Cat - Rising water failure modes

[redneckrob]

Originally Posted by Barra

Well there are 2 kinds of sailors out there - ones that have had serious green water over their bows and the ones that havnt.

The former would not consider the kind of design you are talking about if they have plans to take their boat where it might see those kinds of conditions. Full stop.

Remember these designers you are putting all your faith in won't be there with you.

If your just planning on island hopping then don't sweat it or the rising water issue. All of them are capable of dealing with short term water ingress even if you are down an engine.

So I'm your sailor type 1, green water over the bows in the Gulf of Alaska and the central Pacific. And while I wouldn't look forward to seeing that in my production FP Mahe 36 or any other boat, I don't have any concerns that it could survive it. My boat is definitely designed with these things in mind, there are voids filled with foam that are clearly there as the direct result of calculations around buoyancy when holed. The idea that a boat designer would have to be in the boat with you to do a good job is just absurd, pretty sure the SR-71 designers never flew in it nor did any Apollo designers make it to the moon....by your logic that means they did a bad job and can't be trusted.

BTW, which type of sailor are you?

[MikeFergie]

I’m not sure why you say they will not do well. Both front hulls have sealed waterproof compartments and the engines sit in rear compartments that can be holed IE rip off the sail drive and they will still float.

Don’t believe me look up “effing Marvin” on you tube where a leopard 44 went right over a metal fish trap off the coast of Spain. Ripped off both rudders. Holed both rear engine compartments and the boat was towed in the next day and lifted out the water and sailed back across the Atlantic following repairs

[Mr B]

I had a hole in both hulls, It was sitting on rocks on the beach,

I had a foot of water in both hulls, That was just enough to cover the battery bank as they were sitting just above the bottom of the hulls,

First off,
The sparks and flames shooting out as the batterys got covered scared the hell out of me as I thought they would explode and I would have a fire to deal with as well as sinking,
But no, They just went totally dead, Shorted out, Much to my relief,

No power, Means no diesel engine either, You cant start it with no batterys,

Second,
With no power, All my pumps were dead, A manual pump just dont make it,

With my repairs to my boat, My batterys have been relocated up high,
Same level as the cockpit floor and motor,
So I will now have power till the water is at deck level, Allowing me time to blow up my tractor tubes to keep it afloat,

200 amphr Battery weight is the same as one person, 73 Kgs, And being on almost the centre line of the boat now makes it a better seaworthy aspect than being almost on the out side of the hulls and under the waterline as previously situated,

Sinking a boat gives you a whole new perspective to look at in keeping your boat afloat if you do get a hole in your hulls,

Sitting on the beach didnt allow enough water depth to try out my four flotation chambers to see if it would actually sink in deep water,

Cheers, Brian,

[conchaway]

Having been castigated previously for disparaging catamarans to upright after being knocked down, I would never, ever do so again.
However, I would strongly advise you to revisit your high school physics and decide for yourself the wonders of "cats".

[Barra]

Originally Posted by redneckrob

So I'm your sailor type 1, green water over the bows in the Gulf of Alaska and the central Pacific. And while I wouldn't look forward to seeing that in my production FP Mahe 36 or any other boat, I don't have any concerns that it could survive it. My boat is definitely designed with these things in mind, there are voids filled with foam that are clearly there as the direct result of calculations around buoyancy when holed. The idea that a boat designer would have to be in the boat with you to do a good job is just absurd, pretty sure the SR-71 designers never flew in it nor did any Apollo designers make it to the moon....by your logic that means they did a bad job and can't be trusted.

BTW, which type of sailor are you?

You misunderstand me.

I'm talking about the large front cockpit designs being dangerous when you are taking waves over the bows. The Fps and most lagoons and older lepoards are all much safer in these conditions.

Yeah I've had the bows submerged in the southern ocean. I know how quickly it can happen and how much force and weight is suddenly applied. It can be catastrophic to other designs too but I'm not going to add to that risk by my choice of boat.

[Barra]

Originally Posted by MikeFergie

Why is it that people that have never even sailed on a boat have the most to say [emoji848]

Take a look at this Leopard 44 delivery in the southern ocean (with its bath up front)
https://youtu.be/hQ-svmgOxqw

Few monos or other boats would cope so well ...
Nuff said they are good blue water boats

No this is an older design leopard 39. No front cockpit.

Much safer design.

And it's sailing downwind anyway. Safe as.

[Paul Howard]

Most production cats are foam cored and even when flooded only settle some inches into the water.
A friend ran his 44ft. custom build foam cored cat onto a reef and poked the saildrive up through the hull and holed the one hull forward of the fixed keel. Water flooded the one hull, the other hull was not damaged. The flooded hull settled about 18" below the usual waterline, but not more. He was able to get the boat off the reef in that state and beached it in an anchorage to make temporary repairs.
Now, many years later after the repairs, the boat is still sailing long passages.

[Montanan]

A valve-regulated lead-acid battery (VRLA battery) a.k.a. sealed lead-acid (SLA) or maintenance free battery should not become damaged in short order if it becomes submerged in water as the valve opens only when internal pressure exceeds the valve's design release point. Water should not intrude into a VRLA battery unless it is sinks deep and the water pressure somehow implodes the battery.

It is the unsealed items that are connected to the batteries that will rapidly not react well to water intrusion, e.g., most inverters and non-water proofed electronics.
Water submersible electronics can handle getting wet up to a certain depth beyond which the weight of water invokes pressures that will cause water to entrain and can short things out.

I have seen engine starters work while submerged underwater and as long as the water doesn't enter the engine block or into the air intake or into the engine electronic controls, many engines will continue to operate underwater. Obviously not an optimal condition for such machines. Diesel engines don't have spark plugs, ignition wires and distributors, and coils so they don't have such components that will quickly short out if they get salt water into or on them.

High voltage can become hazardous when water enters the mix, but 12 to 24 volts generally is not an major issue. Salt water conducts electricity but with a degree of resistance so current will flow and certainly draw down the batteries and can provide an alternate circuit pathway reducing the flow of current to operate important things like bilge pumps. Clean fresh water is not highly conductive.

Worse thing that can occur is the boat sinks.

[Mr B]

Hook up 3 8D's in parrellal in a tank,

Fill the tank till the terminals are covered and come back and tell me your batterys are still working, Hahahahahahaha

[Rustytony]

Um, Er, a few misunderstandings in here I think.

First off... yeah Leopard cats get boat delivered, but also delivery captained. Saying they are not seaworthy is not a fact... it’s an opinion... but opinions vary.

Second off... 14 inches below the water DOES look like a fire hose when it pours in through a sufficiently large opening. But even a trickle can give you giant problems if it’s happening while you are not there or are asleep.

Third off... yes watertight bulkheads are the best defence... but this thread is asking (and not receiving as yet) opinions on whether there are any differentiation in this ’water ingress’ regard between the big prod companies. Eg do they all spray foam into bulkhead cable access holes?

Lastly, worrying about battery position is not a “nill” concern... if you are looking at this aspect of the boats then it certainly is something to consider. Your large bilge pumps, for instance, will no longer work if the level reaches your batteries terminals.

I was not looking for a “forward bathtub” debate. Or a “prod cats are not seaworthy” debate... the forum is full of them.

The one thing I wanted to know was if anyone had views about the actual pros and cons for handling a “taking on water” situation. Thanks for any advice.

[Mr B]

My four sealed bulk heads are completely empty,
You can take the caps off them and look inside for water ingress, or just an inspection,

The two sealed rear tanks are 1.5 cubic metres, so will keep 1.5 tons above the water line,

Dont know the size of the forward tanks, But I assume they will be close to the size of the rear tanks,
The rear lockers are 1.1 cubic metres, inclusive, which will keep another tonne above the waterline,
So 1,5 X 2 plus, 1.1 rear lockers, = 4 tons, My boat weighs approx 5 tons loaded,
So I will sink, Unless I add some extra bouyancy to it, A couple of large tractor tubes will do that,
As long as I have power to inflate them, They fold flat and take up no room in storage,
This has been a good exercise to know what I need to know and keep my boat afloat,

[Rustytony]

Originally Posted by Mr B

My four sealed bulk heads are completely empty,
You can take the caps off them and look inside for water ingress, or just an inspection,

The two sealed rear tanks are 1.5 cubic metres, so will keep 1.5 tons above the water line,

Dont know the size of the forward tanks, But I assume they will be close to the size of the rear tanks,
The rear lockers are 1.1 cubic metres, inclusive, which will keep another tonne above the waterline,
So 1,5 X 2 plus, 1.1 rear lockers, = 4 tons, My boat weighs approx 5 tons loaded,
So I will sink, Unless I add some extra bouyancy to it, A couple of large tractor tubes will do that,
As long as I have power to inflate them, They fold flat and take up no room in storage,
This has been a good exercise to know what I need to know and keep my boat afloat,

Yes I agree it’s worth considering this sort of thing and if possible doing what can be done to improve survivability in the worst case happening. Thanks for sharing.

[mikedefieslife]

Having been on a few modern boats (not just cats) what strikes me is all the moulded furniture items, especially in the heads. Should the hull be pieced or leak behind these, the only way to get to it would be with an axe.

[Mr B]

On my Cat, I have two hulls, One inner and one outer hull, They are about 5 inches apart, Maximum in the deepest part,

I dont know about other Cats and how you get to find holes in them,

I have two holes in the false flooring to get at the hull under the false floor, The Bilge, ,
If I get a hole any where in my boat,
Finding the hole would be impossible,
Repairing the hole from inside the boat, Impossible,
The water does flow from full forwards to almost the transom,
Stemming the flow from inside the boat, Impossible, Unless its a thru Hull, I have access to all of them,

Being woken up at night in a raging storm with over a foot of water already in the boat,
The water is full of sharp things that have floated out of the flooded cupboards,
Dont get your feet stabbed by sharp things,
Your shoes are gone, In the water some where,
I was on the Anchor, Moored, You dont have to be at sea to get a hole or two in your hulls,

First off, Suppress the Bloody Panic, You havent drowned yet,

Second, Get a light happening so you can assess the situation, You cant see in the dark,
And feeling around with your hands, is not good enough,
Third, Find out where you are outside,
Are you sinking, Will you sink,
Are you in deep water, on the rocks, on the beach, ????????????????
Do you need to get the dinghy off the davits, Before you sink,
Are you safe on board or immediate escape off the boat into the dinghy or onto the land required,
Is your crew safe and unharmed,
What other eminent and immediate danger are you in,

If your relatively safe,

Now, you can start your pumps and save your self,

Knowing you cant and wont sink relieves most of the stress in a very bad situation, ,

,

[Wmkenney]

Good question that I never really considered, but as an owner of a Leopard 44, the engine bays are not connected to the main Hull meaning if there is water in it, I don't believe it will reach the main Hull, and it has it's own auto bilge 1100 gph. The main hulls have an auto 2000 gph with 2 float switches as well as a manual hand bilge, and I have additional 4000 gph (12volt) back ups that can be put anywhere on either Hull at any time. In addition, we have wooden dowel kits tapered off all sizes, and foam cones to plug some accident puncture. If there was a Hull fracture this may not be enough, but engine bay wise would likely never happen, main Hull I have electricly 10,000 gph electric capacity in addition to hand pump bilge. This could buy time hopefully. This can be done on any cruising cat, and should be. I disagree with her sea worthiness, she has been all around the world, from Africa to the Pacific, Carrabean, and now US. She has put her bows underwater with me at the helm, and she has been sailed by many. This forward balcony has not been an issue in the industry YET, I'd say you'll love the L45. The forward balcony is priceless!