That Sinking Feeling

I guess the truth of the matter is that all sailboats can sink. Similar to the line in the Titanic movie:

"She's made of iron, sir. I assure you she can, and she will." -Andrew

The lead in a keel boat will gladly help a sailboat head to the bottom of the sea given a chance.

This came up today because I received this message on positive flotation from Bolero's original builder, Cape Cod Shipbuilding. This guidance was in response to a recent sinking of a Shields class boat during this summer's Edgartown Regatta. Unfortunately this isn't an isolated event.
Cape Cod Shipbuilding would like to take this opportunity to share general air tank information with all Shields owners. Please feel free to share this information with owners who have not received it. The flotation system in the Shields consists of 4 air tanks; one in the bow, one in the stern & 2 in the floor. When the Shields buoyancy was initially tested during design development, a Shields was tied to our dock swamped for 8 hours & never sank. The tanks held air & kept the deck above water level. New Shields are built with the same buoyancy to prevent sinking. However, over time damage can occur to the air tanks that can cause a boat to sink if swamped.

Air tanks in Cape Cod built boats can be easily tested & repaired. An air tank test kit can be purchased through us that includes the tools needed to test, drain & install new tank test plugs. Each floor air tank comes with a threaded tank test plug. To test, find the tank test plug in the bilge, remove it with an allen wrench. If there is a slight inrush or outrush of air, the tank may be tight. If no air exchange is noticed, put pressure in the tank (1 to 2 P.S.I.) by the use of an air compressor, or bicycle pump. Build up pressure in the tank and hold it for 5 to 10 minutes. If there is still pressure, the tank may be tight. It is possible that the pressure is closing a crack shut, so multiple tests may be necessary. If pressure is lost, build back pressure and listen for air escaping to locate the leak. Sometimes the leak is too small to detect by ear and a 50-50 solution of water and a liquid dish detergent can be made to help find the leak. Apply this solution with rag or small disposable paint brush around the areas you suspect are leaking. Large bubbles will indicate the location of the leaks.

A few owners have inquired about buoyancy bags; In order to put enough buoyancy bags in the Shields to keep it floating, they must take up the same amount of space as the 4 existing air tanks. Repairing damaged air tanks as opposed to modifying with air bags is the better solution. Once you have determined there is a leak, it must be properly repaired. Once the leak is repaired, re-test as you may find smaller leaks. Plastic inspection ports are not recommend in any of the air tanks to pump out the water. This adds one more hole in the air tank where leaks could occur & plastic inspection ports fail under pressure. The proper solution is to make the air tank tight. The Chris Craft Shields were never built air tight but they can be repaired to be air tight. Many of the tops of the Chris Craft bulkheads were never fiberglassed to the underside of the decks.

Common causes of air tank failure:
  • Teak Handrail & Toerail fastenings over time can elongate the hole in the fiberglass, or replacement teak trim was improperly installed/bedded.
  • The athwartships teak floorboard support that holds the turning button is fastened to the 2 floor air tanks & the fastenings can elongate the hole in the fiberglass over time.
  • Water if left to freeze in the bilge over the winter can put cracks in the floor air tanks.
  • Air tank hatches with 2 hook style hatch latches on each hatch. This system does not prevent water from pouring in during a swamping. It is imperative that Shields with the 2 latches per hatch be upgraded with 4 new wing nut style latches per hatch. All hatches need good gaskets in order to create an air tight seal.
  • Most aft tanks have an adjustable backstay and an ungasketed hole where the backstay lines go through the bulkhead. These holes allow water to enter the aft airtank.
We recommend checking your air tanks each year and always comply with class rules for safety equipment. When installing new hardware keep air tank integrity in mind; use gasketed thru-hulls and properly drill, tap & bed all fastenings. Everyone wants a fast boat but safety should be our number one priority.

The Goodwin's
I believe that this photo (which I have posted many times before) is the test that the Goodwin's are speaking of.



Bolero is no longer representative of the Shields class boat as tested in this photo. During her major redesign and renovation the floor / seat tanks were remove. Therefor, it is my belief that should water get below, into the cabin, she would sink like a stone. In this respect she is very much like any keel boat with a cabin.

But in many ways she is still an old Shields at heart which definitely separates her from a more traditional cruising, weekending or day sailing keel boat.
  • She doesn't have cockpit drains. So in the event of a knockdown or any event that floods the cockpit she will have to be bailed out by hand and quickly to prevent water from getting down below and sinker her.

  • She still maintains the low freeboard that I suspect is one of the main culprits of the various Shields sinkings that have occurred over time.

  • She still carries the large sail plan of a race boat.
I do believe, however, that Bolero is more resistant to sinking than a stock Shields. Although she has lost part of the permanent buoyancy from her original design we have the added benefit of a bridge deck and an enclosed cabin. In addition we have a reef-able sail plan which would never be available to the racing Shields.

Here is our plan to prevent knockdowns and flooding on Bolero.
  • Sunny and Beautiful - Life vests and throwable cushions handy and the companionway hatch is closed without any hatch boards in place. This is how we spend most of our time under sail.

  • Pre-Reefing Conditions - Pretty much the same as above except the backstay, outhaul, cunningham and halyard have all been tightened to flatten the sails and reduce heel. This is great fun.

  • First Reef - When it is time for the first reef the life vests come on and the first hatch board goes in. This effectively doubles the height of the bridge deck.

  • Second Reef - We haven't experience condition that require this yet. But depending on how it feels either one additional hatch board goes in or we close the cabin up. In addition a locking pin goes in the sealed aft deck hatch.

  • Drop the Jib -Again no direct experience here. But this will be our last weapon as the condition worsen. The cabin will definitely be completely closed up. In addition I would likely tether myself to the topping lift for work on the foredeck in conditions that require this amount sail reduction.
One frustrating and nice thing about Bolero's cabin is that the hatch boards and sliding companionway have an incredibly tight fit. Certainly they aren't watertight but there won't be water gushing in and they aren't going to float away. Also the addition of Bolero's cabin created a cockpit with less volume. So Bolero will float higher in the water with the cockpit flooded than the Shields did in the above test. Hopefully that would create an easier baling situation.

Not the I have any desire to test this theory.