[Disclaimer -- the following is written by a catamaran dealer] Dear Randy & Carol, I'm writing in response to your open query regarding a recommendation of a 40-to-50-foot power cat that you could keep moored in front of your home on Vancouver Island -- a beach that you say is exposed for close to a mile when the tide is out. I was born and raised (and currently live) along the shores of Puget Sound, about a day's run (by semi-displacement power cat) south of you. So, I'm familiar with the tide conditions you mention. (Highest tides here in Seattle can run to about 12.5 feet, while the lowest tides are -4' or so -- that is, a nearly 17' maximum tide differential. Your being north of here probably means you have at least that difference, if not slightly more. So, the first question that comes to my mind is: Are you SURE you want to have a cat (or any large yacht) moored in front of your home? Of course, I can understand the pride-aesthetic attraction of having "your baby" moored right out front. But have you thought about how little you'll be able to use it? I'm assuming that, as in Seattle, you have 2 high, and 2 low tide settings per day. Given the height tide you'll need simply for your cat to refloat, I'm wondering if your actual use of the boat might be limited to a few, scant hours per day? Plus, if you don't return at a fairly high tide, you'll probably not be able to reattach to your mooring. Of course, that presupposes that you plan on having said mooring fairly close to the mean, if not high-tide line, in front of your home. If, conversely, you moor it out closer to the low-tide mark, then (by your own description), it sounds as though you'd have an appreciable hike (half-to-full-mile!?), just to get to your boat (since anything but a fairly high tide wouldn't allow you to simply row a dinghy to the "mother ship") So, a $300K to $700K investment for a yacht that you can only use for a a few hours each day seems a somewhat questionable mooring choice. (But, perhaps I'm missing some other favorable aspect about that moorage decision.) Second, a 40 or 50-foot cat isn't some lightweight vessel. So, I'm wondering the actual bottom-conditions on which you plan to have it sit. If the cat is fiberglass, don't forget that really means simply "glass-reinforced plastic." Take a bit of sandpaper to your plastic toothbrush handle and see how many swipes of that sandpaper it takes to mar the finish -- yeah, like one swipe! The point here being: at the four times each day when your cat is semi-floating (either just before it's fully floating thanks to an incoming tide, or almost hard-aground with an outgoing tide), your hulls are going to abrade on the silt beach you've described. That grinding will be the result of the force of passing vessels' wakes, wind ripples, or even just gentle rocking even though the hull has achieved slight contact with the silt beach. That silt will be just like sandpapering the fiberglass surface of those hulls. Worse, I suspect that twice-a-day abrasion to your fiberglass hulls would be unavoidable. In the past, I've assisted clients (who wished to regularly/periodically beach their smaller [20' to 35'] power cats), by having stainless-steel strips (runners) affixed to the bottom of each hull. But those are just first-contact points. As the tide recedes, more than just the slim width of a stainless steel runner under each hull will be subject to the slight (or not so slight) grinding/sanding effect as your boat moves a bit, back-and-forth, back-and-forth, before finally being high-and-dry. And during that "wriggling" back and forth, ALL of the fiberglass surface that grinds back and forth on that silt will suffer some degree of abrasion. In the end, even in fairly firm sand, I'd estimate each hull would be in contact with sand-or-silt for a 4" to 12" wide portion of each hull, running the length of each hull. Of course, if the design incorporated a 4-to-6-inch deep keel (perhaps about 2" wide) along the length of each hull, that would preclude much/most of this concern about abrasion. (This condition exists for the majority of sail-cruising cats, which have twin keels, each about 2-inches wide, and perhaps 15" to 24" deep.) Better yet, you then could specify a strip of kevlar being laid along (and around) the outer surface of each narrow keel, said strip being something you could consider sacrificial. That is, you'd replace (or add another) kevlar strip as necessary (every 2-3 years ...?) during a routine haul-out. Unfortunately, I can't recall ever seeing a power-cat hull that had full-length mini-keel extrusions. But, if you're going to have your cat custom-built, I would think a designer could incorporate that into the hull design. In Europe there's hardly a harbor that doesn't include grounded power boats at every low tide, many of which are specifically fitted/designed with twin bilge keels, for that very purpose/condition of grounding during each low tide. Of course, absent such "legs" (keels), I don't have to describe the effect that twice-a-day grinding will have on the $150-per-gallon bottom paint WHEREVER such painted portions come in contact with the beach. And as SOON as that paint's been scoured from the FG, you'll then begin to grow barnacles like crazy...and they can get BIG up here in the northwest! Of less concern (but not ignorable), is how long you'll wait once the boat has JUST begun to float before actually trying to maneuver her into deeper water. Because when you have just an inch or two of water under the hulls, and then begin to power her, if -- as you've noted -- you have a silt beach, the props' RPMs (especially in extremely shallow-water conditions) are going to be stirring up the silt, so you're most likely going to be pulling that silt into the engine-cooling-water intake. (Emulsified "sandpaper" isn't any less harmful to a boat's cooling system than is the UN-emulsified "sandpaper" to the boat's outer hulls when they're rubbing back and forth on that silt.) Of a more random nature -- can you be sure that each time an outgoing tide leaves your cat on the hard, that an inch or two (or three) under that silt there aren't ANY rocks, barnacle encrusted or not, nor buried timbers (common in northwest bays) with protruding spikes, etc.? Because, as the boat settles into that silt, it's going to settle down INTO the silt. I have tide flats in front of my own home here on Puget Sound. At first appearance they appear to be ever-so-inviting to a boat's hull(s): smooth and seemingly inviting to any grounded vessel. But when venturing out on them with bare feet and a shovel, it's amazing the range of hard, sharp, nasty-stuff one can find just under that thin layer of surface sand/silt. Again, the obvious risk to your hulls becomes not only abrasion, but gouging -- worst case, even puncturing. And yet, at first glance, you might think there's only a smooth, safe, sand/silt surface that your vessel's going to nestle down onto. So, friends -- don't shoot me; I'm just the messenger. However . . . knowing the approximate conditions that your would-be moorage area likely presents, you can see that I'm skeptical about your overall plan to keep your cat right in front of your house. If it could be done without any of the drawbacks I've mentioned, it would be great. But keep in mind that there's a reason that you see almost NO large yachts moored inside of the low-tide mark ANYWHERE here in the Pacific Northwest. A well-built boat can handle all manner of wind-wave-water conditions when it's afloat with plenty of water beneath it. But, when partially or fully grounded, the average yacht is much more vulnerable to gradual -- or quick-term -- damage. (And, again, during the entire time it's not afloat, you can't use it -- plus the nuisance of having to ALWAYS plan on a specific return time in order to access your non-deep-water mooring.) Do share with all of us what your eventual moorage decision is -- and how it works out. Good luck, Rod Gibbons, pres. Cruising Cats USA Seattle - SF Bay - Hawaii (877) WE-R-CATS > ---------------------------------------------------------------------- > >> >> On 2010-08-30, at 10:49 PM, Randy Smallwood wrote: >> >> >>> George: >>> >>> My wife and I are looking for a 40 to 50 foot power cat that can be beached. >>> We have a beautiful oceanfront property in Vancouver, Canada, but typically >>> have 15 foot tides which, at low tide, leave about a mile of silty sand in >>> front of our house. We would like a power cat that we can moor in front of >>> our house, so the drives have to either be legs that we can raise, or >>> ????? >>> >>> Any suggestions???? >>> >>> Randy and Carol >>> >> _______________________________________________ >> Power-Catamaran Mailing List