Why Marinize

Hi,
bit of a silly question.
I was planning to buy 2 x ford 1.8 diesels to replace my 2x perkins 4108.
1 of them needs an expensive recon jobie.
However I am wondering if I really need to buy a marinizing kit for the fords.
I'm thinking if I get the engines for around the £50 - £100 mark just to use them. I've seen this done in Thailand. When the begin to rot too much I'l just get some others. I think I would be lucky if I used the boat 60 hours a year. As opposed to spending £2400 for the marinsing gear.
What are the disadvantages in doing this ?
Is it dangerous ?

Thanks

 

Safety!!

 

Why is it unsafe ?

 

My car doesn't use a £1300 cooling system. Just a radiator. Why is it unsafe to use the same principle with seawater. These components are dirt cheap.
If it is unsafe I will pay up but I've not read or seen anything against it. Except the obvious extra wear.

 

The safety thing has more to do with the HOT exhaust. If you can get rid of the Exhaust without burning up the boat or the Passengers, you should be OK.

 

With a couple of hunks of simple water pipe you can use keel cooling.

My 215 Hp DD requires 2 -21 ft hunks of 1 1/2 pipe to cool even in FLA waters. You should be fine with MUCH less.

The exhause can be wrapped with an asbestos like material , and taken up & put dry stack style.

An automotoive muffler works well to reduce the noise.

Workboats use the keel cooled & dry stack for lowest cost and ease of operating in freezing conditions.

FAST FRED

 

Hi,
Sorry Fast Fred I'm not sure what a dry stack is. My boat is a GRP 28' circa 1972 . I am planning to replace the water pump with a jabsco to cool the engine block with the raw seawater and then I'm thinking of trying to cool the exhaust . I plan to modify the cast iron manifold to take water injection. Having not done it I don't know exactly how. I've been tring to find if someone else has a DIY diagram to see if what I think should work in theory is possible.

 

Back in the 1950,s a very popular Ford V8 conversion used a very small 1/8 inch pipe tapped into the Front of automotive type (cast brass, log type) exhaust manifolds to enter a small amount of water to "steam cool" the manifolds. Raw water from the Engine was dumped into the exhaust pipes after the manifolds.

System worked very well and the Steam probably even cooled the exhaust valves.

 

With NO water , the exhaust is just taken with a 90 bend up thru the deck , to above head hight.

The exhaust WILL need a screen or similar to avoid gettin gurned if touched.

FAST FRED

 

Following link may give some understanding about the problem.

http://www.boatsafe.com/nauticalknowhow/cooling.htm

 

Crikey I'll be like an old chugger.
I plan to attach a pipe to the exhaust manifold with a second pipe around that one with the water system cooling the outside of the pipe before coupling it to the exhaust hose. This is the prinicple.
Im just not too sure how long this pipe should be. I think its called elbow injection ? Well something to do with elbows.

 

You have to use a heat exchanger. The one side of exchanger must be connect with engine with fresh water, and other side with sea water. The connect must will be with water pump. The size of heat exchanger depend on power of engine.