Bottoming out, damage question

[opie]

Regarding the Mac hitting the bottom, I have a question. What if there are sharp rocks on the bottom when the boat drifts or drags anchor into the rocks? Then the boat repeatedly bottoms out and bounces the hull on those rocks, could a hole be made in the fiberglass? (How thick and strong is the glass under there? Possible to break a hole in it?) And if the hole was made, would the water just go into the water ballast tank, harmlessly? Or is there a way for the water to enter the boat and flood it? And if a hole was made in the ballast tank, how would you know, without taking the boat out of the water?

Just thinking about stuff and worrying that a anchor drag or changing tide could put any of us in that situation. [Of course, I know that landing on the rocks in a surf would mean certain damage. I am talking about intra-coast or lake locations.]

[Kelly Hanson East]

You really dont want any boat hitting rocks, imho. Even small rocks can hole any FG boat, with a sharp enough point, if you will.

[Morimaro]

I ran my X aground on Loch Ree in Ireland, (sand, shingle, stone and rocks bottom) it made a loud scraping sound and stopped the boat (we were sailing at the time). Eventually we were able to motor off and get alongside a pontoon where we inspected the bilges thoroughly for ingress of water but there was none.
Eventually the boat was put on its trailer to reveal some long gouges, that went through the gelcoat and such into the fibreglass base but not through the fibreglass itself. It was relatively simple to clean up the gouges and apply a repair kit to the hull.

The fibreglass hull is relatively resilient but could puncture if you hit a solid object at speed but depending upon where the hole in the hull was, it would either leak into the bilges and/or the ballast tank.

Either way if the boat filled with water the foam floatation would prevent the boat from sinking and you should be able to get back to safety,or if it's a "big" hole, stay on the boat call for and wait for a rescue!

If the hole was into the ballast tank the effect would be that you would not be able to empty the tank normally but the tank being filled by a hole is no different to a tank being filled from the gate valve, so should not effect the stability of the boat assuming the tank bung is in place and the tank doesn't flow out into the bilge. (A good reason to put the bung into an empty tank, when motoring at speed)

Cheers

Morris

[Chinook]

I intentionally anchored at high tide once, near Everglades City, in 3 feet of water, with a tidal range of 4 or 5 feet. It was soft mud bottom and we were in a spot we liked, so I figured why not. The decision was less than satisfactory for a couple of reasons. First, in the middle of the night, when the tide got low enough for the hull to begin touching bottom, the sound and motion of the boat was different enough to abruptly disturb sleep. Second, a pair of racoons with larceny in their hearts decided to take advantage of the opportunity and steal aboard under cover of darkness. They tracked mud all over the place and got me up twice, trying to chase them away. Setting down on the dewatered bottom in that situation didn't harm the hull any, however, for the two reasons mentioned above, I will probably not try it again.

[BK]

Chinook, (sorry to invade this guys post but) I was wondering if you did the Euro canal trip in your Mac? I remember you were looking into it. You did the Alaska Inside Passage and Bahama trips so you probably did this.

[bastonjock]

a lot of it would depend on just how hard you hit the rocks,i parked my boat on a sandy beach that had a few rocks on it,i had no probelms


as for taking a mac through the canal system here be a photo of my mac in a Lock,there are hundreds of locks on the canal system

[Chinook]

The Euro canal trip is still a dream, although an appealing one. Sea of Cortez this past spring was our most recent adventure. We hope to trailer east in spring 2010 for a run out to the Exumas. We'll most likely be in Northwest waters between now and then.

[NiceAft]

Opie,

I would hope that the conclusion you came to is not to do it. It's not worth the aggravation if something does go wrong. The decision could cost you big $$$$. Stay far enough out that your boat is safe.

When I was in college, my statistics professor presented a problem that your question very much resembles.

Lets assume you want to purchase a pack of cigarettes. When you pull your car up to the store, there is a no parking sign. If you park there and run in to make your purchase, will that pack cost you what ever a pack cost, or will it be that plus $25 What is the probability of getting away without a parking ticket? Is it worth the risk? The last question is not statistics The potential damage is far beyond the cost of a pack of cigarettes

You don't want to do a Three Stooges routine. The one where Curly says "Hey, I ressemble that comment Nyuk, Nyuk, Nyuk, Nyuk

Ray

[March]

I am with NiceAft. I typically anchor in a cove where 3/4 of the area around me is soft mud banks and only a small portion is rocky. Dragging anchor doesn't seem like a nightmare--it happened once at night, I was pushed against the shore and could shove away easily in the morning. No harm done. Yet dragging anchor still sounds like a bad idea, and I always secure the boat with two--why take an unneccessary risk?

On the bright side, the Mac is pretty resilient. I beached it a couple of times and hit a couple of rocks (or pebbles) and scratched the bottom--nothing that MarineTex wouldn't fix in 15 minutes. Also bumped into a dock that sported an ugly piece of metal sheet that sctatched the side badly--but didnt go through. But counting on its resilience and testing it is like tempting Fate. Not a good idea. Prefer to stay afloat and away from the rocky shores