Decent looking 18?

[Tony]

Interesting 18 on ebay, notice how the exhaust is routed outboard thru the stern. Can anybody tell us more about this engine? The owner says 300 hp, it looks pretty clean. Also, aren't the tabs too far outboard, likely not in the water at speed?

http://www.fuelmedia.com/donziclassic/back_side.jpg

http://www.fuelmedia.com/donziclassic/engine.jpg

[tailwind]

Hi Tony:

I too have this example with the exhaust routed similar on my 91 18", with the exception of perhaps the "Corsa" quick & quiet. Note the rather wide displacement of the exhaust! I will however dispute the 300 HP claim, as I can only turn a 14-3/4 x 21 Viper @ 4200 rpm with a
GPS speed trimmed out at 61 mph. I would estimate the HP around 275 considering the elect.
Ign, 4 Barrel carb, and perf. exhaust. Having tried numerous props, this is the best comb. so far. BTW I guess I should add an extra " for the cup.

[Stix Magill]

Tony,

I can't help you with the HP numbers, but the trim tabs are OK where they are. At high speed, you don't want to be messing with trim tabs anyway. I use mine to level the boat at slow to moderate speeds with an uneven starboard to port weight distribution and to avoid porpoising in the 30 to 40 mph range. beyond the porpoise range, they go all the way up. Isn't this what most of you guys do? Hey, I'm new so feel free to correct me.

I don't know the value of this boat, but I can tell you it LOOKS very, very clean and if I was in the market for an 18, I would be serious about this one!

[Brad Lyon]

Tony,

I looks like the trim tabs are in the same location as on my 1993 18. The boat looks exactly like mine with just a few exceptions.

Brad

[Formula Jr]

Scott, LIKE WE NEED ANOTHER SCOTT ON THIS SITE, :D

Tabs are very useful at WOT. At least they are to me. Brownie made a recent comment about hooks that I am still thinking about, but deploy the tabs so that they are just kissing the water at WOT, and you may find that the boat is more stable and can correct better in quartering seas and odd angle waves. They extend the hull when used like this. And the two rules of off-shore go-fast are length and HP. You can also "Pinch" the transom down to some degree by upping the drive trim and pushing down on the tabs. You lose speed, but you gain side to side stability.

If you look at my avatar, you can see that tabs can act as stern lifts and raise you up so less of the boat is in the water. So the interaction of tabs and your Drive trim can make big differences in how a boat "airs out" at WOT.

There are two divergent philosophies on application of trim tabs. You have the "Old School" way of looking at them, Big Boats, optimal planing speed, trim and list correction etc; and then the "New School" applications on smaller fast boats. Bennett doesn't talk about applications or uses in small fast boats. So they just recommend the old school placement and uses and treat an over-powered small boat in the same manner as they do a 45 footer. In this boat, new school says place them as close to the keel as you can with out interfering with steering and deploy them as an extention of the hull which will increase you running surfaces.