St. Martin: Flopper Stopper Pole Installation, May/June, 2010 

Click on the above thumbnail for a map during this time period

At-Anchor Stabilization

By the time we had reached Puerto Rico in early 2007 in our voyage south, it was apparent that some type of at-anchor stabilization was highly desirable in the Caribbean.  We purchased two flopper-stoppers (FS) from Prime Fabrication, but temporized on getting the associated poles.  We hoped that hanging one from the boom would usually be enough, and hoped that when it wasn't, that hanging the other from the power davit would suffice.  The power davit never really worked for us.  It did give minimal additional roll dampening, but it reached out even less far than the boom, and there were no means for keeping the davit from rotating at its base save awkward, ugly, and ineffective use of ropes.  We soon abandoned using the davit, and contented ourselves with using the boom.  We knew that the boom is too short to be maximally effective with FSs, and we knew that one FS was not as good as two.  But we balked at the presumed expense of shipping two poles from the USA to the Caribbean.  And then, while in Trinidad during the hurricane season of 2008, we had to replace our Trojan L16HC batteries, and discovered that freight from the USA to Trinidad via Tropical Shipping was really quite reasonable.  But we continued to temporize on the FS poles.  Finally, after some particularly rolly nights on the way north in the Spring of 2010, we decided to purchase the poles from Prime Fabrication and have them shipped to St. Martin.

We were not quite sure where to mount the poles to the boat.  We knew that several Krogen 58s had mounted on the side of the upper deck.  That was appealing, because it would mean that the poles could be left attached and swung back and locked along the side of the upper deck when not engaged.  We sought the advice of Krogen, and were told that on the 48 North Seas (our vessel) there should probably be mounting plates behind the attachment point.  We had hoped to do all of the work ourselves, and we didn't see how we could install the plates, and we expected that the costs for professional installation would be prohibitive.  We contacted Paul and Julia on Coral Bay, who we knew had poles installed on their rub rails.  Paul gave very useful descriptions and advice, and I was able to create a detailed specification for Prime Fabrication concerning L-shaped mounting plates for the rub rails.  One side of the L fits down on the rub rail and the other fits up against the outside of the hull.  The positioning of the knuckle on the plate was critical:  when in upright stowed position it should not position the pole outside of the rub rail (lest it get scraped by a dock or piling) but it should be out as far as possible in order to clear the protruding cap rail above the rub rail without getting too far away from the upper deck and/or upper rail, where it would be secured by a chock manufactured and supplied by Prime Fabrication).  Here is a pdf of the mounting plate that Prime Fabrication manufactured to my specifications.

While we waited for the poles, plates, knuckles and chocks to arrive, we had plenty to do.  And plenty of help too, since Hunter (Arctic Tern) was also in St. Martin, working on projects of his own, providing massive amounts of assistance to me, and also waiting for us so we could cruise to Bonaire together.  The first order of business was to tighten the shrouds that provide lateral support for the mast.  They were quite loose.  Hunter had a device for measuring the tension, and the shrouds were initially so loose as to be off the scale.  We tightened them to 1300 lbs., and later backed that off to 1000 lbs. on the advice of Krogen.  Next, we installed folding steps on the mast in such a position as to facilitate access to the top of the mast.  Then, using the new steps, I could survey the top of the mast and consider how best to attach the blocks that would be used to raise and lower the FS poles.  I designed an aluminum plate, had it manufactured at FKG rigging, attached it to the top of the mast, and attached the new blocks to the plate.  When the hardware arrived from Prime Fabrication, Rene (Gypsy Blues) -- then working at Island Water World -- was kind enough to let us use IWW as receivers, so that we didn't have to try to solve the problem of getting a 13' heavy package transported from Philipsburg to Simpson Bay Lagoon.  We installed the mounting plates on the rub rails and waited a day for things to dry a bit.  Installed a pole and raised it to the upright stowing position, to see how far away it was from the upper deck and the upper rail.  Too far to reach the chock if it was mounted directly to the side of the deck.  Hmmm.  How to mount the chock to the 1 1/4" rail?  None of the chandleries have clamps for rails larger than 1".  Hmmm.  We have fishing rod holders attached to the lower rails, which are also 1 1/4" rails.  Wonder how far the rod holder would stick out if it were reversed and configured perpendicular to the rail?   Holy cow, they almost reach out to the position of the upright pole and they can be removed if that ever was desirable.  Off we go to FKG, and commission SS plates to be welded onto the end of the rod holders, said plates to receive the chocks.  While waiting for those, I cut some spacers of starboard, since the modified holder with chock attached would still be just a bit too short.

As this is written we have employed the new FS/pole installation just once on a very rolly night at Portsmouth, Dominica.  The degree of roll dampening is gratifying and impressive.  But the poles vibrate when the FSs "bite in" as they open, and the hollow poles combined with the knuckle/bracket is quite noisy.  Also, with the supplied lines used for raising/lowering the poles, the poles will be very hard to raise when the FSs are still in the water.  The lines are too small, and dig into my hands, and the pull on the lines in rough water is daunting.

Adjustments will have to be made, but the basic installation is sound, we believe.  (See below for subsequent modifications.)

Measuring the tension in the mast shrouds

Hunter tightening a shroud

Installing folding steps on the mast

Aluminum plate that we added to attach at the top of mast the blocks for raising/lowering the poles

Bringing the poles to the boat

Installing the mounting bracket

Installing pole and its various lines

Upper side view of mounting bracket and knuckle

Looking down on the bracket and knuckle

Chock attched to upper rail for securing pole in raised (un-engaged) position

Another view of a chock, a pole, and a flopper stopper

Employing the new flopper-stopper arms at Portsmouth, Dominica

Submerged flopper in closed (falling) position

Submerged flopper in open (rising) position -- resisting the rise

A closer look at a flopper at open position -- note ruler for scale

Revisions and Additions to the flopper-stopper system (written 9/29/2010)

First, a bit of history.   When we bought the boat in 2005 (second owner), the line that raises the boom was inside the mast.   It came out near the bottom of the mast, and below that point there was a cleat.   In 2007 when the winch in the davit began sounding "sick", we replaced the power winch and also installed a hand winch at the bottom of the mast.  The idea was to have a backup in case the power winch ever failed.  This modification required that the line be moved from inside the mast to the outside.   We soon realized that using the hand winch to raise the dinghy into position on its deck stand required moving back and forth a number of times between raising the end of the boom and shortening/lenghthening the line hanging from the boom.  The dinghy weighed too much to remove a line from a cleat and attach it to the hand winch we had installed.  The solution was to add rope clutches that would secure the two weight-bearing lines so that one or the other could be attached to the hand winch.   The resulting system works well; for security we use the hand winch to lift the dinghy up out of the water up to the rub rail each night.

Those unable to learn history's lessons are doomed to repeat its mistakes.   When I installed the flopper stopper poles, I initially only had installed cleats to secure at the base of the mast the lines that raise/lower the poles.  I hoped to be able to transfer such a line from the cleat to the winch by just grasping the line.   But the 1/4" spectra lines were too thin and slippery to grasp and it turned out to be almost impossible, and dangerous at that.   With the FS down, the line was periodically tightened so much that it was not safe to have fingers between it and the mast.   I replaced the spectra lines with 10mm woven line, and although this proved to be much easier to handle, it was still dangerous and difficult.  The solution, of course, was to install a set of rope clutches for the FS poles.

The resulting system, while not as elegant as it would have been if all clutch needs had been anticipated at the time of the installation of the hand winch (for then the top two separate clutches on the starboard side could have been a "double"), is very functional.   The lines that raise/lower the poles first go through the clutch, and then are -- as backup -- attached to the cleat immediately below.  When it is time to raise a pole, the line is removed from the cleat and wrapped around the hand winch.   The rope clutch is then released and the pole is easily raised by using the winch.  The pole is raised until it is not quite vertical, but just far enough away so that the FS does not break the surface and does not hit the hull.   Barb and I carefully lift the FS over the cap rail and set it temporarily on the side deck and then the pole is raised the rest of the way and secured in the chock.   The FS is lowered by essentially reversing the process, using the winch to ease the lowering of the pole to the correct height and then locking that position with the rope clutch.

Note that there is not a block at the end of the pole; the line from pole to FS is a fixed 12 feet.  There is no additional line from the FS to the vessel; the pole is raised until the line can be easily fetched with a short boat hook and then can be brought to the edge of the hull so that the FS can be lifted out of the water by hand.  Your mileage may vary.  We know of other installations in which a block is employed at the end of the pole so that the FS can be raised/lowered up/down from the end of the pole.   And we know that some folks attach a separate line that runs from the FS to the vessel so that the FS can be pulled in to the side for lifting aboard.  So far we have seen no need for either complication.

Upper clutches: for flopper-stopper lines; bottom clutch: for line that lifts the boom end

Davit for lifting dinghy to deck

Overview of all hardware installed at base of mast

Hardware installed to serve as backup to the davit

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