I am looking at a Catalina 36 as a step up from our Hunter 31. While it draws 4'5" our mean low low water is 4' so it will occasionally sit on its keel (as does our Hunter from time to time). At times, it may heel over a bit depending on wind, current, load, etc. although we are in a protected cove. What are the opinions about the impact on the structural integrity if setting on the keel were to happen regularly? If it were to heel a bit? Are unreasonable forces being put on the structural system that would be problematic? We have had no problems with the Hunter, but with the extra 5-6" it would happen more often so I am concerned about impact of this. Appreciate the input.
Catalina keel and structural impact of sitting on the bottom
- Thread starter smontgom
- Start date
Just curious, but when there's a north wind that blows water out of the bay, causing abnormally low water for a day or two by counteracting the tide, how does that affect your boat where you have it tied up?
A strong north wind, or one that lasts for over a day, or just the tide cycles will push water out of the creek and sometimes past my MLLW. That's when the H31 will sit on its keel. January is normally our month we experience this most often, but not this year. If it happens say 12x/yr, am I putting undue stress on the boat, the keel/boat connection or otherwise hurting the boat? It sits on the keel when on the hard so I am less concerned about the straight up and down grounding then I am if it were to heel due to a wind, off centered load, or uneven bottom.
It doesn't care - it's designed to hold its entire weight on the keel. Here's a Catalina 36 calmly sitting on her fin keel. Four pads on the sides just hold it upright, and have no real upward weight bearing. Thousands of C36's, and a variety of other keel boats, pass months of winter in the north this way (with a snow cover on, of course), and it does not hurt them at all. I know it may look odd with nine tons pressing on a 6 x 20 inch spot, but that's how it is meant to be. If you're not fully grounded, a bunch of the weight is taken by flotation, and the healing when aground is natural. These things are stronger than you know.
Hello,
I'm not SO concerned about the keel. But what about the rudder?
If the boat is just sitting on the keel and in the mud then that's not too bad. But if it is bouncing around and the keel if being driven into the mud and the rudder is getting bounced up and down then that is pretty bad.
Barry
I'm not SO concerned about the keel. But what about the rudder?
If the boat is just sitting on the keel and in the mud then that's not too bad. But if it is bouncing around and the keel if being driven into the mud and the rudder is getting bounced up and down then that is pretty bad.
Barry
I get it with the straight up and down...if that were the only issue I wouldn't be concerned. The bed is soft mud....Chesapeake Bay muck. I am focused on if it heels over am I stressing the keel boat joint in a manner it shouldn't be stressed. One can rationalize that when heeled while sailing similar stresses exist. The entire structure or hull is never out of the water all the way so there is some support from the water on the hull. My focus is on the keel boat joint primarily; assuming its properly tightened, etc. where is the problem(s).
The Hunter rudder has never grounded....that was my huge concern the first time I saw the present boat like this but hasn't ever touched the bottom. The depth falls off steadily behind the keel and the rudder does not extend all the way down to the lowest level of the keel. This is a Mk II I looked at; I need to go back and recheck the rudder depth vs. the keel depth. This Mk II has the winged keel with 4'5" draft. The profile on Sailboatdata.com is not clear on this.
And given our protected location I am not at risk for it bouncing up and down repeatedly hitting the bottom. That's a deal killer for sure
Yes, the keel and keel stub are designed to carry the entire weight of the boat. When sitting calmly on the hard. They are NOT designed to carry the additional impact loading of bouncing off the marina bottom when the tide is just right (or in this case, just wrong). The harder the bottom and the greater the drop, the greater the impact force up to and including MANY times the weight of the boat.
DON"T DO IT ! ! ! !
Given the opportunity to move up to a Cat 36, I would do whatever it takes to get into a deeper marina where this problem will not exist with the deeper keel.
Rudder? -- oops, I forgot about that. The C36 rudders are long, and mine comes somewhere within a foot or so of the bottom of my fin-keel. Don't know if they shortened them on the shoal-keel boats, but considering how adverse any mass-production boat company is for maintaining multiple versions of parts, I'll bet not. I doubt that the rudder is longer than the keel in any case, but if not different, it will be 18 inches closer to the bottom than mine.
Call down to the Catalina factory in Fl. They should know the answer. I think you'll be amazed at how helpful they are down there concerning older boats of theirs. The customer support alone will make you feel good about getting a Catalina. That's been my experience.
I'm in agreement with the arguments regarding potential lateral stresses on keel bolts when heeled over and striking bottom (even if MOST of it is soft mud in the Chesapeake there's also debris in the water which might not be kind). The concerns about rudder strike are an even greater issue in my mind. Particularly if a power boater blows thru with a wake at low water. But I'll throw out one more here - if you're heeled over with a grounded keel due to low water, you also risk putting through hulls underwater that are normally above water. Probably not during the normal tidal range, but probably so when the wind blows from the north here. Do you close the sea cocks on all your above waterline thru hulls religiously? That can sink a boat.
Not sure why you keep the boat you have in such shallow water, but agree with everyone else that you may want to strongly consider mooring/docking elsewhere that is safer for your boat - certainly the Catalina with the deeper keel. Am guessing your insurance might also have an issue if they investigated a loss and found the boat was habitually moored/docked in water not deep enough to sufficiently float it. Alternately, ever considered a bilge keeler?
Not a criticism, just an observation.
Not sure why you keep the boat you have in such shallow water, but agree with everyone else that you may want to strongly consider mooring/docking elsewhere that is safer for your boat - certainly the Catalina with the deeper keel. Am guessing your insurance might also have an issue if they investigated a loss and found the boat was habitually moored/docked in water not deep enough to sufficiently float it. Alternately, ever considered a bilge keeler?
Not a criticism, just an observation.
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Could solve your problem the European way. Get a boat with bilge keels. Not sure if Catalina builds one but I know Hunter (among others) does.
I would say no one here has sailed much in Normandy.... There they have like 15 meter tides. Boats there lie on the bottom at low tide all the time. For sure bilge keels are quite popular there, but I'm seen hundreds of regular keel boats lying on their sides at low tide - no water to be even seen.
Mud bottom on the Chesapeake where you are keeping your boat, I wouldn't worry about it at all.
dj
Mud bottom on the Chesapeake where you are keeping your boat, I wouldn't worry about it at all.
dj
We may be overthinking this but laying static in a bed of mud isn't the same as the OP's description of the keel continuously hitting the bottom at an angle.
The keel will compress the soft mud and make itself a hole. It sounds like you are talking about 3”-6” of slurry ... if so there will be no pounding. You do need to be aware of intakes ingesting muddy water.