Ha Ha Ha Tomo , I haven’t had this much fun in a long time. As Angus notes, I think those guys have that figured out by now. The point I was trying to make in the reference to “blue Dow” is to specify an EXTRUDED polystryene which is totaly water resistant, as opposed to an EXPANDED polystryene which can absorb water over time. Common white 'beadboard" will soak up water like a sponge.
I did the math to determine how much volume is needed to float an ODOM (7# 4oz) & came up with a bit over 200 cubic inches, which is roughly a 6" cube.Feel free to check the math. This would be tough to get in, even cut up. That’s why I really like Dick’s inflatable bag idea. It would probably be lighter too. The jib sheet would need to be covered or moved.
Of course (as noted by others) the key is to keep water out in the first place. I learned this from personal experience when my Fairwind sailed away from me on one of the larger area lakes. It was windy with an offshore breeze & a decent chop. Needless to say, my deck was not taped & quite leaky. I was just heading it back to the dock to drain when the electronics totally went out. I figure the water got high enough inside to get to the batteries or the receiver. Anyway, the sheets went slack & it started
on a broad reach to the far side of the lake over a mile away. After scouting the immediate shore for a rescue boat, I jumped in my car to go over to a friend’s place to use his power boat. We searched for quite a while, but I think it had sunk by then. I really missed it for some time as it was my first “real” rc sailboat, with laminated teak veneer decks & some other nice features.
6 inch cube = 216 sq in (3540cm^3 or 3.5 kg/7.8 Lbs) That seems like a lot of cubes. If a ping-pong ball is 2 cu. in., then you’ll need 108 of them (still seems like a lot!)
ummm ---- the 7 lb. 4 oz. figure Bill was using is total weight/displacement of the ODOM (class minimum sailing weight). If this is correct (ODOM specs) that quoted weight floats the boat at it’s designed waterline which provides several inches of freeboard and the entire mast/rig above the water. :rolleyes:
You can reduce the 6 cubic inches to get the hull to float at the “surface” of the water, since the premise was the boat had swamped (or started to sink), and the hull would be full of water (less some air pockets - difficult to calculate without measurement) and the idea was to “prevent the boat from sinking” - not to bring it back up to it’s designed waterline and sailing trim with 2 or more inches of hull, deck and rig above the water. In fact, one would only need enough foam to keep the top few inches of the mast projecting above the top of the water surface until the boat was rescued. I assume we would agree that regardless of how deep under the surface, it would not be able to be sailed back to shore, considering it was full of … ohhhh — nevermind. :banghead:
Unless you’re going to be diving into the water, you’ll need some kind of hook on rod. A hook on a line with a weight would work, but it’s hard to aim. I think your attack plan depends on the depth and what’s on the bottom. On a soft bottom of silt would I’d use a rod & hook, like for golfball retrirval) to drag the bottom. If there’s vegetation, sticks, rocks, etc., you’ll need to get picky and (again) use a rod & hook setup to poke around; hopefully, you’ll be able to look into the water to locate the boat. The line & float helps in location; just follow the line to the boat.
You can use a big tube (like 6 or 8 inch PVC pipe) to look under the water by immersing one end into the water to smooth the ripples out. If the water isn’t to cloudy, you may be able to see to the bottom on a sunny day.
No Tomohawk. What the nice man is saying is that if some of the boat (not very much) is above the water, you won’t havre to go diving for it (unless you’re an eagle). With a bit of luck you can then retrieve it (i.e. pull it in to the bank) by all kinds of methods. Some may involve a pole, line or hook, but none require any need to look under the water. This is because, lo and behold, SOME OF THE BOAT CAN BE SEEN ABOVE THE WATER.
No Tomo. If we understand the physics, above the surface. In order to be ‘just below the surface’, it must be neutrally bouyant (i.e. weigh exactly the same as the water it displaces) unless it is actually sitting in the bottom. In the latter case, the problem is academic: you wade.
To is impractical to predict a neutrally bouyant solution: apart from anything else, the density of the water changes with temperature as does that of any trapped air bubbles. Therefore we have to go for a positively bouyant (i.e. out of the water) solution.
The constraint is that the boat is at the bottom. No discussion necessary about how far below the surface the boat is. And as you can plainly see, the buoyancy of a boat doesn’t answer the question. Somehow we got off on a tangent involving foam and buoyancy.
IMO, Dick’s suggestion is to prevent a boat from becoming neutrally ( or less) buoyant, so it doesn’t have a chance to submerge. Perhaps he would want to clarify this.
The other constraint is that this person doesn’t want to go wading. He would like to discuss (on-board) retrieval equipment.
Can we get back to the topic? If you wish, we can ask this person to rephrase the question.
You kind of prepare for it, or react to it:
… either one adds something to keep it close to the surface so you can see about 1 foot of sail (above the water) — called preparation/prevention, - or one does as Neil did - get a diver to go down and look for it - called reaction.
Underwater fish-finding TV, sonar, etc, might be possible, but probably kind of expensive for a one-time use. And you still need something to get out to it to retrieve.
I didn’t catch on to your suggestion at first, but you’re right Dick, this is the ticket. Maybe just attach it to the deck (like a liferaft) with a line.
No foam required, and it should easily attach to the reel I was working on using, which is just an empty cotton reel with about 40 metres of 50 lb kevlar line on it.
I just need to attach the line to the boat somewhere and Bob’s ya Aunty’s live-in lover.
