Altitude & 16 vs 18

[tntut1]

Greetings to all you fellow boaters from a new member and prospective Donzi owner. I'm hoping to obtain feedback/advice on two issues. First, I'd like to acquire a 90's area Classic 16 or 18, but am unsure which craft is best. What do you guys think?

Second, I float at higher altitude (5000ft) and am concerned about what steps will be necessary to allow a 16 or 18 to run well. The ones I've found for sale are all in low altitude areas, so I guess an outdrive rebuild, and perhaps staying away from the OMC products since parts could be an issue. What do you guys think? Go Mercruiser? Would a re-prop to a low pitch be enough on one of these small hulls?

Thanks guys.

[Marlin275]

Go with the 18
more room
better ride
best handling boat in the world for her size
more room to work on the engine

Donzi first made the 16
then they made it better -
the 18 - 2 + 3

The Donzi 18 is one of the longest production run
boats in the world.

[GBond]

What Marlin said

[gcarter]

Donziweasel, who I think lives in Jackson Hole, boats at about 6K+ '.
He had some iissues, but eventually got to where he wanted to be.

For just two feet, the 18 is in a different solar system from the 16.
Unless you boat on a very small lake, the 18 is a much more satisfying boat.

[tntut1]

Thanks for the feedback guys, I'll have to look up the Donziweasel. The 18 does appear to have a better hull design correcting the 16 porposing issue, but will trim tabs also do that? The market has more 16 for sale and the price difference is notable. The 18 in some cases are twice the price. Is the 18 really that much better?

[glenncal1]

If you are looking at later model boats (16 or 18) grab one with EFI for the altitude. My big boat Searay 265 has two 6 cylinder mercs that are the MPI model. They ran good at sea level in florida where I bought the boat, they run good here in the mile high city. You will loose about 15% of your power at 5000' compared to sea level so you may need to drop some pitch in the prop.

[gcarter]

Is the 18 really that much better?

Yes!
Be patient.
And don't just shop price.

[mattyboy]

The one big advantage of the 18 is the comfort of the passenger that the front buckets give. the 16 is better at water sports and lounging around the lounge seating in the 16 gives more room to move about the cockpit but the 18 gives more room in the bilge with a V8.

the ride difference in the 2 is not that different the seating in the 18 gives a more in the boat not on the boat feel than the lounge seating of the 16. when it's rough in a 16 it is rough in an 18. When I came back from rough rides at the events the 18 owners came back beat up too come to think of it the owners of bigger boats came back beat up too well maybe not beat up but they were wet so it was rough . If my 16 had the newer 2 +2 seating I would still have it.

don't under estimate the 16 it is a very capable boat that once you get use to can be very agile and fun to drive.

you boating needs/style/area would really dictate what you need.



BTW they all porpoise 16 18 22 that is usually cured by the right prop if not cured at least controlled/ limited by the right prop.
tabs help when its rough or when the side to side balance is off. once you're used to the ride and setup right you'll use the tabs less and less

[DonziJon]

My 20' Minx...does NOT porpoise at any speed up to max speed of just over 60. I am using the Antique Merc 21" Cleaver that came with the boat in 1986. Just sayin.

[Sweet Cheekz]

I had a chance to run Mike O's great 18 at LG and it was a riot Does feel a bit bigger than the 16 but both boats ride great Like Matty said the 18 is not going to calm a real rough day over a 16 Both a very fun
Parnell

[gcarter]

Maybe I should have been more specific. It's so easy to generalize impressions.
I think the main difference is the 18 responds more positively to engine inhancements, w/less hull modifications than a 16.
After all, the fastest classic in history was a 1000 HP (OK, 940 HP) 18 w/an Arnesson. It did 120+ MPH so effortlessly. To the best of my knowledge, it had a stock bottom. It was probably strengthened, but the bottom shape was unchanged.
An 18 has the room to have the more ambitious engines. There have been factory BBC's w/a TRS drive.....
I think an 18 handles an 18" chop better than any other Classic hull.
It has almost the same interior room of a 22 w/a 4' shorter hull.

But, if you like skiing, tubing, etc., you probably can't beat a 16.

[Cuda]

My 20' Minx...does NOT porpoise at any speed up to max speed of just over 60. I am using the Antique Merc 21" Cleaver that came with the boat in 1986. Just sayin.

My Minx never porpoised either. My 22 did before I got the right prop on it. The Minx had tabs that I never used, the 22 didn't have tabs, but I could see inside the hull that it was made either for tabs or had tabs at some point.

[Cuda]

Is the 18 really that much better?

It depends on where you boat.

[RickSE]

Most of the altitude folks run a higher gear ratio in the outdrive, 1.68-1.83. All the boats that my dad sold in New Mexico came from Donzi with the higher gear drives.

[tntut1]

Thanks for all your advice guys, and I can certainly see where patience and research are necessary. The closest 16 or 18 classics are about 1000 miles away. It also seems that most are in sea level regions, so an out drive rebuild may be necessary. In that scenario I worry about the gears being available for the OMC boats and may stick to a Mercruiser. I do have two younger kids (8,13) who enjoy wake boarding, tubing, etc...and the sweet 16 lounge would be an advantage. Do any of the Sweet 16 4.3 Mercruisers come EFI? Is that a throttle body EFI rather than multi port?