Boat Lift for CP-16?

[tmw]

I am fortunate to have access to a boat lift, which is pictured here (and it really is straight, please don't mind the fisheye effect where I tried to get it all in one frame):


I am tempted to modify this in order to accommodate my CP-16.  It seems like that would involve adding a few places to support the hull above the keel, or something like that.  I'm not sure how quickly I'll get to this, but hoping for some thoughts on guidance in case this idea gets momentum.

When supporting the boat, is there a weight bearing philosophy to keep in mind?  For example, is it okay for most of the weight to be supported by the keel, while the side runners are there mainly to keep the boat from tipping over?  Or, should most of the weight be supported by the side runner thing-a-ma-goobers while the keel sits barely touching anything?  Or is it a 50-50 mix?

Also, I'm guessing that the little side runner do-ma-hickey's should also be curved to follow the hull form, or something to that effect (similar to the trailer the boat sits on).  Is that accurate?  Is there an optimal design for supporting a CP-16 out of water?

Last question (for now):  Would my boat be happier sitting out of the water on a lift like this, or sitting in the Brackish Chesapeake Bay Water? (no insult intended to Brackish)   I've imagined that being dry typically makes boats happy, right?  Kind of like how sitting in the garage helps it winter over better.  The other option is to tie the boat up on the other side of the pier in the water.

That does make me think:  if the boat is tied up on the far side of the pier and the water level gets really low (happens sometimes on a cold northerly wind), we have not the deepest water with a muddy bottom.  Would it be concerning to have the boat weight largely supported by the keel in mud and water not adequately deep enough to float the boat?

Okay, probably enough for now.  Not sure when or if I will get to this, but still thought it might be a good learning opportunity just in case the Admiral deems it a great idea.  My current winter priority is to foil the flat plate rudder, since that can be done indoors.

Thank you in advance,
Tim (or tmw since there so many Tim's here?!?)

[JTMeissner]

Tim, that's quite the nice-to-have problem there.  IMHO, I'd go with modifying the lift for the CP-16.  Take into account that the lift can hold the weight (safe side for 1500 lbs of boat and equipment, people?), and I think you're set.  Probably lots of opinions for setting it up, here's my 2 cents: make it look a lot like your trailer, with most of the weight (if not all) carried by the rollers/center beam and the side guides ensure alignment and prevent tipping.  Replace the center board with a nice fat piece of wood for the keel (2x8? and perhaps some Dri-Dek to ensure air gets to the whole thing) and make the two "side runner do-ma-hickey's" match the ones on the outside of your trailer.  Three pieces of wood and some hardware.  The key is the center beam under the keel, so if just that and appropriate lines to the pier mooring to prevent tipping/movement/slippage, that may be all you need.

Can you support the boat via the side guides? I think the answer is yes, and the foam under the cabin berths helps with preventing hull deformation.  I think somewhere I read about using a forklift to move CP-16s, so this is a design factor, but I'm not sure I'd go that route unless no other options were available.  When I re-did my trailer bunks, I just used treated 2x4s adjusted with the flat side to the hull and the weight of the boat nicely formed the proper shape before I tightened all the fasteners.

For longer storage, I think high and dry is preferable, though with the right bottom coating being in the water would be fine.  No issue with osmosis and blistering if out of the water.  If you did have it on the other side, I don't think sitting on the mud would hurt it.  Plenty of boats in the UK use tidal flats for mooring and sit on the ground/mud in between tides.  You just have to watch tipping (that's why some boats have double keels).


-Justin

[tmw]

That's amazing those boats just sitting in the mud like that.  Definitely makes me feel a lot more comfortable about my potential low water situation.  I also like the idea of using dri-dek as a cushion.

Thank you.

[Bob23]

JT:
   Is that England? I think the tide is the reason that bilge keels are popular. I think that's what they're called...maybe just double keels. I hear they have great sailing characteristics that don't seem so obvious to us single keel folks.

[JTMeissner]

Bob, photos were purely from a search of "UK mooring field" since I'd knew it would show what I was looking for, so yes, in the UK somewhere.  9 feet of tidal changes makes this a design factor..  I actually was shopping for a twin keeled boat when I ended up with my CP-16, both in the New England area when I was shopping.  Twin, double, or bilge, not sure there's much difference in name, but I think bilge keels do not technically exclude a central fin, just more roll prevention. Good discussion here of advantages/disadvantages: http://www.duckworksmagazine.com/08/columns/nichols/index1.htm.

And Tim, to stay on topic, that link would show some options for a single keel in a similar tide situation on how to ensure the boat doesn't tip like the one in the background of the second photo.

-Justin