DrWatson 375 Posted May 29, 2012 Share Posted May 29, 2012 I was looking through the Cat 0 and Cat 1 rules and can't seem to find any mention of the requirement for a watertight collision bulkhead. Is it still a requirement? Am I just not looking hard enough? Link to post Share on other sites
tuffyluffy 76 Posted May 29, 2012 Share Posted May 29, 2012 I thought it was only a requirement for Cat 0, not so for Cat 1. But as my GF reminds me, im regularly wrong. Link to post Share on other sites
Variant 2 Posted May 29, 2012 Share Posted May 29, 2012 It seems only "Motoryachts" (cat 1) and Multihull yachts (cat 1,2) need them. Here are some quotes from the regs. Motoryacht INSPECTION LIST 1.0 (d) Hull and DesignMinimum of two water-tight bulkheads - one collision bulkhead forward plus one other. And for Multihull yachts 7.6 (M) Any hull in which there is no living accommodation shall have at least two water-tight transverse bulkheads and the distance between the two transverse watertight bulkheads shall not exceed 4 metres. 7.7 (M) All multihulls shall have a water-tight bulkhead between 5 and 15% of the vessel’s waterline length from the bow. 7.8 (M) All hulls of multihulls shall have sufficient inbuilt buoyancy or sufficient water-tight transverse bulkheads to ensure adequate freeboard and stability in the event of any one compartment being flooded. Transverse water-tight bulkheads other than collision bulkheads may be fitted with water-tight doors. The regs also mention bouyancy required for trailer yachts when swamped of 9Kg per person. Link to post Share on other sites
DrWatson 375 Posted May 29, 2012 Author Share Posted May 29, 2012 Yeah, That's all I found too. I for some reason thought it was also for monohulls. For Ocean cruising I'd definitely want a few water tight compartments. Hopefully with enough reserve volume to account for the mass of your boat. Link to post Share on other sites
Variant 2 Posted May 29, 2012 Share Posted May 29, 2012 Yeah it would give some peace of mind. Have you heard of Etap yachts? http://www.etapyachting.com/ Link to post Share on other sites
Terry B 71 Posted May 30, 2012 Share Posted May 30, 2012 I'll have an ETAP 32 thanks. llluuuuurrvve that interior! Probably sails well also......... Wish I had the money........... (going into blissful dreamtime now) .................. lotto win........................ ...................no more work............................. . Sorry, now back to the real world. Nothing to see here. Move along. Link to post Share on other sites
ScottiE 174 Posted May 30, 2012 Share Posted May 30, 2012 the irony is that the sealed bulkheads on a multi is to ensure reserve bouyancy if one hull is flooded - that is a multi should still float with one hull flooded. A keel boat on the other hand . . . Link to post Share on other sites
Fogg 427 Posted May 30, 2012 Share Posted May 30, 2012 Monos on the other hand just need explosive quick release keelbolts to stay afloat. Bavaria have pioneered this technology but like many innovators, they remain misunderstood by the masses. Link to post Share on other sites
Megwyn 2 Posted May 30, 2012 Share Posted May 30, 2012 Monos on the other hand just need explosive quick release keelbolts to stay afloat. Bavaria have pioneered this technology but like many innovators, they remain misunderstood by the masses. Don't push the red button. DONT PUSH THE RED BUTTON DONT PUSH THE . . . Didn't I say Don't push the red button? Link to post Share on other sites
DrWatson 375 Posted May 30, 2012 Author Share Posted May 30, 2012 Yeah, quick release keels have been around a while, it's just there is not a lot of control for most yachties as to when they are activated. But you could manage the issue of a sudden holing with enough watertight compartments. If you can seal off the same volume of space as your displacement (4 ton boat = ± 4 m^3) then at least you won't sink on the spot. I'm thinking three watertight bulkheads, one forward of the for'd v-berth, one at the mast bulkhead sealing off the entire forward section, and another sealing off the aft quarters. Of course the trick would be to make sure that you could at least keep her floating somewhat level to make sure your reserve buoyancy was all having some effect. I figure it's more likely to be holed in the forward sections somewhere from ramming into a container or log at sea, so breaking up that space into sealable volumes could have it's advantages. Link to post Share on other sites
Atom Ant 0 Posted May 30, 2012 Share Posted May 30, 2012 If you hit a container or whale hard enough you don't need explosive keel bolts... Link to post Share on other sites
Guest Posted May 30, 2012 Share Posted May 30, 2012 So why not have a set up like a blow up , via gas, bolster running about the topsides that can be set off when needed? If it went from the waterline to the sheer it should be big enough to float the yacht in an emergency. Hard to describe this idea so imagine a long balloon all the way roound the topsides with chambers. Link to post Share on other sites
Grinna 2 Posted May 30, 2012 Share Posted May 30, 2012 Inside or outside the boat Bbay? I'm guessing something like that outside the boat would be more effective but also more prone to UV damage, docking damage, require more maintenance, etc. Link to post Share on other sites
Guest Posted May 30, 2012 Share Posted May 30, 2012 Its just an idea for discussion. If I had it worked out in detail i'd be on my way to the patent office. I guess it would need to be something that is attached before going offshore. It would be best attached outside but conceivable to have a system inboard that inflates say in the engine compartment and the forward cabin. I don't have the maths to work out the details on whether this is feasible but I do think these ideas are worthwhile considering. For alongside a system that uses bubble wrap type bolsters would be most reliable but having somthing flat against the hull that could be blown up instantly using the same system for liferafts may be feasible. Would definitely be a serious investment though. The internal system would probably be cheaper and easier to apply. Link to post Share on other sites
marinheiro 352 Posted May 31, 2012 Share Posted May 31, 2012 i always thought explosive keel bolts were pioneered in NZ, initial trials on the GRP Farr 11.6's were partially successful, and then perfected on many Elliot designs in the 90's. The air bag idea has already been tried, there was a US outfit called Yachtsaver but they were shut down, not sure if was due to faulty design or litigation (or both). If you have access to Dashew's cruising encylopedia the system was discussed there and one set was installed on his daughter's yacht (a Mull Santana 37) which was recently for sale in Auckland Link to post Share on other sites
Guest Posted May 31, 2012 Share Posted May 31, 2012 By email: Absolute cheapest way to achieve this and have spare mattresses for the beach etc, is to have 12 airbeds, the fabric covered on top type which are really tough, and have them packed away in an easy to reach compartment along with a 12 volt mini aircompressor or manual pump. First matress goes into the hole if the hole is big enough and blow it up so it stops the leak but not so much it makes the crack wider. other matresses go into areas expected to flood, keeping note that trim will be affected if one place floods and others don't. Essentially, if the bow gets hit and you can fill up the bow remains with the matresses there will be no area left for the water to settle in, and it should stay afloat, assuming the water that does get in to the rest of the boat is able to be handled by the pumps. A can or two of the expanding foam that sets underwater is great too, but it is best if contained by something, say a pillow case stuffed into the hole first. Link to post Share on other sites
DrWatson 375 Posted June 3, 2012 Author Share Posted June 3, 2012 The mattresses thing is quite an interesting idea. But I think you'd still want to be able to close off the compartment that the hole was in, otherwise, although you'd have no space in that compartment for water to be in, the water would still flood back (let's say the hole is forward of the mast) and flood the after quarters until the trim was affected to the point of lifting the hole clear of the water (best case scenario), or worse, until she sank stern first. Then you have other problems. I'd quite like to be able to have the ability to rapidly seal-off sections of the boat to ensure a balance of buoyancy over the whole vessel. laterally and longitudinally. One advantage, I guess, of a wooden boat is that a plywood patch (or a number of wooden strips can be quickly nailed over a hole if you have to. Nailing through steel, glass or carbon is not so easy... Link to post Share on other sites
Megwyn 2 Posted June 4, 2012 Share Posted June 4, 2012 Remote controlled self sealing emergency bulkheads? Like a sub. Link to post Share on other sites
Bogan 8 Posted June 4, 2012 Share Posted June 4, 2012 Its just an idea for discussion. If I had it worked out in detail i'd be on my way to the patent office. I guess it would need to be something that is attached before going offshore. It would be best attached outside but conceivable to have a system inboard that inflates say in the engine compartment and the forward cabin. I don't have the maths to work out the details on whether this is feasible but I do think these ideas are worthwhile considering. For alongside a system that uses bubble wrap type bolsters would be most reliable but having somthing flat against the hull that could be blown up instantly using the same system for liferafts may be feasible. Would definitely be a serious investment though. The internal system would probably be cheaper and easier to apply. A trip to the patent office would show you that the idea isn't new.... it's been addressed in patents plenty of times, just doesn't seem to be something people actually want to buy. Link to post Share on other sites
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