Submerged mooring a Laser

K

Keith Sharp

New Member
10 year wait for official moorings here around Sliema and St Julians in Malta, dry moorings seemingly unavailable, no car, house 300 steep one-way street metres from sea with Laser currently hanging from rafters. Solution seems to be to store Laser hull by sinking it maybe 3 metres deep and taking the chancc on theft. Weight will probably be limestone rocks in a net, secured through daggerboard slot. Question - necessary weight of rocks? I'm guessing that a Laser has a submerged displacement of around 400 kg, so would need around 600 kg of limestone with density around 3. Anyone got better estimates please? Anyone tried this? On bottom the boat/rock combo would need negative buoyancy of maybe 10 kg, so could be dragged to surface by line after being snagged from shore. While sailing, weight would be left hanging from jetty near surface. Number of fingers lost while switching weight has yet to be estimated.
 
FWIW, just my opinion, see what others think -
I have several major concerns- the boat filling with water, and/or ruining it by the constant water pressure and/or tension of the holddown line thru the daggerboard slot.

Considerations-
- All Lasers have a vent hole drilled in the forward wall of the footwell, underneath where the hiking strap attaches. In addition to that vent hole, I'd venture to guess that there are not many Lasers that are 100% watertight - that is, the deck/hull joint seam around the boat; and that not many Lasers are strong enough to REMAIN watertight after constant and extended strain and pressure as in this description.

- Even at only 3 metres down, water is already exerting 29 KPa = 4.3 pounds per square inch = 620 pounds per square foot -- crushing the boat with a WHOLE LOT of force.
The boat is filled with air, which is very much compressible, so the boat will yield and bend under this pressure. I'd think that if it didn't simply crush the boat, it would pretty quickly compromise that seam, soften and/or collapse decks and/or hull sections ... who knows, but conceptually it does not seem good.
Submarines and pressurized aircraft fuselages are built in a cylinder shape with rounded ends (or in spheres) specifically to withstand great pressure, altho it's also a somewhat streamlined shape too.

- I don't imagine the daggerboard trunk/slot is engineered to carry that kind of vertical load.

- as a more manageable issue, I'd guess the boat will not likely "float" level - you'd probably have to secure it by a 2nd point forward or aft, to keep one end or the other from floating up.

That's just one guy's first reaction. I hope you find a good solution.
I'll bet the sailing is beautiful there. It would be a rotten shame to not find a way to enjoy it.

P.S. - do you know anybody with waterfront property or access, who might let you keep it upside down near the water's edge, in exchange for a lil cash, vino rosso, or other? Or could you invest some of that 10-year wait, trying to cultivate said relationship?? just a thought ...
 
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cskudder. thanks for your response. Indeed I had not thought about 620 pounds per square foot even at only 3 metres depth, but of course you are right. Won't water infiltrate the foam at that pressure and save the seams?

Wait ten years for a mooring ? Well let's just say that yesterday was my first time sailing a Laser since 1975, and it was ...bitchin'
 
Keith- I'll bet it was great to be back out sailing after all that time, and I'll bet it's gorgeous around there- seemingly near idyllic place for a Laser.

I believe the foam is closed-cell, and is sandwiched between impermeable fibreglass - until/unless it cracks. But, whether infiltration - implosion - who know how things would start going badly at first, but seems likely they'd end badly. Simply trying to envision 600 pounds per square foot of surface, having a hard time imagining the entire hull having the structural strength to resist that, thinking it'd simply collapse / implode somewhere that's flatter. But - who knows how, and the end result still looks likely "not sailing," regardless of how it starts.

Hope you find a solution that gets you out on the water when you want - spare patch of dirt, someplace with a rack, a path to the water ... ???
Best of luck with it.
 
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<<who knows and the end result is not sailing.>> Right, but it's the same end result if I leave the Laser hanging from the living room rafters where it is now. OK, maybe I'll sink the hull in 2 metes = 6 feet of water. My gut feeling is that a Laser hull can survive that depth.
 
More info and rethinking after above comment: 148255 UK-made Radial. No inspection port. A buoyancy Cubitainer (?) vaguely visible in photos through transom hole. It’s easy to believe that there are the apparently standard three 10-litre bags forward and three 20-litre bags aft. Current plan is to drill a big (maybe 2 inch) drain hole in transom and sink Laser hull for storage. Presumably, given the buoyancy bag information, 100 kg of limestone, specific gravity about 2.8, should sink the hull, maybe held in net secured through daggerboard slot. And presumably the Cubitainers will squash somewhat at depth three metres. Do people think this might work? Do you want to see a selfie of me sitting on the sinking hull winching it down towards the rock on the seabed? :)
 
Keith... I have visited your country, and I know how crowded it is, but seriously... this story is simply three weeks late.
 
Keith, I notice you've posted even some pictures on another forum (and gotten some reasonable suggestions, too), so I guess this is for real, after all...

Now what I would do (if I were you) is to simply contact your national sailing authority (http://www.sailing.org/about/members/mnas/malta.php) and/or your national Laser class contact: (http://www.laserinternational.org/contact/europe)

...and tell them, "Hi, I'm a Laser master from St. Julian's, where can I keep my boat/sail from? I've already considered some extreme options."
 
[quote=" Solution seems to be to store Laser hull by sinking it maybe 3 metres deep and taking the chancc on theft..[/quote]

Brilliant solution. However, you will need more than 3 metres of water if you keep the rig and sail up. The biggest concern of all would be what color bottom paint do you apply to the entire boat? You could end up with an Olympic level of growth on your Laser.
 
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