Monday, November 26, 2012

When Is A Vessel "Overloaded"?

Estimating A Safe Passenger Load
Article by William L. Gills aka Bos'n Bill

It was the Fourth of July, a clear calm evening, chance of thunderstorms in the forecast when Kandi Won, a recently purchased 1984, 34-foot Silverton motor yacht set out from the Swawanhaka Corinthian Yacht Club with 27 passengers and crew to watch the Oyster Bay fireworks.  Anchored among the hundreds of boats, they came to watch a thrilling display of vibrant colors exploding in the night sky, mirrored on the bay, accompanied by sonic booms, their echoes reverberating off land, across water and the surrounding boats.  This is what they came for.  It was spectacular!  

It was almost 10 p.m. when Sal Aureliano started Kandi Won's engines after the grand finale.  It was time to return to port so the kids could get to bed at a decent hour.  3 of the 10 children aboard went below for the ride home; 17 adults standing and sitting on decks with the remaining children . 

Maneuvering slowly, carefully navigating the over crowded course home, the skipper became distracted by two successive lightening bolts 10 minutes into the cruise.  Suddenly, mysteriously the boat started turning on its own.  It felt as though the Silverton was under the influence of a rogue wave, the rudders rendered useless.  Sal couldn't see what was preventing him from righting the course of the boat, it was too dark.  Listing slowly evermore to starboard the motor yacht suddenly tipped over to the right, throwing its passengers over the rail into the water.   

Sammy Balasso put the spotlight of his 38-foot speedboat on the capsized vessel and threw all the life jackets he had into the water.  He was able to rescue 20 people.  Other boaters in the area also assisted in rescuing passengers.  In spite of attempts to rescue everyone, tragically, the bodies of 3 children; a boy aged 12 and two girls aged 11 and 8 were found some time later, two obviously trapped in the cabin when the boat capsized and took on water. 

Scott Menzies had positioned his 20-foot motor boat in the area to take in the celebration but didn't see the accident, telling authorities conditions on the water were calm during the fireworks and afterward. The National Weather Service said a thunderstorm moved through the area about 20 minutes after the first 911 call,  but winds never exceeded 10 to 15 mph.

So if weather didn't cause the mishap, what did?  One would be correct to assume that the boat was dangerously overloaded with passengers, but was it illegally overloaded?  No, the Coast Guard doesn't set maximum-capacity limits for yachts over 26 feet long even though overloading may make a boat unsafe and difficult to handle.  Coast Guard rules only require there be a life jacket for every passenger aboard and for children to wear them at all times except when in a boat's cabin. 

The investigation is still ongoing and no conclusions have been reached as of this writing.  Weather, overcrowding, the wake from another vessel or a combination of factors are still under consideration.  Alcohol has been ruled out.

Phil Cusumano, a safety instructor and yacht captain with 35 years of experience expressed his opinion about the tragedy.

He said, "There is no question the boat was badly overloaded. I would limit a vessel of that size to 6 adults.  Other boating sites suggest a maximum of 15 passengers.  27 is just crazy!  I wouldn't dream of doing that.  I wouldn't do it at the dock, much less take it out on the water.  It would tip over with the first turn."

Nothing could be nearer the truth, as this is what actually happened to the Kandi Won with a little help perhaps from someone else's wake, cross chop or unbalanced weight distribution. 

When is a vessel overloaded? What are the rules? How are you supposed to know the capacity of your boat?

The simplest way to know is to look at the manufacturer's maximum rating plate on the transom or near the helm or cabin.  It will give you information relating to the maximum cargo capacity, the horse power rating of the motor that powers the boat and the number of people the boat can carry safely. Single hulled vessels in the United States under 20 feet in length are required to have a capacity plate.

The manufacturer determines the maximum cargo capacity by taking into account the maximum weight of passengers, plus goods and equipment allowed for recommended safe operation of a vessel.  Weighting a boat beyond the maximum rating and you run the risk of being swamped or capsized. 

The same considerations apply to larger vessels however,  it's left to the judgment of the skipper to determine a safe level of operation;  there is no magic formula to determine exactly how many passengers are too many. But, if you can determine the maximum number of passengers allowed as suggested by the Coast Guard Auxiliary for smaller boats, then subtract from that number the weight of fluids (water, waste and fuel), goods and equipment you should have a pretty safe idea of how many passengers would exceed the maximum for your boat.

The rule of thumb for determining the maximum number of passengers for smaller craft is to multiply your vessels length by width and divide by 15 (L x W / 15).  Length is easy to derive, it's a measurement of your boat's overall length.  You'll find it in the manufacturer's manual under boat specifications or measurements.  Determining width is a little less straight forward on a larger boat in that you should account for the angle in- toward-the-bow.

To roughly determine the square footage of a larger vessel, measure your boats length and width to the point where the boat angles in-toward-the-bow. Calculate the square footage (L x W).  Then measure, the length from the point where the boat angles in-toward-the-bow, to the bow and multiply times 1/2 the width from that point forward (L x 1/2 W). Add the two calculations together to get the total square footage, then divide by 15.  That is (L x W) + (L x 1/2 W) / 15. 

Take for example, a 30' boat with a 10' beam and a measurement of 20' before the boat angles in-toward-the-bow. It would be calculated as follows:  20' x 10' = 200 sq. ft. (L x W).  The next 10 feet  would be calculated as 10' x 5' = 50 sq. ft.  (L x 1/2W).  The total of the two calculations of 200 sq. ft plus 50 sq. ft. = 250 sq ft.  Dividing the total square footage by 15 gives you a 16.6 maximum passenger load.  But, don't stop there and assume 16 to 17 passengers is a safe maximum.  You need to account for fluid weight (the weight of water, waste and fuel) goods and equipment which can be quite heavy when fully loaded.   These factors should be subtracted from your maximum passenger load.

Water and waste weigh over 8 pounds per gallon, but let's round off to 8 pounds to keep it simple.  Gas weighs about 6 pounds per gallon.  Using the example of a 30' boat with holding capacities of 40 gallons of water, 10 gallons of waste and 160 gallons of gasoline we come up with the following:

Holding Tank
No. Gallons
Total Weight
8 lbs/gal
320 lbs
8 lbs/gal
80 lbs
Fuel (Gasoline)
6 lbs/gal
960 lbs
Grand Total

1360 lbs

So far we have a grand total of 1360 lbs.  Remember though we need to factor in goods and equipment, i.e., the other things you stow on the boat like anchors, cleaning supplies, coolers, ice, beverages, food, life vests, lines, bedding, duffle bags and fishing equipment.  Use your best judgment on this, but for the sake of the 30' example let's apply an additional 200 lbs to the 1360 lbs of fluid weight, totaling 1560 total extra pounds toward a safe passenger load.

Next we need to translate 1560 lbs into people weight to be subtracted from the 16-17 maximum passenger load calculated above. The U.S. Coast Guard Auxillary assumes and average weight of 150 lbs per person in its formula to find the number of people a boat can carry.  1560 lbs divided by 150 average people lbs would make 10.4 people.  Subtracting 10 from 16-17 maximum passenger load would give you an estimated safe passenger load of 6-7 adults including the skipper.

Of course, there's no substitute for experience. With time and experience you learn what safe feels like.  If your boat is leaning too much to port or starboard, your stern is digging deep in the hole, you're down too low on the bow plowing ahead, your planing hull is slower to get up on plane, you're sitting much lower in the water than usual, you've lost some maneuverability, then maybe your vessel is "overloaded".  For those that don't know for sure or don't know what that feels like, estimating the safe passenger load for your boat ought to give you some peace of mind and ensure safer passage to and from your destinations on the water and prevent Kandi Won like tragedies.  Take the time to do the math.  It just might save an innocent, trusting life.

William L. Gills aka Bos'n Bill, webmaster of this site, is the author of the book Lubber's log, published by Llumina Press; a boating journal and adventure story of the author's first time experiences in the preparation, maintenance and piloting of a new, unfamiliar boat. You can visit his website here.


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  2. Sometimes overload is dangerous it is very risky.I highly suggest that boating is fun but without making it risky.Thanks..