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Legacy positive buoyancy?

Started by Pete H, November 04, 2012, 01:00:18 AM

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Pete H

 Hi Guys,

I recently purchased a new Legacy and have been wondering about the amount of foam buoyancy fitted. I did try making a guesstimate of it but because of all the irregular shapes I couldn't come up with a reliable figure.

I really have two questions, 
                                        1: if I manage to put a hole in the boat will it float or sink?

                                        2: if it has enough foam to float, will it float right way up or inverted?

Any ideas?

Pete H
Pete H
Muggler (Compac Legacy)
Victoria
Australia
" Nothing satisfies the man who is not satisfied with a little".   Epicurus 341 BC-270BC

skip1930

Fills with water, down she goes. No requirement or law to make her float when awash. Not with keeled and ballasted hulls. There might be a change with a centerboard hull, If you want an unsinkable sail boat buy a French Made ETAP.

Like a Com-Pac 19 it could be filled 100% with expanding foam and the cement and pig iron ballast will still pull her under.

skip.

Pete H

Hi Skip,

Thanks for your thoughts. Sinks like a stone, yep that tends to concentrate the mind and is one of the things I have been wondering about.

As you say there is no legal requirement for buoyancy to be fitted and I'm sure you're correct for the U.S. however in Australia there is an NMSC (National Marine Safety Committee) requirement for all boats built after 2006 and less than six meters (20 feet) in length to have positive bouyancy fitted and for the boat to float level and upright when awash.

A Legacy fully equipped probably weighs about 600 kilograms (approx. 1300 pounds), so needs about 0.6 cubic meters of buoyancy material (about 20cubic feet I think) to provide enough flotation to counteract the sinking effect of the boat's hull, deck, ballast, motor and other equipment.

The Legacy has a lot of foam in the hull, in front of the forward storage, across the hull under the cockpit floor, the area under both bunks is completely foamed as are the comings down the quarter berths.

This is a new boat and should be built to meet the NMSC requirements to be sold in Australia and I'm sure it is, but I did start to wonder, then I started to try to assess the bouyancy, but because of the complex shapes I couldn't be very accurate. I was hoping that someone with a better sense of spatial relationships may have already checked or worked out the amount of foam fitted.
But if that is not the case, then I guess I have two choices:
                                                                                      1: hope that the foam fitted is sufficient

                                                                                      2: try to do a more accurate assessment myself. If I have to do that I'll
                                                                                           Post the results here for future reference.
Thanks for your thoughts Skip,
Regards and fair winds and calm seas

Pete H.
Legacy in Oz.
Pete H
Muggler (Compac Legacy)
Victoria
Australia
" Nothing satisfies the man who is not satisfied with a little".   Epicurus 341 BC-270BC

Bob23

Pete:
   You have a third choice: Don't fill the cockpit with water! I've often thought about enlarging the cockpit drains on my 1985 23/2 to at least 2 inches. If the cockpit floods and doesn't drain in a few minutes, the next wave could sink the boat.
   Keep the drop boards in and you'll prevent water from entering the cabin. Once that happens, things can to from bad to worse very quickly. Do you have an electric bilge pump fitted? In my humble opinion, that is a must. If the boat can bail itself, it'll free you to tend to other important duties.
   Just my $.02- Bob23

Pete H

Bob23,

Thanks for your thoughts.  No, I don't as yet have an electric bilge pump fitted, but it is up the top of the list of things still to be done.
  Cockpit drains! The cockpit drains on my last trailer sailer were 2 1/4 inches, those on the Legacy are about 1 1/4 add in the low transom and I have something else to wonder about.  Perhaps it's old age, I'm sure I didn't even think about stuff like this when I was fifty years younger. Perhaps I'm too old fashioned, when I had a look at a new Eclipse it didn't have at ransom at all, then the first thing I thought wasn't about the cockpit drains, it was, if I dropped something it would roll straight out the back.

Too much time on my hands, better go sailing!

Regards,

Pete H
Pete H
Muggler (Compac Legacy)
Victoria
Australia
" Nothing satisfies the man who is not satisfied with a little".   Epicurus 341 BC-270BC

skip1930

#5
" however in Australia there is an NMSC (National Marine Safety Committee) requirement for all boats built after 2006 and less than six meters (20 feet) in length to have positive buoyancy fitted and for the boat to float level and upright when awash. "

I think the U.S. has something like that but it does not apply to sailboats.

I see what happens when government gets heavy handed and imposes strict standards? Suppose what a better design the boat in question could have without all that extra foam [20cubic foot in a 18 foot long boat] taking up valuable interior space and only adding extra weight. Next they will require sailors to wear protective head gear...something batted about in California from time to time.

Life is dangerous. Let's not make it idiot proof.

skip.



Salty19

#6
Hi Pete!

I imagine the Legacy would sink if holed.
Further, I can't see putting enough foam in there to keep it upright.  There would be little room for anything else.

As a general rule, all of the small Com-pacs are not at risk of capsizing without a large breaking wave on the beam helping to overturn it. They will round up and spill air in high wind conditions keeping the keel down in the process.

If you plan to go out in conditions like this...I'm speaking of 8-10 ft breaking waves, you're sailing the wrong boat.

Personally I would invest in a good personal floatation device (with strobe, whistle, maybe a radio) and tether before messing around with foam.  If you're in bad enough conditions to sink the boat, you'll be in dire straights as well.

A bilge pump is a great idea.  Been meaning to install one.  It will probably sit unused (no thru hulls and our lake doesn't create big waves) as an insurance policy.

P.s. Congrats on the Legacy...very nice little boat!!!
"Island Time" 1998 Com-pac 19XL # 603

Craig

I am a little confused(and no offense meant)by the concept that all boats should be by law or whatever be rendered "unsinkable". Are cars supposed to be "uncrashable"? For me, at least, the lure of sailing is about pitting my skills against the elements and accepting the risks associated with taking my boat to sea. For uncounted years sailors have been doing just that. The pride of calling oneself a Sailor is that we accept the risks and set forth upon the water in spite of those risks. A pilot who flies an aircraft accepts the risks. If he fails, he may die. One who flies an RC plane only risks the loss of his toy. Not a great analogy perhaps but sailing is by definition a complex endeavour fraught with a myriad of choices and consequences. To sanitize it would somehow lessen the gut level appeal and responsibility of captaincy. Just an old salts opinion and worth what you paid for it.
Craig, Horizon Cat "Kailani"  Punta Gorda, FL

Bob23

Good word, Craig. And very true.
To make something completely safe is to take the life out of it.
bob23

Pete H

Hi Guys,

Thanks for all your input. We certainly have a range of opinions. Some of them totally contrary to others. In
an attempt to get a definitive answer I emailed Hutchins Co. and this morning I received a reply from Gerald L Hutchins. I tried to copy and paste it here but was unable to do so.  So I will prĂ©cis it here.

Hutchins said that when they redesigned the CP 16 they wanted a boat that was dimensionally the same, but wanted it to perform better, " and we wanted it to have positive foam flotation, not level flotation as powerboats are required to have but, enough that it would not sink." (exact quotation)

Hutchins believed that the National Marine Manufacturers Association would certify the Legacy for flotation. When the Legacy was all ready to go for inspection he learned that the NMMA follows the national standards  and there will not certify flotation in a sailboat.

Again an exact quote .." So, here we were with a boat that by OUR calculations would float but with no authorative body to certify it"
" It is still built to the specs that we believed would provide flotation for the boat alone, not considering equipment, supplies etc."

There is a fair bit of other info and if any would like a copy of the letter I would be happy to email the complete thing to you.

So... That's me satisfied on this topic.  Also, what great service from Hutchins Co. when the Boss himself quickly and completely takes time to answer a query from a customer.
Pete H
Pete H
Muggler (Compac Legacy)
Victoria
Australia
" Nothing satisfies the man who is not satisfied with a little".   Epicurus 341 BC-270BC

skip1930

Put enough foam in the boat so it won't sink...will the deck 'let go' from the hull anyway?

Just asking. skip.

Bob23

Thank you Pete. That is very interesting, indeed!
bob23

Pete H

Ah Skip,

I wish you hadn't said that, you've given me something else to worry about.

Pete H
Pete H
Muggler (Compac Legacy)
Victoria
Australia
" Nothing satisfies the man who is not satisfied with a little".   Epicurus 341 BC-270BC

Bob23

Pete:
   Skip is right. I'd be concerned about that...I imagine it wasn't designed to withstand uplift. Sounds like another call to Rich Hutchins is in order!
bob23

BobK

Pete,
Over the last 40 years I have sailed around 15k - 18k miles on boats that will not float.  I did not sail 1 mile on a boat without a suitable life jacket aboard.
BobK