Conference unifix::sailing

    Re: .0
    	Phil,
    		Did you ever do anything about a water lift muffler system?
    I am planning on replacing my Atomic 4 with a rebuilt this winter. I
    will also be re-doing the exhaust system. Most of the schematics I have
    seen in various manuals and publications recommend the water lift
    systems. The Sept/Oct 91 edition of Wooden Boat has a write up
    describing such a system. I called a place in Seattle that carries
    these mufflers. They told me that they just need to know what size
    exhaust pipes/hoses you are using. Some of the marine catalogs carry
    a water lift type muffler but it specifies 25 hp or less for a gas
    engine?
    
    -John

    I installed a Vetus muffler and Water Block system on my Atomic 4 in my
    1965 Columbia 29 over 7 years ago and have had absolutely no problems 
    with it.  The boat has sailed over 15,000 mile since then.  Still perfect. 
    
    Expensive, but worth it.
    
    Good luck,
    Jeff
    
    

    
    I have the same Vetus setup in my 30' sloop, and agree on the quality.
    When I upgraded my engine 5 years ago, it came with another complete
    Vetus system, that is sitting somewhere in my garage for "spares",
    if you can use it I'm willing to sell it.
    
    Henk
    

    Most of the sources I spoke to carry the Verna Lift type muffler made
    by Vernay. How does the Vetus one compare in price and where are they
    sold? 
    
    Re: .3  I guess the specific unit depends on the size of exhaust
    pipes/hoses used. I will send you a note when I get to the point of
    re-doing the exhaust system and know sizes.
    
    -John

    My plans for my exhaust system are starting to come together. I am
    still wondering what to use for insulation on the "dry" section of the
    system. Most of the publications mention wrapping it in asbestos and
    foil. I hope there is a replacement for asbestos for todays
    requirements. Does anyone have a clue what to use and where to buy it?
    
    -John

    I thought we were talking small (20-30 hp) engines...doesn't it use a
    seawater injected/cooled exhaust? If so, what do you need to insulate?
    Of course I know diesels, if this is a gas engine I'm pretty ignorant.
    I used a BIG exhaust blower to provide three functions: suck diesel
    fumes out of the engine compartment over the transom, and, when
    motoring for long stretches, keeps the engine compartment cool, and
    provides a nice load to the alternator to keep the batteries from
    frying. -.)
    
    Henk
    

re .5:

The stuff around my exhaust pipe looks like woven fiberglass. Try 
calling an engine dealer (eg, Hanson Marine in Marblehead) and asking 
what they use.

re .6:

>>>    I thought we were talking small (20-30 hp) engines...doesn't it use a
>>>    seawater injected/cooled exhaust? If so, what do you need to insulate?

The short section from the exhaust manifold to the seawater injection 
fitting. On our 25 hp diesel this is about six inches long. It would
undoubtedly get hot enough to be at least somewhat dangerous without the 
insulation.


>>> ... and provides a nice load to the alternator to keep the batteries from
>>> frying. 
    
A better solution would be an alternator regulator that reduces the 
charging voltage once the batteries are charged. The float voltage on 
the Ample Power regulator, for example, is user adjustable. At full 
charge something less than 3 amperes is going into our three batteries, 
not enough to damage the batteries even with extended engine 
running.

    re: .6
    Yes, I am talking about a wet exhaust system. The issue is the fact
    that I suspect the demise of my Atomic 4 was due to water backing up
    into the manifold and seizing the valves. 
       Several of the marine exhaust schematics I have seen recommend
    adding a loop which rises and falls about 4" to 6" in the dry section
    of the system. The water is then injected at a point which is isolated
    from the manifold exit. You also need to imagine the system on a ~45deg
    angle (port and starbord tack) and design a system which guarantees
    that no water can back up into the engine. Anyway, it is this "dry"
    section that needs the insulation. (It gets hot enough to fry an egg!)
    
    -John

    By golly, you've finally explained something I hadn't really understood
    the reason for... On the 25 hp. Vetus engine (Mitsubishi block with
    Dutch-designed British, French, German and Dutch stuff bolted on), the
    seawater goes through a heat exchanger (the engine proper is cooled
    by an antifreeze/fresh-water mixture). The outlet of the heat exchanger
    is an integral part of the exhaust manifold, i.e. no separate pipes or
    fittings, and the manifold has never gotten hot enough to even blister
    the paint on it. This means of course that there is no up-facing loop
    or elbow as used in my old Yenmar engine to keep water from draining 
    back into the cylinders...but the Vetus instructions made me place
    the muffler 10-15" below the manifold hose outlet, then run the
    muffler outlet hose up to the top of the lift, 24-36" above the water
    line. The bottom of the lift then exhausts thru the transom. It seems
    that the whole scheme has kept seawater out of the engine quite well
    for six years!!!
    
    Alan, I agree about the regulator and I have one...however, I once had
    a regulator fail due to overheating and the DC blower motor is great
    for my peace of mind...
    
    Henk
    

re .5: exhaust insulation

This stuff is available by mail order from any number of places that 
sell automobile racing parts and accessories. There are several ads for 
it in, eg, Stock Car Racing magazine. It is usually called header wrap.
It apparently comes in rolls of varying width and thickness. Price per 
roll seems to be in the $30 to $60 range. One roll will probably be a 
enough for several installations.