Excuse my ignorance but...

Why are boats still sucking up lake water to cool the engines? What’s the advantage? With all the problems winterizing and impeller's going out, etc. etc. Why not just use a normal radiator system with antifreeze? Seems to me you could put a nice big fan in to get some airflow over the radiator and have no problems. What am I missing?

They have closed cooling systems for the engine (works like a radiator). I think a lot of the problem is space. The closed cooling systems are bulky and cost about $1000-$2000 more. The extra bulk makes it harder for maintenance.

On a $80,000 boat whats 2k? Can you get them as an option? I had an impeller go out on a boat in powell this summer, it cost me about 800 dollars to run down and fix it i.e. gas, hotel etc etc. And I changed it myself. Seems crazy to have so much riding on a little 40 dollar rubber pump.

that's why you keep a spare on the boat.....

closed cooling systems also run hotter than using lake water to cool..

seems crazy to me to spend $2000 to replace a $20 piece of rubber. Maintain it, it won't go out.

Not to mention if you suck up some debri and it clogs your intake.

Gunner, I think its one of those 'if it aint broke, dont fix it' things. Companies could spend more time on developing hassle free systems, but why when they can figure out where to put more chrome on the boat.

Closed cooling systems still use an impeller to pull water into the heat exchanger and not they do not run hotter, at least they are not supposed to. They also do still need to be winterized.

How about like a car. They don't need to be winterized. You can add some air intakes on the side of the boat and other areas for the radiator. I could see it happening. They would have to develop a good system that takes the full throttle and shut downs often.

Yeah learned my lesson, I’m replacing impellers each year. Just found this info here is a link, answered some of my questions.

http://www.boatpartsinfo.com/cooling-systems.html

The debris clogging the systems seems to be a problem as well. I’m no engineer, but it seems entirely possible to put a large fan in front of a radiator, some air scoops on the boat and you would be good to go. You could eliminate the heat exchanger altogether. Once the initial setup was done, it would seem to be fairly inexpensive to mass produce.

(Message edited by frr on October 17, 2007)

lol, water freak you beat me to the punch, thats what I was thinking...

With a radiator in there, even with intake and outtake air vents, think about how hot the engine compartment would be though. Nearby seats, storage, etc. being affected. For all that, I'll stick with the water cooling.

Out of curiousity, can you have a closed cooling system and a hot water shower? I LOVE my hot water shower!

An air cooled system is not nearly as efficient as a water cooled system plus it would eat up space. Where would you put the radiator, fan, incoming air and exhaust air ductwork.

You just cannot beat the simplicity and efficiency of a direct fresh water cooled system.

Closed systems do cost more and are good for salt water conditions. The system itself is quite simple but does require maintenance.

I'm not sure why you don't see heat sinks like Gunners keel cooler for corrosive environments.

Carry a spare impeller and get a strainer if you need one. I also install a new impeller every oil change. That is the best system to date.

What I can't figure out is why it's taking so long for a manufacturer to put a open cooled turbo diesel in a boat.

Constant cool water across an intercooler would be a turbo motors wet dream.

What if you mounted the radiator below the swim platform and put some type of grill to protect it? You could eliminate fans altogether as it would be submerged in cool water.

as if the engine isn't loud enough, why not load some radiator fans in there too. Water cooling works too well, especially for idle or slow speeds - water cool things down like 26times faster than air to begin with anyway.

Plus, winterizing a boat is WAY too easy - what's the pain in draining the block once a year and running antifreeze through? Takes 10min tops, plus if you have to change the oil anyway what does it matter?

Yeah, where are the turbo diesel engines in boats? With the torque advantages of diesel, seems it would be a great fit with boating, not to mention the fuel economy. They are putting turbo diesel engines in production aircraft now, and cutting the fuel burn in half.

Turbo and super charged diesels are very common in larger boats and have been forever.

I should be more specific, small v-drive boats. Where are the turbo diesel engines? You are spending 50-90k on a boat for a relatively inefficient gas powered engine. With all the ballast high drag devices thrown on wakeboard boats why not put a Cummins td in the boat; mount some type of radiator under the swim platform, put on a small h2o pump to keep water circulation over the radiator when the boat is at idle. Why not?

Why put a radiator in a boat when, in effect, the lake you are sitting in is one big radiator already??
Think about it.
Closed cooling systems are basically radiators (called heat exchangers) for boats. We still have cool the "radiator" somehow, and since we happen to be sitting on an unlimited suppl;y of COOL water, gee maybe we should use that?!
Given that obvious gem of information, then how do suck the cool water out of the aforementioned lake into the aforementioned "radiator"?
You guessed it, an impeller. I guess we could use electric pumps instead, but guess what even they have in them? Impellers. Different style, I'll grant you, but impellers none the less.
And, since every boat made has to suck water out of the lake somehow, why not use the already proven method of extracting said water from said lake. Brilliant!
Go buy a spare impeller, leave it in the boat, and change often. Problem solved.

All right smart @ss, First I rent wakeboard boats, it is not feasible to just throw a spare impeller on a boat and tell em to just change it when they have problems. Second, the whole point is why pull Shi* up in your engine with an impeller that constantly needs replacement when you can you can have a fully enclosed system.
Third you did not fully read my post or understand it, but the radiator would be submerged in the water, hence no need for an impeller, get it? This would be as simple as an impeller but no need for winterization, and give you the ability to go from salt to fresh water also you could run your boat out of water. Overall this would reduce maintenance cost considerably and increase engine life.

The whole point is a closed system, just because you are riding on a body of water doesn’t mean sucking it up into your engine is the best way to cool it.....

(Message edited by frr on October 17, 2007)

I think the biggest reason isn't the motor it's our exhaust's. As stated above there are already a lot of closed cooled engines on the market (I've got a PCM ZR6 that I love) but that only keeps raw water out of the the engine block, it still has to use raw watter for cooling the exhaust. On a car the exhaust is not closed up in a tight space and therefore is able to be cooled by the outside ambient air, you could add whatever radiator you want with monster air intakes and you're still not going to be able to pull enough heat out of the exhaust headers to keep them cool under the engine hatch in the boat. Bottom line is for now raw water cooled exhaust is the only / most efficient way to keep things operating. I too wish there was a better way but at the moment I don't see it and believe me if it's not available on 100 million dollar yacht's the fact that we pay 80 grand for our boats probably won't push the industry...

good idea id buy a boat with a cummins in it.

course a marine equivalent diesel engine would prob cost an extra 15k how many of you would buy it?

even the diesels have water cooled exhaust...

Some guy on here has a diesel x-star that burns like 4-5 gallons per hour. How long would it take to make up for the extra cost.

I have a gas VLX loaded down time to time that gets 4-5 gph so quite a while. It has the 340 monsoon and we use stock ballast plus maybe 500 additional plus crew. I don't see the point if thats the usage. What are the rest of you burning? 8-10gph

I don’t profess to know anything about boats, just trying to learn more. Cooling the exhaust seems like the challenge...

I found some marine diesel engines, anyone know the costs associated?

http://www.cmdmarine.com/index.html

Man, don't hate the Fresh water pickup - best way to heat up the cold lake water here in MN.

Ferrari's on the lake, or worn out junk....

Hire a maintenance guy. "try to learn more." Its not that complicated. Routine beginning-of the-year-maintenace will not go away if with a diesel powerplant. and a radiator under the swim platform wont be in the water when your underway. Its not that complicated.

FYI The cost analysis of new diesel boats vs maintaining the ones you have would be interesting...

here you go gunner, under water radiator for your boat. Get some jet boat headers and your set
http://www.flagshipmarine.com/keelcool.html

Does not necessarily resolve all pump issues. I've rebuilt both fresh water pumps on my diesel inboards at less than 1000 hours and replaced one seawater pump. Unlike a simple impeller change, your not getting home without a tow when a coolant pumps malfunctions.

Gunner, check the size, weight and power output on those cummings diesels. Great engines but big and heavy.

You need to look at a Yanmar, Volvo or some other higher revolution, lightweight/duty diesel. Many diesel experts will tell you to lower your life expectancy on those engines.

For ski boats and anything under 30 feet, I'm sticking with gas.

I just sold my 1997 Mariah Shabah runabout that had a closed cooling system that was great to have. No real bulk, just a simple intercooler that still ran the lake water through it. The nice part is that if you need to winterize like I do in Canada is the it only takes a very short time. I only needed to worry about the leg and manifolds. If something had been missed you would only crack the manifolds and not the block.

A Yanmar 315hp turbo diesel inline six will cost you in the 20-25 range with transmision. I think the guy that put the yanmar in his Xstar used the 8.1L tranny that was already in his boat.

Nacho, whoo chill there buddy... I never said that I was planning on buying a diesel boat or building one etc. etc. etc. Just bored on a layover in a hotel room trying to pass time bs-ing about boat shi!.

Yeah I had one impeller go out because folks start the boats out of the water after they are instructed not to. I.e. the impeller requires h2o to lubricate it. Ahh the joys of rentals.

yea, i'm sure its a pain in the ass keeping the stupid factor from taking over when you're dealing with the toy rental public.

Got any "cover your ass" clauses in the ppwk?

Gunner:
I really wasn't trying to be a smart @ss...OK, maybe a little, but the point was more on the line of trying to re-invent the whell when the wheel only needs an occasional grease or two.
That said, I surely don't envy trying to keep up with maintenance on a rental fleet!
I know what I've done to the occasional rental car in my dark days, so I can't imagine what a bunch of beer'd up idiots would do to a rental boat!

ahh yes rental cars... always a good time... he he he