Sinking Boats

[Brian]

Easy Really, put the boat somewhere hot.

[Oddfellow]

Easy Really, put the boat somewhere hot.

Try Monaco.

[senator]

Tenerife should do it, looking at Brian's photo's anyway.

[NorfolkNog]

Thanks for your thoughts folks, sounds like a warm wetshed would be the ideal but need a very big lottery win. I like the system Andy describes, so if the boat was used fairly regularly it could be re-winterised fairly easily and perhaps the domestic side could be set up in such a manner that draining down the system was as straightforward as possible.

[quo vadis]

Wombat shouldnt that read sea cock, or do you know something I dont

[Antares_9]

Actually it's quite simple Howard, keel cooling, no raw cooling water to worry about then, a provision to easily drain the potable water and a drop of antifreeze down each lavie when you leave.

Though I confess I prefer the idea of parking somewhere warm.

[NorfolkNog]

Must say never thought of a keel cooler David. Are there any drawbacks, e.g. could they overheat in hot weather?

[Antares_9]

Not if they're correctly specified Howard, they are the ideal answer to weedy conditions too, from memory I think a couple of people on here have them on broads cruisers and though I may be wrong I think some hire boats had them too.

[Guest]

You still have the toilet though Mark.

On yours you will have a steel tube running from the transom plate leg intake up above the water line, before changing to a rubber hose to come back down to the raw water pump, so it should be no problem.

Guess what, changing my raw water pump revealed that all the elevation does is creates a syphon and if the hose comes off the pump the water pours in unless you lift it about 3".

I'm glad I read this thread carefully before chipping in.

Senator is exactly right with that point about the 95% of outdrive boats that draw the raw cooling water through the leg.

When I tried to drain my Volvo Penta Petrol V engine via the brass drain plugs on the blocks, it ran for quite a while before I realised it was syphoning.

I then took the hose of the raw water pump inlet, and it was gushing out until I lifted it up above the waterline to break the syphon.

So yes, no seacock available to close (or possible to fit), and if I hadn't drained the engine and the pump housing had cracked or the lower engine block had cracked, she would have started taking on water.

I'm still wondering about the fixed 1" stainless steel inlet pipe from the leg, and the twin large diameter steel exhaust risers from the transom shield. Whilst my boat is afloat, they are full of raw water to within a few inches of the tops. If it got cold enough, and the engine bay heaters failed, could they not freeze and crack open ? Each exhaust riser is about 3" diameter !!

[Guest]

Here's a VP cross section showing their outdrive setups in relation to the waterline.

[diesel falcon]

Re: Sinking Boats

by quo vadis » January 6th, 2011, 4:29 pm

Wombat shouldnt that read sea cock, or do you know something I dont

The Cummins powered lighthouse keeper

quo vadis

Full Member

Posts: 74

Joined: February 13th, 2010, 3:18 pm

I don,t think wombat should really play with fire!! quo,??

[Oddfellow]

Actually it's quite simple Howard, keel cooling, no raw cooling water to worry about then, a provision to easily drain the potable water and a drop of antifreeze down each lavie when you leave.

Though I confess I prefer the idea of parking somewhere warm.

In most cases, you'd still have a raw water fed wet exhaust with a keel cooler fitted.

I have Keel Coolers in Rambling Freedom and Sweet Freedom and Song of Freedom had one at some point in its history - all Aston boats.

[senator]

Good point Strowager,

The consolation I draw there is that as my boat is registered as in commission for 12 months of the year with the insurance, it would be impossible for me to do anything about it so I assume the insurance would pay out.

[Guest]

I think you're quite right there Senator, mine's insured for year round use as well, and as you say, that's the original spec for the majority of VP and Mercrusier sterndrive boats.

Nevertheless, I'm in the process of fitting a Vetus remote strainer in the intake hose between the leg and the raw water pump. (I'm a belt, braces and parachute man )

My logic is that then, when I winterise, I can run the engine for a few seconds whilst pouring a gallon of pre-mixed bio friendly antifreeze into it, then stop the engine.

Then when I screw the lid back on, the syphon will already have been broken, and the entire raw cooling system will have antifreeze in it, including the upstands from the exhaust and the upstand from the intake pipe.

That's the theory, anyway. There's still the slight problem that the exhaust and inlet pipes are open to the outside water at the bottom and can't be closed off, but I'm hoping that the lack of any circulation will keep some concentration of antifreeze in those pipes.

[Guest DAYTONA-BILL]

i know this might sound a bit obvious, but are these pipes lagged, like any water pipes in a loft say, and if not, why can`t you lag them?.

[Guest]

I can see your reasoning Neil, but the pipes in question have a number of unusual factors.

The internal exhaust pipes are very large bore with thick steel walls, about 4 " diameter. They're bolted directly to the inside of the transom shield, which is a very heavy aluminium casting, which is in direct contact with the water outside.

The internal exhaust pipes are therefore in very good thermal conduction contact with the water outside the boat, so insulating their air surface inside the engine bay wouldn't shield them from the cold. In fact, since the engine bay has a thermostatically controlled tube heater, if I insulated the exhaust pipes, it would insulate them away from their only source of heat (the air in the engine bay).

It's the same situation with the heavy stainless steel inlet pipe. That's a smaller diameter, only about 30mm, but it is also bolted directly to the aluminium transom shield, so is in very good thermal contact with it as well.

Here's a clearer colour photo of the engine and outdrive, showing how the (white) pipes are integral to the transom shield, and how large the main casting is.

[Guest DAYTONA-BILL]

Hi Strowager, thanks for the reply, but i was talking about the inlet hoses from a seacock for a shaft drive set up. The "Z drive" set up i thought are self contained are are much more involved.

[Guest]

Hi Strowager, thanks for the reply, but i was talking about the inlet hoses from a seacock for a shaft drive set up. The "Z drive" set up i thought are self contained are are much more involved.

It's recommended to always close all seacocks whenever leaving a boat unattended for any length of time, Winter or Summer, and can make Insurance claims "difficult" if not done.

Hoses don't split through freezing and thawing as they are flexible, unlike thin walled rigid pipes.

My understanding of some boats sinking from the recent extreme freezing conditions is where rigid raw water pipes or castings have split and then been allowed to flood the boat because the protecting seacock had been left open. The most common example being the fairly common tall brass inlet strainers fixed directly to the top of the inlet seacock., like this one. You could lag it, but it's safer to isolate it.

[Antares_9]

You wouldn't even know for sure if that valve were closed though, gate valves really have no place on a boat in my view, especially in a critical situation like a through hull. That whole thing looks a bit Heath Robinson anyway, also a single hose clip; all below waterline joints should have double clips. I'm not too keen on what appears to be soft soldered joints either.

[Guest]

You wouldn't even know for sure if that valve were closed though, gate valves really have no place on a boat in my view, especially in a critical situation like a through hull. That whole thing looks a bit Heath Robinson anyway, also a single hose clip; all below waterline joints should have double clips. I'm not too keen on what appears to be soft soldered joints either.

Believe it or not, it had been "professionally" fitted to one of my previous boats when I first bought it, and had been in use by the previous owner for 10 years.

A good exhibit for a Surveyor's "black museum".

I replaced it immediately with a proper DZR ball valve seacock , reinforced intake hose, and a remote Vetus strainer above the waterline.

[Antares_9]

Believe it or not, it had been "professionally" fitted to one of my previous boats when I first bought it

Oh, I believe it quite readily, the quotation markes are well placed.

[Palmtree]

all below waterline joints should have double clips

It's worth noting the ISO standard for through hull fittings states double clips are required not only below the waterline but also above it for something like 200mm for cruisers and 400mm for sailboats (I will look at the standard tomorrow to check).

Ian

[teadaemon]

It's worth noting the ISO standard for through hull fittings states double clips are required not only below the waterline but also above it for something like 200mm for cruisers and 400mm for sailboats (I will look at the standard tomorrow to check).

Ian

Very true, but also worth noting that for retrofitting double clips are only advisable if there is space to fit them - if the second clip is partially or totally off the end of the solid pipe then it will tend to pull the flexible pipe off the fitting. In that situation whilst it's preferable to replace the through-hull or seacock with one that is long enough to fit two clips, if it's not immediately possible then one clip is better than two.

[Palmtree]

Hi,

Checked the ISO 9093-1 standard for seacocks, when fully loaded it states two clips on hull fittings 150mm for motorboats and 300mm for sailboats above the waterline. As Teadaemon has said it is very important for the clamping length to be long enough to take two clamps and this is also specified in the ISO standard.

Ian

[Antares_9]

Indeed, no point in putting a clip on if there’s nothing to bite the hose to, as Teademon says it only serves to pull the hose off. Also don’t think they should be over tight, do you specify specific torques for your Lloyds approved clips Ian?