kool keel diesel engine

Originally Posted by cthippo

Is there a general equation for area of cooler vs HP or KW?
Does coolant flow velocity make a difference?

Read the posts and get the answer! It was already said just one page back!

Coolant flow direction makes a big difference too, and that is possible to design proper.
That too was mentioned just a few posts back.
Maybe you better put the drivel kings on your ignore list instead?

Originally Posted by Landlubber

Carlos asked "i like to know if it's better to fit the engine (kubota 28hp diesel)", now that little sucker can simply use a built in double bottom lengthwise section instead of cooling pipes, I have done it up to 45 hp on a Daihatsu in a 34 foot boat, carlos is building a 7m boat.

That will sure function John.
I have missed the 20hp figure in singleprop´s post.

Originally Posted by TeddyDiver

Dave Gerr advices about the following in the Boat Mechanical Systems Handbook:
For a steel boat, painted bottom, displacement speed under 8kn. Seawater temp up to 29C (85F) 0.037sqm/bhp equals (0.4sqft).
With 28hp you need ~1.04sqm of keel cooler area (I rounded up a bit some..)

As a rule of thumb, -with aluminium the area is half of the steel area and with copper half of the aluminium area..

Make it easier Teddy (and safer),

as I said before, 100hp require 2m² in Alu, 6m² in steel, and that is what the engine manufacturers tell us (the industry).

A optimized flow* of the coolant, or tubes make a better result than a flat panel, of course.
*entrance of coolant is always at the aft end, forcing the fliud to flow against the seawater flow.
But both rules of thumb (Gerrs and ours) are worth nothing, when the area is calculated to the minimum, and one runs the engine for hours in warm waters at anchor.
Barnacles and marine growth do their part to make a minimal setup insufficient.
So, that should be done with a nice safety margin. Hence my larger figures.
And Gerrs "under 8kn" is a fault. It should be better saying at 8kn, because under 8 you slowly (pun intended) run into the insufficient range.

Regards
Richard

[carlos bairo]

HI migel.thanks for the info it's glad to exchange the idea's with people from espana
thats is a beautiful cantry i veen there lasat year ,i from URUGUAY veen in AUSTRALIA
since 1970 if your search in the forum under CARLOS BAIRO foto laibery theare some pictu
of my new boat under constrution ,neow it's been tourn over and the hull welded inside
this my email leticiabairo@yahoo.com.au to contat espanol
REGARDS CARLOS

[larry larisky]

on some steel hull we used a lot of box cooling, on the lower side of the hull, well underwater of course, with a screen. it was used on some tugboat.
i can't comment more since i don't know much about these system.

[singleprop]

I have run the calculations for skin cooler area using a couple of different sources, Beta Marine, Dave Gerr, Catarpillar cooling documents and John Deere AG-24 document.

There is quite a bit of difference in the area required;

John Deere comes up with much more cooler area than the three others engine suppliers. John Deere's data is in line with Richards thumbrules. I would tend to go with John Deere/Richard although it will require much more pipe length (if I can fit it). The John Deere document is much more specific so it makes it a very credible document to work from.

[carlos bairo]

Originally Posted by gonzo

A keel cooler is a good idea. A tractor engine not so much. By the time you fit a marine gear and fabricate a custom exhaust it will cost way more than a marinized engine.

yes gonzo thanks for the info .i need you help tu contact peple on montevideo on my return for good beacause i do not found marine forums
on uruguay ,i will take TITAN with me.,i will need information from members
on the marinas on montavideo and i velive you my have contacts.
i am a master builder naval pressure vessels 10 yers /montevideo/35yers
australia/d i r-welder consultant and fabrications / retire this year

best regards carlos bairo