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1Wiley
Joined: 30 Jun 2018 Posts: 42 City/Region: Bay area
State or Province: CA
C-Dory Year: 1986
C-Dory Model: 22 Classic
Vessel Name: Fidelio
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Posted: Wed Aug 01, 2018 5:14 pm Post subject: |
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That was supposed to be
Tomherrick, those are amazing photos..
Have you finished that project ? |
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tomherrick Guest
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Posted: Sat Aug 04, 2018 5:23 am Post subject: |
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Nope. But, there's hope... |
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1Wiley
Joined: 30 Jun 2018 Posts: 42 City/Region: Bay area
State or Province: CA
C-Dory Year: 1986
C-Dory Model: 22 Classic
Vessel Name: Fidelio
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Posted: Sun Aug 05, 2018 12:13 pm Post subject: |
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Please keep posting pictures, you are quite the builder..
Very interesting to us layman. |
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tomherrick Guest
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Posted: Sun Aug 05, 2018 7:50 pm Post subject: |
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Nice of you to say 1Wiley, but I'm a total novice at this. I've had guidance from two naval architects, a marine surveyor, several very experienced folks in boat rebuild/repair, and a small library of books on the subject. Sidelined by several surgeries, death in the family, and waning confidence in my ability, the project went dormant. Just finishing up a total redo of a West Wight Potter 19 my wife purchased I feel like I have the chops to get the C-Dory done. Hope to get it cranked back up in the next few months.
Back to the subject of your post, I'm still interested in the idea of a system to keep the boat afloat when the stuff hits the fan. That inflatable collar seems worth exploring, but I still have questions about how to deal with damage to the collar itself since it's mounted just above the waterline. The system I referenced earlier has a series of individual chambers, but I think there'd need to be some kind of one-way valve on the supply tubes at each chamber to stop backflow once the pressure air tank is empty. Otherwise it might just end up being an expensive bubble machine adding visual interest to the scene while the boat sinks... |
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ssobol
Joined: 27 Oct 2012 Posts: 3388 City/Region: SW Michigan
State or Province: MI
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
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Posted: Sun Aug 05, 2018 10:21 pm Post subject: |
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I would think that a collar at the upper part of the hull, about the rub strip would be better. If you got to the point where you actually needed it, having the boat float awash would probably be more stable. Yeah, it might not be that comfortable, but it depends on whether you want to keep the boat floating at the normal waterline, or just afloat until a rescue.
The question is whether you'd need more flotation for the awash condition vs. the normal waterline or not. |
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tomherrick Guest
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Posted: Sun Aug 05, 2018 11:15 pm Post subject: |
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My thought at the time was to keep the electrical and propulsion systems dry-ish and functional. Might not get on plane but pointed in the right direction under power would be pretty satisfactory after a significant hull breach. |
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ssobol
Joined: 27 Oct 2012 Posts: 3388 City/Region: SW Michigan
State or Province: MI
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
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Posted: Mon Aug 06, 2018 3:43 am Post subject: |
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I guess it depends on what your requirements for self rescue are and what "significant" means. However, if your expected hull breach is from a collision with something in the water, you might want to have the collar stored/installed on the hull someplace less likely to be part of the collateral damage.
Maybe you don't need a collar, just 4 bags that are attached to the hull that inflate. Perhaps a couple helicopter floatation bags attached to the hull. These are pretty compact packages before inflation. |
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tomherrick Guest
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Posted: Mon Aug 06, 2018 10:51 am Post subject: |
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Of course, maybe what I really need is to simply go fishing and hope for the best... ) |
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Marco Flamingo
Joined: 09 Jul 2015 Posts: 1155 City/Region: Seattle
State or Province: WA
C-Dory Year: 2004
C-Dory Model: 16 Cruiser
Vessel Name: Limpet
Photos: Limpet
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Posted: Mon Aug 06, 2018 11:39 am Post subject: |
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Flotation calcs are always interesting. Getting something to float at a certain attitude is even more fascinating. How much is generous flotation worth if it causes or allows the boat to turn turtle? And, now that we're thinking of the unthinkable, why is it that blues and greens are the popular bottom paint colors? Wouldn't day-glow orange be the color you would want if your boat was floating upside down? Maybe even orange reflective bottom paint? (Patent #1). And since boats commonly turn turtle, wouldn't an automatic pop-up safety grab bar on the bottom be a good idea? (Patent #2).
But, back to flotation. I did a lot of kayaking with storage float bags. Two weeks worth of food, clothing, etc., in waterproof stuff sacks fitted to the shape of each compartment. I still think of that in my little Limpet. Bedding, clothing, etc. are stored in dry bags and fastened down. There is some inconvenience in opening a dry bag to get the coffee out, and some inconvenience in putting things back into a dry bag and connecting to the hull. A flotation bag that floats away isn't worth much. And, again based on kayaking, the power of surging water will quickly scour the inside of the hull of anything not fastened down.
The hull flotation collar looks good, but (based on past research about saxophones, of all things) that concept has been the subject of various patents for over 60 years (because of torpedo sinkings in WWII). It provides some comfort in pictures and on paper. Not so practical in real life.
It seems to me that the biggest difficulty is how to compensate for the weight of the outboard. Every picture I've seen of a floundering pleasure boat shows the bow remaining above the surface, probably because of trapped air which might soon be gone. Knowing that the outboard will become the unintended anchor, why not have full compensation at that point? Something like an inflatable collar on the outboard leg. Right where it is needed most and out of the way behind a cosmetic cover (like airbags in a car). It would deploy automatically upon complete submersion (Patent #3).
There may be such a product already, and the fact that the Flamingo OMFD (Outboard Motor Flotation Device) isn't known to every boater generally might mean that it doesn't work. But maybe it would. And maybe even a design that kept the outboard operational despite partial submersion of the hull (Patent #4).
Marco Flamingo |
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ssobol
Joined: 27 Oct 2012 Posts: 3388 City/Region: SW Michigan
State or Province: MI
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
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Posted: Mon Aug 06, 2018 2:30 pm Post subject: |
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You could have a permanent rail on the bottom of the boat. In addition to providing a handhold if the boat capsizes, it could also double as a keel and motor guard like the full keel does on some trawler boats when the boat is operating normally.
Perhaps there should be some way to quickly jettison the O/B motor in the event of an incident like is being discussed. This would rebalance the boat a bit by getting rid of a large weight at the stern. If the choice is losing the whole boat or just the motor, I don't think it would be that hard a decision to make. |
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thataway
Joined: 02 Nov 2003 Posts: 20866 City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
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Posted: Mon Aug 06, 2018 2:52 pm Post subject: |
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I think that having propulsion system intact, and electronics/ electrical dry is fantasy thinking considering all scenarios involving swamping or sinking.
As far as a catastrophic event--fire is probably more likely. Most sinking I have seen have been due to thru hull failures (including shaft logs). The C Dory does not have any thru hulls (with some rare exceptions). The next most common cause is running onto rocks or reefs--and that is 100% operator error. Swamping due to anchoring improperly (or the very rare wave over the stern or side--) may be recoverable. Hitting an object and sinking is way down the list--about as probably as a whale hitting the boat and sinking it. (I am aware of several boat which were pushed around by whales, and not sunk--and several which were sunk after damage....)
Oh yea of little faith!!! _________________ Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL |
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