positive floatation

[roland cobine]

    just curious----i wonder if a compac 16 has positive floatation? if not can i possibly put some sort of airbag in on top of the bunks. im not planning on ever going over but since i only plan to daysail and dont need the bunks thought it couldnt hurt.

[KPL]

I think the floatation issue depends on the year.  I have a 1982 CP16, and there is a large chunk of closed-cell foam under the cockpit floor.  Between that, the foam under the berths, and the foam under forepeak, I think it has positive flotation.

That being said, I'm not sure what you'd do with a CP16 full of water.  It'd take a long time to bail out.  If you're lucky, you might be able to tow it to the trailer and slowly pull it out (with the plug out in the back).

I think the best bet would be to seal the lazerrette hatch, and keep the hatchboard in if you are in any kind of weather...

My 2cents.

Kevin

[Craig Weis]

Fill this boat up with water and she goes down.
It's the keel.
Way back when is one of my posts quoting the 'law' that does not require Hutchins to provide flotation. I asked Rich [H] about this at a boat show and indicated that with the keel on these boats, "You can fill them with ping-pong balls and they still will go down" a bit of an exaggeration but you get the idea. 
Of course the keel is what makes the boat so stable so who needs flotation unless you plan on driving a log through the hull below the waterline. skip.

[fiddlerami]

It seems to me that the amount of buoyancy needed to float any object is just a matter of some relatively simple math - maybe I'm wrong...
Here's my slant on it:

An air pocket, whether a balloon or foam, will provide buoyancy proportional to the weight of the volume of water it displaces.  One cubic foot of water weighs about 62.42 pounds.  If the Com-pac 16 weighs about 1100 pounds (I think thats pretty close) then 1100 divided by 62.42 equals 17.62 cubic feet, meaning that a volume of air equal to that volume would cause the boat to have neutral buoyancy.  Any larger volume would cause it to remain on (or very near) the surface.  It would not go to the bottom (or sink).  To use rough numbers to get a feel for the amount of foam needed to equal 17.62 cubic feet I visualized two blocks of foam measuring 1 foot by 2 feet by 5 feet which would yield 20 cubic feet.  That volume, by my calculations, would give positive buoyancy to an object (any object) weighing about 1248 pounds.  Is my physics bad?   - what say y'all?

[KPL]

Fiddlerami -

I think that's about right.  The block of foam under the cockpit (between the berths) is about 14X18X60 give or take.  However - check your math 1X2X5 is 10, not 20.  So my math shows about 600lbs of flotation.  Plus there is foam under the cockpit coamings. - but I still think it's enough to keep off the bottom. 

Flotation does not have to equal the entire displacement, just enough to keep it afloat (all that fiberglass displaces some water, maybe not it's weight, but a portion of it.)

Kevin

[Paul]

Hey guys.  I think Skip is correct.  Best way to "keep her off the bottom" is to keep her hatch shut in precarious situations.  Safety and fore-handedness comes first.  All that foam may seem like a temptation to relax, but it would be best not to tempt this fate.

Our boats are good little boats that stay upright most of the time.  I have read a much earlier post of a CP-16 sailor returning into an inlet when a wave broached her in the surf.  But, that is one incident.  Haven't heard of any rolls or pitch-poles and the like.  Just don't happen to these little boats.  However, sinking at the dock because someone left a hatch open during hurricane season, well...........that's more likely.    (no didn't happen to me, just making obtuse hypothetications.)(Is that a word?)  

No really, just keep her shut up tight and the mast upright and you don't have to worry about sinking.  The foam is there more for support than anything else.  Skip heard it from the man who knows.  That's good enough for me.

[Rick Klages]

Design an interior cabin "airbag" out of air tight fabric like life boat material.  Equip it with a lifeboat gas generator and an activation cord. Pack it in a self deploying bag on the bottom of the coach roof aft of the cabin light.  In an emergency yank the emergency handle.  Just don't be in the cabin when it inflates.  Should render your CP-16 unsinkable. 

ick

[roland cobine]

 gotta say im not planning on putting her over. but i always like it when she heels up a bit. these buggers might not be fast but you do expierence all the aspects of sailing. as always i do appreciate the benefit of this helpful group. thanks

[curtisv]

Rick,

Dive shops usually have or can order recovery bags used to float very heavy objects to the surface (like ATVs and snowmobiles that used to go through the ice around here in the spring).  Boats are usually refloated using these same bags.  If you were really worried about sinking you could bring an air tank and one or a few of these.

You can't really sink a compac on protected inshore waters by sailing it wrong or at least it would be extremely hard to do so.  With enough fetch you might be able to get a wave big enough to put her over but the CPs are rather hard to knock down let alone roll.

I've thought about positive floatation for coastal sailing since I've been about 30 miles from shore at times but I was thinking about filling unused storage space with structural foam until I thought a bit about the price of doing so.

Then again there could be a very high price for not doing so but I don't see it as a great risk.  Towing a dinghy at least provides somewhere to go if I were every to ram some floating debris out there and seriously hole the hull.  Otherwise I can't see how a sinking could occur if I'm careful not to get caught out in severe weather.  Sustained severe weather is predictable.

Roland,

This question come up from time to time but the real question is can a knockdown caused by the wind alone ever sink a CP.  The answer seems to be "no it can't" or at least no one has every done it and quite a few have tried (if unintentially counts as "try") even with the hatchboards out.  I'm sure it could be accomplished on the open ocean given a big enough wave and on some of the larger lakes out there with plenty of fetch.

Curtis

[roland cobine]

thanks for the input curtis. i think im a good enough sailor to keep her on her feet. my previous boat was a planing hull centerboard boat. but i never got knocked down in that one either. trapeze rig. the compac is the first keelboat ive ever owned. i was away from sailing for almost 20 years and was looking for a sailboat since i just retired. figure ill sail most of the time and fish out of my duracraft the rest. i was real lucky to get the compac. it was in the paper under "recreational vehicles" if you can believe that. the word "compac" jumped out at me. $16oo for an 81 with three working outboard motors, new tires and three reconditioned sails.i lucked out for sure. thanks again for the advice.

[Rick Klages]

I was joking of course!  I have no qualms whatsoever about the seaworthiness of my CP-16. I won't likely modify mine to carry more flotation. 

ick

[multimedia_smith]

Much has been discussed, researched, and written about this topic on the "other" Com Pac (yahoo) group.
Search for "flotation" at:
http://groups.yahoo.com/group/com-pac/messages
http://groups.yahoo.com/group/com-pac/
Bottom line is that no one has tested it, but the 16 is the only Com Pac that supposedly does have positive flotation... I think about stuff like "how would I get the battery overboard" and "would I tie a float and long line to the motor before letting it go"  but with the six extra life jackets and swim noodles, I don't feel the need to fill the remaining cavities with foam... in fact there is very little likelyhood of filling the hull unless you hit some serious rocks... and in that event... sinking is going to be low on your priority list.
I feel really secure in this boat having been out in really rough conditions and a couple of brief knockdowns... that's why I now have a storm jib and two reefed main.  If the boat is set up for the conditions... the hull is a great design.
Best to all
Dale

[Carol]

So, I can vouch for being able to have a LOT of water in the boat and still have it floating just fine.  At the end of the season the bow eye (which I had hooked to a pendant for mooring) came off completely while the boat was moored during a thunderstorm.  This left the two drilled holes which are barely above waterline open to the lake.  Fortunately the boat drifted to the shelter of our club's launch and the person on watch captured and secured it.  They called that nite.

The next day, armed with an electric pump, we popped the hatch and discovered water up over the bunks.  It was riding low but in no danger of bottoming out.  After the initial pump-out there was still water seeping from various hiding spots which we would then empty.  This ended after about two days.  Good thing I don't have cabin cushions :-)

That was a lot of water...so I'm not at all worried about sinking.  I am, however, making sure the bow eye is well sealed.

Carol.

[roland cobine]

 although im not planning to "test" my 16, like everyone else im happy to gain first hand information. one of the best and one of the worst things about sailing is the element of unpredictability.  we are more subject to the whims of nature than powerboats for sure. our best defense is knowledge, and with it confidence. these coupled with expierence lead to much pleasure on the water. as an inland lake sailor, i doubt ill ever expierence a knock down but i have sailed in some pretty good gusts and like all sailors learn with each sail. im hoping that with the coming of spring my boat "kickinbug" will spend most of her time on the water teaching me. thanks again carol for sharing your expierence with us.

[curtisv]

That was a lot of water...so I'm not at all worried about sinking.  I am, however, making sure the bow eye is well sealed.

Carol.

Carol,

The bow eye isn't intended to be used for mooring.

Anyway the bow eye on my CP23 was starting to pull away from the stem, maybe 1/8 inch or so.  I removed it (while the boat was on the trailer of course, not in the water) and put about a 3 inch length of one inch bay 1/16 inch aluminum as a backing, then used plenty of silicon caulk (would have used polysulfide but its above waterline and I was out of that) and tightenned it back down.  Won't budge now.  There is no substantial backing in the factory install, just small washers on wood.

Curtis