Repairing The Lower Boom Vang Mount

Failed lower Boom Vang Mount and mounting bolts

Last fall we were sailing along nicely on a medium wind day when we heard a loud bang, the bang got our attention but looking around we were not able to see anything wrong, shrouds and stays were fine and the rest of the rig also looked OK.

A few minutes later as we were still trying to figure out the first bang a second loud bang happened and the boom jumped up and we could see the Boom Vang hanging loose, mystery solved!

With no Boom Vang the trip back home was cautious, I probably could have rigged a temporary lower mount but the wind was not too bad and we were not far from home so we did not rig a temporary mount.

Materials for the lower Boom Vang Mount repairs

Supplies for the repair, 3/8 inch drill motor, T Handle Tap Wrench, small hammer, small pin punch, HeliCoil Thread Repair Kit (HeliCoil is the trademark and one of the early if not the first with a thread repair kit, others now sell similar repair kits, I have chosen to stick with the original) (the kits come with a drill bit, special tap, coil inserts and an insertion tool), Thread cutting lubricant and Silicone Paste to help cut down on corrosion between the threaded insert, mast and fastener, see also the “Secret Sauce“, Teff-Gel is very popular for preventing corrosion as are several other items, remember do not assemble the fasteners without some sort of protection or corrosion can occur and things can fail prematurely.

Tapping the holes for the HeliCoil Inserts to repair the lower Boom Vang Mount

Drill out the old holes with the proper size drill bit that comes with the tread repair kit.

Tapping the new threads after the hole was drilled  the HeliCoil kit.  Note: The tap that comes with the HeliCoil Repair Kit is a special tap, the number of threads per inch need to match to a smaller size fastener so make sure you do not misplace the tap that comes with the kit, I doubt you will be able to find a replacement at your local hardware store.

Also remember to use thread cutting lubricant appropriate to the material you are tapping into, in my case the A-9 Cutting Fluid was designed for cutting Aluminum since I have an Aluminum mast..

HeliCoil for the Boom Vang Repair showing the tab/tang used to help insert the HeliCoil into the threaded hole. The tab/tang needs to be broken off with a small pin punch once the HeliCoil has been inserted in the repaired hole

A closeup of the HeliCoil insert on the insertion tool showing the tang or tab that is used to thread the insert into the tapped hole.

The tang or tab is broken off after the threaded insert is in the proper location.

Be careful you have the insert in the correct location before the tab is broken off, and remember to protect the threads from corrosion with a good anti-corrosion paste or gel.

Finished repair with the lower mount of the Boom Vang fastened in place

The finished repair back like it was before the bang.

But after thinking about the repair for a short time I did not like it, I figured the same stresses that caused the first failure might come back in the future.

See the next step below for what I think is a better and safer final solution.

Revised Boom Vang repair showing the lines going around the mast

This shows the final repair, sorry for the bit confusing picture.

I decided to use some AmSteel line from Samson Rope (12 strand single braid non-rotational line out of Dyneema, similar in strength to St. Steel but lighter and no rough edges) and put a round turn around the mast so the lower fitting was mostly loaded in shear with very little tension on the fasteners.  With the AmSteel going around the mast the bottom fitting is used to keep the AmSteel from slipping up and getting out of position.  I did this for both the lower Boom Vang line and the Cunningham lower mount.  There was just enough space in the lower mount for the six strands of AmSteel to be threaded though the lower fitting.

I spliced the AmSteel using a Brummel Splice, I spliced one end and then threaded the line through the fittings and used a McDonald Brummel Splice as explained by Brian Toss in several of his books, the McDonald Brummel only requires access to one end of a line to make the splice where a standard Brummel Splice requires access to both ends of the line.

Thanks for you interest in and support of Boating Safety

 – c / m –

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Avoiding The US Coast Guard Vessel Documentation Scam

US Coast Guard Vessel Documentation

There seems to be a bit of a scam going around with several companies offering to “help” you renew your USCG Vessel Documentation, the catch?  The help will cost you several times the normal cost $ 26.00  the US Coast Guard charges.  Some people in a sailing group I belong to have fallen for this scam.

The Vessel Documentation scam works in at least two ways,

1) You go  to the internet and search for something like “USCG Vessel Documentation” and click on one of the links that looks like a Vessel Documentation link, the bogus links look real official as do the web pages.  From there you are prompted to click on some links and enter your vessel information and pay some money.  The catch?  One of the sites I looked at wanted $ 76.00 for a single year, a nice $ 50.00 service fee.  The Coast Guard site is so so for search engines so the official US Coast Guard Vessel Documentation site was down toward the bottom of the first page for me, so you need to look and be careful or use the link posted below.

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NOAA helps ports recover from Hurricane Harvey

I like it when NOAA & the USCG show that the Govt. can be responsive in times of distress and they were ready to go before landfall.


Hurricane Harvey is the first major hurricane of the 2017 Atlantic hurricane season. Harvey strengthened to a Category 4 reaching landfall along the Texas coast on Friday, August 25, at peak intensity. By the next day, the storm weakened to a tropical storm bringing torrential rainfall to the region.

Before Harvey reached landfall, Coast Survey headquarters and field units were planning and positioning assets in strategic locations in proximity to the Texas coastline. Two navigation response teams—small vessels with three-person crews—were deployed and awaiting tasking for survey work prioritized by the U.S. Coast Guard, in coordination with the U.S. Army Corps of Engineers, ports, terminal operators, state officials, and local emergency responders. The western Gulf Coast navigation manager, Alan Bunn, was positioned at the Houston/Galveston Incident Command Center (ICC), to coordinate response efforts. The eastern Gulf Coast navigation manager, Tim Osborn, traveled from Lafayette, LA, and was positioned at…

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It wasn’t just Jefferson. Congress initiated Coast Survey legislation, approved #OTD 210 years ago

A bit on the birth of NOAA way before it was NOAA, seemed simpler back then, just survey a bit of coast. That was followed by surveying and setting points from coast to coast.


On this date in 1807, President Thomas Jefferson approved an act to provide for surveying the coasts of the United States. NOAA has long honored Jefferson — but what of the legislators who saw the need, wrote the bill, and sent it to the president?

On December 15, 1806, Samuel W. Dana (CT) introduced a resolution instructing the House of Representatives’ Committee of Commerce and Manufactures to “inquire into the expediency of making provision for a survey of the coasts of the United States, designating the several islands, with the shoals and roads, or places of anchorage, within twenty leagues of any part of the shores of the United States.” Dana was joined in debate by Jacob Crowninshield (MA-2), the chair of the Committee of Commerce and Manufactures.

Samuel Dana (left) represented Connecticut in Congress from 1797 to 1821. Jacob Crowninshield, of the famed American maritime family, chaired the House Committee on Commerce and Manufactures in the 9th Congress. Samuel Dana (left) represented Connecticut in Congress from 1797 to 1821. Jacob Crowninshield, of the famed American maritime family, chaired the House Committee on Commerce and…

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Book Review: A History of Sailing in 100 Objects

A History of Sailing in 100 Objects

A History of Sailing in 100 Objects

Have you ever wondered about the history of sailing equipment that we use every time we go sailing?

Well fear not, “A History of Sailing in 100 Objects” by Barry Pickthall will fill in some of the gaps, starting with the earliest known picture of a sail from about 3,500 BC on the Naqada II Pot to the GoPro camera in 2006.

Yes a bit eclectic in many ways but a nice read.  The book has the object explained with text on the left side and a picture of the object on the right side.  This bite size method makes the book easy to read and digest in short bits.

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Building an Aids to Navigation Demonstration Display


Aids to Navigation demonstration chart of Elliot Bay and Seattle, the Aids to Navigation are demonstrated using flashing LED’s. The lights flash with the same characteristic as the lights on the water.

This is an Aids To Navigation (ATON) display demonstration board I made, there are flashing LED’s to demonstrate selected ATON’s in the Elliot Bay area around Seattle Washington.

There are 27 Aids represented from just south of the Alki Lighthouse to the Shilshole Marina.  The chart is about 24 inches square.

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A monumental history

Interesting history of sea floor charting


On September 15, 2016, President Obama designated the first marine national monument in the Atlantic Ocean. The Northeast Canyons and Seamounts Marine National Monument includes two areas: one that includes four undersea mountains, called “seamounts” – Bear, Mytilus, Physalia, and Retriever; and an area that includes three undersea canyons – Oceanographer, Lydonia, and Gilbert – that cut deep into the continental shelf. These sea features have monumental histories.

Monuments map, by Leland Snyder, Office of Coast Survey Coast Survey cartographer Leland Snyder used several data sources to create this map of the Northeast Canyons and Seamounts Marine National Monument.

Bear, Mytilus, and Physalia Seamounts were discovered by oceanographers with Woods Hole Oceanographic Institution, and they were named for small Woods Hole vessels that began making forays into the deep sea in the 1950s. The Bureau of Geographical names does not know the origin of the name “Retriever Seamount,” but NOAA historian Skip Theberge thinks it was probably discovered and named…

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NOAA’s Secret Weather Sites


HADS Home page showing over 16,000 NOAA weather sites

Most sailors in the Seattle area are familiar with the West Point and Seattle NOAA weather sites on the internet. But did you know that those sites are only the tip of the iceberg so to speak of the over 16,000 NOAA weather observation sites. There is one at the Alki Lighthouse in West Seattle for example.

Finding the station closest to your location from the over 16,000 weather observation stations in the United States and Canada can be a bit of a challenge even if you have the secret handshake on where to start.  But lets give it a whirl.

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