Monitor Windvane

Just yesterday a friend asked me to help him with his Monitor Windvane and sort out some things as the previous owner could not get it to work properly.  First and foremost, don't make it too complicated; simple means less to go wrong.
The previous owner had made some very small mistakes in the installation of an under deck autopilot using a boat shift cable to operate the vane's rudder, but making a very clean and out of the weather installation.  This is not the first time I've encountered this ingenious method to steer the boat but you must not let the electronic autopilot interfere with the operation of the wind vane.  During the installation a very small detail was overlooked. The two machine screws he used to mount the shift cable interfered with the rotation of the vane's wind blade, not allowing for proper travel and actually jamming the vane in place.  Small mistake, but big bad results. That little mistake made the entire vane inoperable.  Once we removed the screws, voila, a working wind vane.
The most common question I am asked about the Monitor Windvane is:

 "How can I stop the line that adjusts the wind vane to the apparent wind?"

 One cure is to pull more tension on the control lines via stronger bungee cord or multiple loops of bungee cord.  The instruction manual shows this clearly.  I have found that excessive pull on this line just makes it harder to adjust, therefore I suggest a much easier approach.
The sheave that is on the vertical shaft leading to the chain sprocket is adjustable up and down.  Make sure the adjusting lines are lead fair with no chance of chafing and as straight as possible leading to the cockpit.  The Monitor Windvane is notorious for this adjusting line jumping off the sheave.  Proper lead and tension is critical.  There are two methods of retaining the line around the sheave. One is to mount a small fair lead that will accept both leads just forward of the adjustment sheave making the line come in contact with about 80% of the sheave diameter.  This line guide will have little force on it but must be mounted securely.  The other method is to run a smaller adjustment line around the sheave one complete turn then back to the cockpit and adjust it properly with a bungee cord holding tension on the line.
I have had a lot of experience with different types of vane gear. Some work better than others.  For me its been the servo pendulum that has given the least problems and the best service.   One must marvel at the simplicity of it once you become familiar with its workings.   Rudder control lines must be as friction free as possible because of the continuous  back and forth movement of the lines.  Some people prefer the tail end of these lines to terminate at the end of a short section of stainless steel chain which latches into a chain hook making small adjustments and quick release possible.  The chain and hook assembly is shown in the manual and most manufacturers suggest this method be used under the tiller so as not to drag across the top of the tiller when released.  Alternatively, the method I prefer is to have two opposing cam cleats thru-bolted to the top of the tiller making it much simpler to make fine tuning adjustments and most importantly, a quick way to release these lines. This arrangement also keeps the tiller from lifting and is good at keeping the lines engaged while stumbling about in the cockpit.
I have often heard people naming their tillers with some pretty creative names.  Among them are Attila the Hun and Jesse Helms.  (Feel free to share yours)  It isn't any wonder we feel obligated to give our tillers endearing names; they make great crew who don't eat, sleep or have to take breaks.
One last thought while watching this amazing piece of equipment do its thing; don't forget to keep a good look out.

Rigging: Part 2 - The mast at deck level

There are three basic types of mast locations: Keel Stepped/through deck, Deck Stepped located on deck and Tabernacle

Keel stepped masts travel through the deck and are normally sitting on a mast step located in the bilge. This type of mast must be centered in the deck with the old style wooden wedges driven in between the mast and the hole in the deck.  There are many different types of wedges including composite materials and on most modern boats a two part polymer which sets up semi-rigid and can be removed at a later date.  This junction between the mast and the deck should be checked periodically for corrosion, rust, rot and mildew which can damage the spar making this area the weak link in the rigging. This inspection should also include the mast boot.
Deck stepped masts sit on top of either the cabin top or the deck. This type of rig will have a compression post inside the cabin which should also be checked periodically for corrosion, rust, rot and mildew. The mast step fitting on top of the deck or cabin top should be thru-bolted and well sealed.  Special attention should be paid to stainless steel bolts thru-bolted through an aluminum deck step.  The only safe approach to inspecting these bolts is to remove and replace them and make sure they are of the same grade of stainless steel.  There have been incidences where the mast was swept from this fitting due to corroded stainless steel bolts which sheered under load.  Any and all attachments to this fitting should be checked for damage and inoperable shivs if applicable.
Any and all tangs, bails, bolts and rivets are subjected to very high load of stress in this area and is common to all types of masts.
Boom vang bails, cheek blocks and weldments should also be carefully inspected.  I strongly suggest removal of these items for inspection.   You can't inspect what you can't see.
Reefing hardware located on the mast is often overlooked and yet is just as important as the standing rigging.
Modern tabernacles are made of stainless steel and require the same maintenance and inspection as the previous types.
The pivot pin and locking pin should be inspected for damage and corrosion regularly.

The Rigging: Part 1 - Masts and inspections

Quite often owners and brokers will tell you that the rigging on what could be your next sail boat has been completely redone.  Rarely is this the case.
To be sure you should contact a yacht surveyor or a qualified rigger to do an on-board and up the mast inspection. Once you have the report you will have a better idea of what you are dealing with.  Oftentimes you will discover that the rigging has not been replaced and only the cable ends at deck level were replaced with Sta-Lok or Norseman fittings.  One must consider not just the end fittings on the cable at both ends but the cable itself.  Rigging replacement should include turnbuckles, tangs, toggles and chain plates and let's not forget about the cables and any runners you may have.  Running back stays, jumper stays, bob stays and whisker stays are just as important.  Spreader fittings both at the mast and at the spreader tips should be carefully inspected or replaced.
The mast step should be of sound material giving the mast a firm foundation.  It should be replaced if there is any sign of weakness or damage.  The mast base fitting or locating timbers should be free from rot or splits and should be treated with anti-rot and anti-fungal chemicals.  Steel steps should be cleaned and sealed as often as necessary.  An aluminum mast and the lower end plate should be free from blistered paint or corrosion of any type.  Severe corrosion at the mast base can sometimes be cut off by a few inches to remove the corrosion.  The mast will sit short but the replacement of the rigging cables can compensate for this.  A few inches will not be noticeable nor will it adversely affect the performance of the rig. If the mast has to be shortened more than a few inches or even feet this is not a big deal.  The section to be replaced should be welded or screw fastened or perhaps pop riveted in place.  The method you chose should be approved by your surveyor/rigger and your insurance company.
We will continue up the mast with suggestions on winch pads, cleats, spreaders, tangs, bails and masthead fittings tomorrow.