern interpretation that we saw on a Cape Dory 27 Pilothouse cutter, that had a similar cabin trunk clearance problem as the Sprite.  (See Figure 1, “Tabernacle side view”)

Figure 1:  Tabernacle Side View

 

 

 

 

 

The tabernacle needs to be strong enough to handle the loads associated with raising and lowering the mast, and once the mast is up, it needs to fix the base of the mast firmly.  We designed it based on the specifications of the Dwyer DM-450 mast section that came standard with my 1974 hull.  One can vary the design dimensions if using a different mast section.  (See complete “Tabernacle Specifications, Materials and Instructions” at the end of this article for complete fabrication and installation instructions for the Tabernacle.)

An important note:  My assumption in writing this article is that your boat either has no deck/core issues, or you have already repaired a sodden deck.  You should not proceed if there are deck/core issues.  Repair the deck first, or as part of the project.

The design also requires minor modifications to the mast.  The bottom of the mast will need to be cut for two reasons; first to maintain the original total height of the rig, and second, a clearance relief cut is made to allow the bottom of the mast to arc into the step.  You also need to drill a pivot hole in the mast.  (See “Mast Modifications” at the end of this article for complete instructions)

The next thing to fabricate is the A frame gin pole.  The gin pole needs to fit within the foretriangle; so it will be about 7-7.5 feet tall.  The A frame design is made with two poles, a cross piece, and requires two hinging bases.  I have been a windsurfer for over 30 years so I had alot of accumulated windsurf hardware and broken masts collecting dust in my garage.  I used two carbon fiber mast sections for the uprights.  I used a piece of 2×5 scrap oak, through-bolted through the tops of the masts, for the upper cross piece.  I used two mast base universals for the hinging bases of the gin pole, bolted to pieces of scrap 2×6.  (See Figure 2:  “A-Frame Gin Pole” and Figure 3: Gin Pole “Foot”)

 

 

Figure 2:  A-Frame Gin Pole

 

 

 

 

 

Figure 3:  Gin Pole “Foot”

 

 

 

 

 

I realize that most people reading this article will not have the accumulated windsurf gear that I had.  In lieu of that the key parts for fabrication are two poles, and a hinge assembly for each foot.  I recommend a visit to the marine consignment shops.  Two old spinnaker poles would work well for the uprights.  I recommend a minimum OD of 2” for it to be strong enough.  For the hinging bases, cast aluminum spinnaker pole deck chocks will work well.  I would cut off or remove the spinnaker pole ends.  Drill out the chocks and one end of the pole for a 5/16” through bolt.  This will be your hinge assembly.  Bolt the chock to a piece of scrap 2×6.  In lieu of spinnaker chocks, you can also source aluminum (or other) angle iron at most small hardware stores.  Two pieces of 2×2 angle bolted to a scrap of wood, and cross drilled for a through bolt can also make a good hinge point for the uprights.  Lastly, the cross piece can be any scrap wood you have, as long as it is not a soft wood, like pine.

I also recommend making a support for the stern, to facilitate the process of setting up the mast for raising/lowering.  If you have a stern pulpit, this can be as simple as a piece of 2×6 that is notched to receive the mast.  This piece should be about 4-5 feet long.  You will lash this to the pulpit in the center.  If the boat doesn’t have a stern pulpit, then you can fabricate an A frame support to hold the mast.  (See Figure 4:  Stern Support)

Figure 4:  Stern Support

 

 

 

 

 

Now for the moment of truth.  You’ve fabricated and installed the tabernacle, made the necessary mast modifications, and built the gin pole.  It’s time to rig the gin pole and raise the mast.

Hints and Tips:

• Try to find a level spot to park the boat, preferably as far as possible from the typical beehive of ramp activity.
• STAY AWAY FROM POWER LINES!!!!
• Position the boat with the stern into the wind.  This may be difficult in some places but try to avoid a cross wind.
• As a safety precaution, be sure to have a clear area behind the boat, where there is no activity, people, parked cars etc
• You only need two people.  More people will not help you and only causes distraction.

 

 

Rigging the Gin Pole (See Figure 5: Rigged Gin Pole)

• You can execute this entire process with two people.
• Setup the aforementioned stern support first.
• Lift the upper end of the mast (ie the end that is resting on the stern pulpit) up onto the support.  That person should stay there.
• Lift the lower end of the mast (ie the end that is resting on the bow pulpit).  Slide the mast towards the stern.  The mast will slide on the stern support.  The stern person needs to make sure the mast stays on the support, and will also clear any shrouds, halyards etc that might snag.
• Slide the mast back until the mast pivot hole lines up with the tabernacle pivot hole.  Push the mast down into the tabernacle and slide the pivot bolt home and snug up the nut.  The mast is now sitting with it slower end in the tabernacle, and the upper end resting on the stern support.
• Stand the gin pole up on the deck, in line with the tabernacle.
• Lash the foot pieces fore and aft so they don’t slide.
• Attach the jib halyard to the cross piece.  Make sure the halyard tail is tied of securely as well.  I use a piece of scrap dock line on the cross piece; I tie a bowline through a hole in the cross piece, and then tie off to that.  Do NOT use/clip the halyard shackle here; for safety, tie a bowline.
• Attach the lifting line to the cross piece, again use a bowline.
• Run the lifting line through a turning block shackled to the stemhead, and then back to a primary winch.
• Snug everything up so that the gin pole stands a bit aft of vertical.

Figure 5:  Rigged Gin Pole

 

 

 

 

 

Raising the Mast  (See Figure 6:  Raising/lowering the mast):

• Again, you only need two people.  More people will not help you and only causes distraction.
• Shrouds that should be attached include the back stay, the aft lowers (on Weekender) and the uppers.  The forward lowers, and the fore stay, are loose.
• Put 4 wraps on the primary winch.  The person winching also needs to tail.  The 2^nd person will be a spotter, to make sure there are no issues while the mast goes up.  They will also guide the mast if there is any cross wind.
• Take up tension on the winch line; crank the mast up a foot or so off the stern support and double check everything:  Gin pole position, all knots, the “run” of the lifting line, etc.
• Start cranking it up.  Be smooth with the winch.  The spotter needs to check the aft lowers; for example on my boat, for some reason they always catch on the forward cockpit coaming lip at the cabin side.
• The spotter also needs to check all the turnbuckles, make sure they are not canted sideways and catching on anything(especially if you don’t have toggles).
• Crank the mast all the way up.  The last 15-20 degrees from vertical become really easy and it will just pop right up.
• Once vertical, crank some tension onto the lifting line, so that you have enough slack to attach the forestay.  Tie off the lifting line and get the forestay attached.
• Once the forestay is attached, you are safe!
• Now you can unrig the gin pole, and proceed with the rest of your rigging and launching process!

 

Lowering the mast:

• Lowering the mast is essentially the reverse of the raising process.
• STAY AWAY FROM POWER LINES!!!!
• Again, you only need two people.  More people will not help you and only causes distraction.
• Rig the gin pole as before with jib halyard and lifting line but in the “down” position with the cross piece about a foot off the deck.
• Loosen all of the shrouds.
• Setup the stern support
• Crank on the lifting line so that you can detach the forestay.
• Detach the forward lowers.
• Detach the forestay
• Station one person at the primary winch and one person at the mast as spotter
• The winch person should put 3 wraps on the winch
• The spotter, standing on deck, pushes on the mast to start it down, and the winch person will begin to feel the tension as the rig goes past vertical.
• Winch person can now slowly feed the lifting line to lower the mast.  This requires someone that understands how to feed a line using a winch.  You do not want to get an over-ride while doing this so be careful and take your time.  One hand goes flat on the 3 wraps and the other hand feeds out the line.
• The spotter needs to check that nothing snags, and should guide the mast if there is any wind.
• At the end the spotter should guide the mast into the stern support.
• Once down, unrig the gin pole.
• Then unbolt the pivot bolt and remove it from the tabernacle while firmly holding the butt end of the mast.  The mast will want to push up at you like a see saw.  Carefully guide the mast out of the tabernacle, then slide it forward to place it onto the bow pulpit, while the stern person insures that the mast stays on the stern support.
• Finally, lower the upper end of the mast from the stern support down onto the stern pulpit.

Figure 6:  Raising/Lowering the mast

 

 

 

 

 

Notes in Figure 6:

• Boat trailer parked in nice level area away from people and cars.
• Trailer hitched to vehicle and chocked
• Boat is strapped to trailer, all poppets checked and snugged
• Area aft of the boat is clear of any obstructions and people
• The spotter (in green shirt) guiding the mast to the stern support.
• In this photo I am the winch person (behind spotter) and I am using the cabin top mounted halyard winch because its more convenient; you can also use a cockpit sheet winch.
• Neither person is under the mast at any time!

 

Tabernacle Specifications, Materials, Instructions:

 

 

 

 

 

 

 

 

 

 

 

 

 

Mast Modifications: