Tim Diebert Posted February 12, 2003 Posted February 12, 2003 I am going to be doing a bunch of work to my boat soon and was planning on adding some floatation. With all the crap I am prone to hauling around...not to mention a 6hp Johnson...she will sink like a stone I am sure. This is something I am thinking I may like to prevent. Wondering what have you folks used and where? I have the spaces in behind the bench backs that is not being used for anything on my boat. I was thinking of stuffing those areas with cut off pool noodles. I am going to need something up front so the boat floats level when swamped. This is where I am coming up with a blank. Any ideas? Does that 'spray out of a can foam stuff' work as floatation? Maybe the forepeak...but I am not too keen on that one as I hate to prevent the eventual access of any area for through bolting and repairing. Cheers, TT www.timtone.com Quote
JMetzner Posted February 12, 2003 Posted February 12, 2003 Tim, I packed the seat back area with blue foam board insulation. I haven't done the forepeak yet, but I heard of others gluing layers to the back of the forward bulkhead and the bottom of the deck above the forepeak. Also, some pack the forward portion of the forepeak. John M. Quote
Arnie Eaton Posted February 12, 2003 Posted February 12, 2003 Tim, Don't use the spray can type of foam. It will absorb water. The blue stuff works OK. Quote
Barry Pyeatt Posted February 12, 2003 Posted February 12, 2003 Tim, The spray can foam is a real problem in this application. One of the easiest things to use is plastic milk cartons. They are essentially free and they can be shaped (to a degree) to fit in the areas and obviously they are an enclosed air chamber that will float. If they are punctured, then they obviously won't work any longer but they are easily replaced. I would personally use the "Blue-board" closed cell insulation board and cut it to fit against the bottom (underside) of the deck in the forepeak and attach it with velcro. If you need to remove it then it comes out easily, but it isn''t going anywhere when it is wedged inplace. Layers of it can be cut to shape for the area behind the seats and in the lazerette. Small pieces of velcro will hold them together and still allow them to be removed if you need to work in the area. Another area that can use it is the side decks inside the cabin area. It can be covered with other material to finish it off and secured the same way (with strips of Velcro to the underside of the decks. I have also seen pieces cut to fit between the rafters and covered with material and then placed against the ceiling. You wouldn't even know they were there until told. Same thing with the hull sides, the foam can be cut to fit and covered and fitted into place. It also adds a great deal to the sound deadening and thermal insulation qualities of the hull. The bottom (floor) of the cabin can have closed cell pads covered and placed down on the floor. When "camping out", it will make it a lot more comfortable, and if the boat needs some flotation, it will help. I would be very reluctant to permanently adhere it to any of the plywood surfaces however. Hold it inplace with straps or velcro or wedge it to fit. :roll: : Just something to think about. Quote
Stuart Benbow Posted February 12, 2003 Posted February 12, 2003 Just a question ... I know that under normal circumstances, velcroing or taping or placing flotation in place is fine, but if the boat floods, the isn't the floatation now holding up the boat instead of the other way around? Wouldn't you need something a little more substantial to keep the floatation from moving, like sealing it in an area of the boat? As to the milk cartons/pop bottles and other ideas people have proposed, has anyone tested these to see if the caps can withstand the pressure of holding up several hundred pounds of boat, people, and gear without blowing their tops? I'll be at the point of installing floatation in another couple of months and would like a sure-fire way of getting it right the first time. Just curious to see if anyone's actually tested these solutions or what? Quote
Guest ken connors Posted February 12, 2003 Posted February 12, 2003 i considered the pressure on those milk bottle caps and decided to silicone the caps to the jugs. ive heard some say they hot glued the plastic containers together to make sure they dont jostle around Quote
Bill Paxton Posted February 13, 2003 Posted February 13, 2003 I used empty milk jugs behind the seat backs. Since my Weekender is cabinless, the seats are long, and I got a lot of flotation out of it. I used hotmelt glue to secure the caps to the bottles. I also secured the bottles (so they won't rattle around) by looping a plastic strap through the jug handles, and screwing the strap into the bottom side of the deck. I chose this option since it seemed least likely to trap water vapor and cause rot. Quote
Barry Pyeatt Posted February 13, 2003 Posted February 13, 2003 Interestingly enough, two-one gallon milk jugs will provide flotation for a 200 lb person. It doesn't take that many to provide neutral/positive flotation in a boat the size of a Weekender or even a Vacationer. Lots of the caps are screw on, but for those that are press on, just use a little duct tape around them and they will stay put. I have seen them used rather extensively in small boats for just that purpose. In an enclosed area they stay put pretty well if the area is filled with them, ie. behind the seat backs or in the lazerette. We never crushed or disposed of the empties on any of our larger boats, we just put the tops on tight and stowed them for additional flotation for the duration of the cruise. They also came in handy to store fresh water. One liter soda bottles work quite well in smaller areas. If you want a heavier duty container, then use liquid laundry detergent containers, they have good tops and hold up well. They can be taped together with the good ole standby (Duct tape). :wink: Quote
Tim Diebert Posted February 13, 2003 Author Posted February 13, 2003 All Excellent advice as always. Thanks folks. I now have a plan. Barry! Welcome back Dude. Howz the peeperz? Cheers, TT Quote
Barry Pyeatt Posted February 13, 2003 Posted February 13, 2003 Tim, The eyes are getting better every day. Double vision is nearly gone with corrective lenses. Healing is progressing nicely. The warm air and tropical waters don't seem to be doing me any harm either. Will stay here thru Feb and part of March and come home then. Thanks for asking. Quote
Russ Sylvester Posted February 13, 2003 Posted February 13, 2003 Another option that I used and seems to have worked out quite well is to use foam. Home Depot sells expanded polystyrene in 4x8 sheets about 3 inches thick for about ten bucks. This is the same stuff that is used as insulation in Igloo type coolers. It is fairly rigid and is really easy to cut with either a hacksaw blade or a sharp utility knife. There is a construction adhesive that will work specifically with this foam. DON"T use just any old glue as most of them will eat the foam and leave you a big mess. Read the label carefully. For the seat backs I simply rough carved out some pieces and then glued them into place to keep them from moving around. I also put two layers off foam under the deck in the forepeak area. I just used the dimensions of the deck from the plans and glued them under the deck. I don't expect that it will keep the boat totally floating but my hope is that I can at least right the boat after a blowover and at least get the gunwales out of the water. I can then bail it out from there. Something to think about. Quote
Brent Posted February 13, 2003 Posted February 13, 2003 I am thinking a plywood and epoxy boat will be negatively buoyant...that is if the boat is filled with water it will sink. I haven't tested this, but get this impression from the density of plywood panels and epoxy resin. These expanded foams come in different densities. Usually the stiffer the foam sheets are heavier, therefore it takes more stiff foam to float a boat than the softer foams. Generally expanded sytrofoam sheets have a floatation capability of 40-60 lbs per cubuc foot. A gallon jug has a floation capability of 8.3 lbs. Maybe one of the nautical engineers amoung us could expound on how much floatation it takes to get the gunwales out of the water. Quote
Tim Diebert Posted February 13, 2003 Author Posted February 13, 2003 Barry. Good to hear from you. Live must be tough in HI...but hang in there, man. Ray...excellent info. Thanks. So if you know how much the milk jug displaces...do you then know how much weight the foam boards will hold up? ...or will that info be provided by the foam supplier? No matter I guess, I will just fit as much of the stuff in there as I can. Also Ray, did you find the line drawings you were looking for? I noticed Phil Gowans has some on his site. I think he drew these up himself. Quote
Barry Pyeatt Posted February 13, 2003 Posted February 13, 2003 Yes, we are trying to displace water with air to provide a positive buoyancy and two one gallon milk cartons will provide enough positive buoyancy to keep a two hundred pound person neutral to slightly positive in salt or fresh water. No...it will not float them above the surface. We are trying to provide enough flotation to keep the boat from sinking, it doesn't take all that much to accomplish that. In an emergency a pair of pants with the legs tied in a knot at the ankle and simply pulled tight at the waist with air inside will support the average person and keep them from sinking. This is one of the life saving techniques taught in many areas. The amount of air captured in the pants isn't much more than provided in a pair of milk cartons and fortunately the air stays in the milk cartons better than in a pair of pants upended. These boats will sink because of the added weight of the glass, paint and the extras that are added to them. But the boat itself is relatively positive in its ability to float, even when filled with water. Add something such as a closed cell foam or even several sealed bags of air and the boat will stay afloat even when filled to the gunnels with water. Enough to support a person, but not keep them high and dry. Just remember that any foam has to be closed cell, not open cell. I have seen lots of people use upholstery foam and think it will provide flotation, but it is open cell foam and it soaks it up like a sponge. Same with most of the foams used in packaging. The best flotation comes from a closed, sealed area without anything in it. (A flotation chamber) Ice chests when empty are wonderful, and in an emergency, empty the contents and close it up, it adds a lot of buoyancy. Even closed zip-loc bags filled with air help. I saw one small 16' glass sailboat boat floating at its rails and when pulled out and the water dumped out of the boat the chambers under the edges of the deck had been filled with foam peanuts from packaging, and they were packed with them in plastic bags. The total amount of area was roughly equavalent to 4-5 milk cartons worth of area. It provided enough additional buoyancy to keep the small cabin top and hand holds above water and the three persons alive until they were picked up. Quote
Tim Diebert Posted February 13, 2003 Author Posted February 13, 2003 See...that's what I was thinking Barry. I figured one of those wee pool noodles keeps me afloat when I playing around with one in the Lake...so a bunch of them might keep the boat from a trip to visit Mr. Jones....and the added bonus being that you will never have a shortage of Lake toys for whatever kids...big and small....that show up. Milk Jugs are sort of free and you would be recycling as well. Maybe I'll just drill a series of holes around the perimeter of the boat...through the toe rail and lash a bunch of milk jugs on there. It would be fashionable and effective boyancy as well. :roll: Quote
Russ Sylvester Posted February 13, 2003 Posted February 13, 2003 A cubic foot of displacement is a cubic foot displacement. I don't care if you do it with air or concrete it will still displace a cubic foot. The only difference is how much the material that you're doing the displacement with weighs. Obviously a cubic foot of air will weigh less than concrete. Let's assume for a moment that a cubic foot is two gallons of water (Yes, I know it isn't but I don't have time to look it up at the moment). Let's also assume that one cubic foot of foam weighs about a pound. Two gallons is roughly 16.5 pounds of weight. If I displace that much with my one pound of foam then I still have 15.5 pounds of bouyancy, if it is fully submerged. So I have to ask, are milk jugs going to net that much more bouyancy than foam? I don't think so. Quote
Tim Diebert Posted February 14, 2003 Author Posted February 14, 2003 I think, Ray, you should volunteer your time and your boat to test your theory. I am sure we would all like to know this very important piece of buoyancy information. I figured you could just swamp the boat, see how high she floats...then slowly add bits of gear to bring up the weight....don't forget to include yourself....and then let us know at what point your boat....sinks. Then we will have a solid guideline from which to determine the floatation required. Simple. Don't forget your camera! Quote
capt jake Posted February 14, 2003 Posted February 14, 2003 oh heck!! In our area, I rely more upon a good life jacket and a clear view of the shore!! :D LOL Just me!! Quote
Tim Diebert Posted February 14, 2003 Author Posted February 14, 2003 Man...that's cold. My condolences. I already have foam behind the seat backs you see, and I plan on adding some more under the cockpit seat as well as in the forepeak area, Dang....I just knew there would be hook :cry: So are you still thinking of adding 'half bulbs' to the sides of the keel? I also plan to do this (as we have discussed) but was thinking of going to the trouble of making a mold for a shape that will let into the keel. Also 200#. I have the lead...and a buddy who has a electric babit melting pot. My problem is I have not gotten much done on my boat over the winter and may not get to the ballast this spring. It is going to be quite a production on a finished boat. Be a lot more convenient if a guy was building from scratch. It would be easier upside down as well... I hope your system works out well...can't see why it wouldn't. It would sure be a lot easier to just add 'cheek pieces'. Quote
Tim Diebert Posted February 15, 2003 Author Posted February 15, 2003 hahahahahah. I just changes my avatar and they ALL change, not just future ones. Now I see my mug repeatedly when I scroll down this thread. Geez, I just realized how little it takes to keep me entertained RAY: You are some knowledge filled rascal aren't you? All those numbers and factoids. Last time I went to see my machinist I asked him if he had any lead. He had a couple of ingots that he said weighed about 80 lbs each. One of these puppies looked to be about 2 1/2" square and maybe 14" long....so I figure 200# would have worked out fine. But I guess not. In my case, I do have a guide setup on my first roller to align the keel when retrieving...and MAN, did that ever improve life. I was hoping not to do anything to mess up that good thing....hence the let in ballast. I shall return to the drawing board. Quote
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