Through hulls on passagemakers ???

Stating that xxxx vessel is "Designed in accordance with Lloyd's Rules" is practically meaningless. It does not state which rule or section of rules, we assume structural but the electrical (to pick only one item) system is not designed to Lloyd's, nor the firefighting, or bilge pumping, or anchor gear....etc.

Unless the plans have been submitted to Lloyd's, vetted by their NA's, and corrections made and re-submitted, the design is not to Lloyd's standards. If it is each drawing will exhibit a Lloyd's stamp. And unless all materials, equipment, welds, welders, shop, etc. are Lloyd's approved, and the vessel is built under survey by Lloyd's, it is not built to Lloyd's Rules.

There is a good reason to submit drawings to Lloyd's; to have the designer's mistakes and oversights corrected by qualified peers. At the very least you get alternative ideas on how to solve some complex problems. It's a learning experience for both parties. Knowing the sometimes numerous oversights in many designer's drawings I would highly recommend it. But it costs money, people will spend thousands on chrome and plastic foolishness but buy only the cheapest design available.

 

Where's the adventure in that? My idea is that it might be cheaper buy a boat on the Med, for a summer, and sell it when done. That would be an adventure of a different sort! Lot's of ways to skin that cat. First for us is US waters and the Gulf. Then, we will see! I hope our home closes on time!!! robert

 

So far the proposals for thru hulls all seem too complex. I run 1000 engine hours, one thousand generator hours per season and simply never have plugged sea strainer problems.

When installing new plumbing keep the system simple, easy to service and by all means consult a naval architect or marine engineer for pipework specification and layout . Hard plumbing...metal or PP is more reliable, more compact .

You will save much time and produce a superior product.

Georg Fischer supplies many of the fittings and pipework we use.

http://www.piping.georgfischer.com/go/54F3AAB4D60EB5F06F18D45D0AA77F21

 

One's is enough when it happens in the wrong place, thou you have been lucky considering your scrubbers are allways clogged with debri

Hmm.. that sounded much worse than I meant

 

the amount of scrubbers and strainers that get clogged seem to be relative to the waters, and sometime even the marina where you operate. On the Alabama Gulf and Intercoastal it is advisable to clean strainers about every 100 hours or so. Even more frequently if you do no operate often. You can operate for 3 hours one weekend, leave the boat and come back in a month and the strainers will have algae growth on them. Warm waters. That does not include those times when the red tide comes. That is just another reason that a closed system is very desirable to me.

 

Closed systems have their own problems... I was just talking to a NA friend who decertified an oil rig because the keel coolers caused corrosion on the hull from the high temprature. Basically over time the coolant water etched a channel in the hull plating, causing a billion dollar rig to leave service, at least until they replace the entire thing.

Personally I have seen it all. In the Carribean we went years between strainers getting clogged, and in one bad week in Pensacola harbor I picked up trash bags in my AC strainer 5 times.

 

I posted the high pressure air or water flush of seachests because we have to use it almost daily on commercial vessels.
I still think Frostys broomstick idea is great for small craft, though not suitable when the engine room is a dozen or more feet below the waterline.

 

Comparing a cooling system on an oil rig to a trawler is a stretch but i get your point. Every action has an equal and opposite reaction. Which means, every time you light the fire in those cykinders you are ripping minute particles of cylinder wall away. Wearing pumps and gears out. All the while, the salt water is thinking of ways to eat your hull. The sun eats the topside even when all is still and quiet. Not just boats but things in general. Even the rocks around us are deteriorating constantly. The is only one way to avoid constant maintenance on a boat and that is to let someone else own it. I am not necessarily trying to avoid maintenance with a closed system. I want less through hulls. I want engines that do not have to be marinized(for 1/3 the cost). I want a system that will not flood with seawater unless i am bottom up! I do know that i may never get the system exactly like i want. But i can dream and learn can't he?

 

Neither do I like through hulls. On my Albin 25 motor sailor I added a 5 foot pointed extension on the stern. The original transom is now a watertite bulkhead. The extension is foam filled and has a self bailing cockpit.. All through hulls have been relocated to new aft extension.
Propulsion is now electric and the motors are two 80ib thrust Riptide saltwater Minn Kota permanent magnet motors which are cooled by being submerged. The rudder has been relocated to aft of original transom. There are now no underwater perforations in original hull.

 

Guys- it's a fifty footer. So sprinkle a dozen through hulls around where you need them and be done with it. It helps if you operate them all at least once a month. Even if you don't have to pump the blackwater, give the valve a waggle. Don't manifold hardpipe off a valve. Run flexible stuff to the manifold if you want to multitap a through hull. They are rated at 500 pounds load. That's easy to overload with a wrench if you have a rigid standpipe manifold and you are torquing on the upper distribution valve. So mount the manifold to some structure, don't rely on the through hull.

He'll be lucky to be able to slide his hand between the engine and the engine compartment wall. Fuel filter is probably in a different compartment because there isn't room in the engine bay. On my boat, I need a tool to move the engine coolant cock because my hand won't fit.

Most fifty footers I've seem don't have the chaseways to allow a proper seachest and distribution system. There's nothing wrong with plastic valves. They meet the same standards and you might as well use them on a plastic boat. Probably a lot stronger than the hull of a fifty footer. As several posters have mentioned, damage tolerance is a prime concern. Just a small valve connected to flexible tubing no deeper than is necessary gives good results. Use solid hose clamps, not the ones with slots cut out for the screw. They don't cut the hoses and cause leaks like the cheap ones.

And of course hang a bung on a string by every valve.

The above is small boat stuff. Sure, big boats do it differently.

Re. metal hulls- I knew that temp affected corrosion and had never seen any fudge factors on the required voltage to protect a hull as a function of temperature. I wonder how many keel coolers are pushing the limits. Should (external) keel coolers be isolated and separately protected? Should internal coolers have specific zincs located nearby on the hull?

 

Tad, i did not see your "Lloyd's" response until a few minutes ago. Thanks for clearing that up for me. The original rabbit trail started with a comment from someone who said that he knew no vessels, except large(60+) ones that had water tight engine rooms. I asked if those vessel saying that they were designed in accordance with Lloyd's standards for any oceans required watertight bulkheads, including the ER? Can you please speak to that. Also, can you speak to the issue of keel cooler temps and their corrosion effects on hulls, specifically steel. Thanks! robert

 

A proper vessel should have 3 compartments with waterproof doors. It does not mean they are air tight, engine room should have proper ventilation and all compartments emergency exits or hatches to the deck for fire escape. The less thru hulls the better. All need to have proper shut offs and filters. Sea chests are a good idea, but which is better two very large ones or a few smaller ones. But definitely not 20 something,

 

pha......

I can speak to what Lloyd's SSC (Special Service Craft) covers. Others Lloyd's rules, such as for ships, etc, I've never dealt with. The SSC rules cover small craft including yachts and small commercial vessels.

Lloyd's Bulkhead requirements are based on length of the vessel. I believe the 2010 SSC rules require gas tight bulkheads closing off the machinery space on any sized boat. Any boat over 15m requires a watertight collision bulkhead. Any boat over 15m is required to have WT bulkheads fore and aft of a midship machinery space but only a forward (of machinery space) WT bulkhead if machinery is aft. My smaller Passagemaker Lite designs only require 2 WT bulkheads; collision and forward engine room. Over 25m 3 or 4 WT bulkheads are required.

This thread gives info for getting Lloyd's rules http://www.boatdesign.net/forums/classification/lloyds-register-uk-rules-free-35454.html

 

On corrosion in keel coolers.....

In my experience keel coolers come in a few different forms. The one fitted to my boat is two lengths of heavy wall copper pipe with a bronze through hull at each end. It's fitted outside the hull planking.....that's it.....This is typical here in the temperate PNW....these work essentially flawlessly for ever.

In steel boats I've seen and designed two types. For big engines with lots of heat rejection we usually weld long sections of channel outside the hull plating, this is typical of tugs, etc. For small boats I box in a section of keel/hull bottom, typically between girders or floors. Either of these can again work flawlessly for many years. I know of one tank system that's been in service for 30 years. Another of my early steel boats had the HP tripled and the tank no longer worked so the owner went to a heat exchanger as the simplest option.

I have not come across any corrosion problems inside keel coolers, only exterior corrosion from stray electrical current.

 

Locate your keel coolers so that the shipyard travel lift straps or railway blocking cant damage them.

Interrnal tanks between frames, servicing refer and freeeze work well.....I used one for decades. One beauty of the box cooled refers is that you can use them when halled out.

Refers run constantly in harbours and are the most prone to pickup junk in the seawater coolingf system