Raw water cooled or FWC

[Bruce San]

Am considering the purchase of another boat. I've been using and maintaining outboards since the '70s. The boats I'm looking at now are twin screw straight inboards. Some are raw water cooled and some are closed loop FWC. I understand the basics of each. I'm wondering about the advantages/disadvantages of each and would appreciate an expert opinion.

thanks!

 

[DukesFin]

Re: Raw water cooled or FWC

Am considering the purchase of another boat. I've been using and maintaining outboards since the '70s. The boats I'm looking at now are twin screw straight inboards. Some are raw water cooled and some are closed loop FWC. I understand the basics of each. I'm wondering about the advantages/disadvantages of each and would appreciate an expert opinion.

thanks!

I'm not an "expert" but for me... I boat almost exclusively in saltwater. If I had a FWC, I wouldn't have to worry about corrosion NEARLY as much.

Just my two cents!

 

[Reel Poor]

Re: Raw water cooled or FWC

Since your asking for advice on FWC or RWC I'm sure your looking at gas engines. My advice would be to stay away from the gas and look at diesel propulsion. Believe me, you will be glad you did.

To answer your question FWC hands down. Then replace exhaut risers every three to four years, as they are still rwc cooled.

The only disadvantag to FWC engines that I can think of would be that there are more componants bolted to the engine, making it slightly harder to work around. And you need to carry extra antifreeze on the boat.

 

[ron7000]

Re: Raw water cooled or FWC

FWC'ing "should" increase engine block and cylinder head life but most of the time other things are the result of engine failure. The benefits of FWC are dependent on the application and the environment. If it's in salt water then FWC is a good thing especially if the boat gets used a lot and sits in the water. If the boat is trailered then FWC may not be worth its cost since you can just flush the motor after every use. Some downsides to FWC are that it takes up space in the engine, it can add complexity with hoses and manifolds, and the heat exchangers don't last forever and are rather expensive. And it's just another thing to maintain and spend money on. The good thing about FWC is that you shouldn't have to worry about corrosion inside the block and heads, and maybe part of the exhaust manifolds depending on the system, but that's only if the FWC system is maintained. So I wouldn't automatically hold a FWC motor in higher regard than a raw water cooled one, I would consider where and how the boat is used.

 

[Bruce San]

Re: Raw water cooled or FWC

Thanks Guys! Great info.
the boat will be salt water use. And yes I have been looking at gas motors. primarily because the boat make I have decided I can't live without is the '70s/'80s Bertram 28 and most of them are gas. Unfortunately the diesels are a little out of my reach pricewise. Not out of the question if I can find one priced right. I would prefer diesel due to efficincey, torque and safety. Apperently re-sale is also a factor as the dielsel powered boats are twice the price of a gas powered.

Reel Poor, nice avatar. Looks like my dad. Judging by your response.....can I assume all diesels are FWC?

 

[Bruce San]

Re: Raw water cooled or FWC

Just curious but, what about the diesels and FWC? Or am I in the wrong forum now?

 

[Reel Poor]

Re: Raw water cooled or FWC

The vast majority are FWC. Actually none come to mind right this second that arn't, but i'm sure someone will pipe in with an example. Engine life is also about 2/3 times as long.

BTW, Your dad must be one gooooood loooking feller also. Thanks,,,,,,,LOL:=

 

[Bruce San]

Re: Raw water cooled or FWC

Interesting......how many hours could one expect to get from a properly maintained FWC gas motor?

And yes, dad is one handsome devil!

 

[Reel Poor]

Re: Raw water cooled or FWC

Top of the line maintainance and nit picking the little things, 1500 to 2000 hours. Typical engine life is probably around 500 to 600 hour due to neglect of some sort, and with raw water cooled its typically catastrophic.

 

[Bruce San]

Re: Raw water cooled or FWC

Understood. thanks for your input! I think I may start saving my pennies until I can afford diesel. 8)

 

[Bruce San]

Re: Raw water cooled or FWC

Sorry, I can't let this go.

The more I think about it, well anyhow...... The boats I've been looking at that are priced where I thought I'd get a deal are gas powered with engines in the 1000 to 1500 hour range. Probably close to the end of reasonable service life?? Who knows what kind of maintenance they've had. So a pair of long blocks, manifolds, risers, rebuilt carbs, starters, alternators, hoses, plug wires, etc. has got to be worth what? $4,000? $5,000? and that's with me doing the work. Have I left anything out? I hate putting old hoses and wires back on a new or rebuilt block. I guess what I really should do is learn more about diesel marine engines.

I'm open to suggestions for a good source....book? a forum like this would be ideal.........

 

[tommays]

Re: Raw water cooled or FWC

Bruce

You dont want to learn to much about marine diesel power the price is vastly more than a GAS motor

(A 120hp merc diesel is 8000 dollars more than a 135HP base gas motor)

AND they have even MORE abilty to self destruct from water in the fuel and water anywere it should not be



Tommays

 

[Bruce San]

Re: Raw water cooled or FWC

Yes, I'm well aware of the initial cost implications. I've been shopping for some time. It just seems that every Old Salt and charter captain I talk to tells me to go deisel. I do want to learn more about diesel marine engines. whether I can afford one or not remains to be seen. I figure knowledge is GOOD. I realize I can replace a gas engine more than once for the initial cost of a diesel and I have never been afraid to turn a wrench but, this boat (once I buy it ) will be with me for many many years. I want to use it not work on it.