Thru-hull to thru-hub, constraints for classics?

[banfield]

Hi, I'm considering buying a Classic (18 or 16)
and am curious about the feasibility of converting
them to thru-hub exhaust from thru-hull. I note
that most boats come thru-hull, but I don't like
the extra attention, and would much prefer the
thru-hub (or perhaps a combination or a choice).

What are the combinations of engine and drive that
make this either difficult or impossible?

What does one need to do to install the required
systems? How much would that cost professionally
(parts and labor)?

Thanks, Don Banfield

[JP BRESCIA]

I don't understand. :cool:

[mattyboy]

Why?

the newer classics come with silent choice as an option( best of both worlds) and I've seen some 18 and 16 with merc's without thru hull why not look for one of those and not doing any engineering, the older ones with the Volvo I would guess to say would be impossible( so now let madpoodle produce the pic of the 16 with the volvo and thru hub)
I would look for one with silent choice, Donzi's and noise are like beer and pretzels, words and music, t and a
good luck
Matt

[Danny]

Dan
I can only speak to the issue related to Volvo.
I am converting my 21 GT to a Captain's choice or Silent Choice. I presently have a 280 Volvo with a 350CID Corvette enine with rear riser exhaust manifolds. There is no room between the rear riser manifold and the transom to install either Choice system so I will have to change the manifolds to a centre riser manifolds. On the Volvo to get below water exhaust you need to take the blocking plate off the transom plate, install a Y pipe (from Volvo) that run from the the lower hole in the transom plate up around the bell housing and then to each side connected with 4" pipe to the manifolds, I will install the choice system in the 4" pipe between the Y pipe and the manifolds. You also need the right fitting and exhaust bellows to get through the transom plate and connect to the outdrive.
I lucked out and bought a 280 T drive (compete with transom plate and hydraulics) from a guy that was converting to a new Duoprop and got the centre rise manifolds, Y pipe, bellows, pipes and fittings in the deal.
I am not sure but I assume I am going to have to remove the engine to install the Y pipe but I want to do some other things in the engine compartment and put in the new transom plate on the way by. None of this being particularly difficlt but time consuming.
I have no idea of the new cost of these parts or the labour time but it is definetly not a cheap procedure.
Far cheaper to convert from below water to thru-hull than the other way.
Hope this helps .
Danny

[Donzified]

I do love the rumble of the Donzi.It would be nice to have the choice of not waking up the camp site when I go for that early morning BLAST.Oh how SWEET it is.The morning due wipes up so nice on the deck...or leave it and wear it as you reach top end! :D

[farmer tx]

I installed Rex Marines exhaust diverter this spring. It took about a day. You have to remove the engine and install the exhaust wishbone, and realign the engine coupler with the outdrive.(the specs. for the alignment tool are on a prev. post) The reason I used Rex M. was because the actuater is gear driven and not air opperated. Also the diverter is anodized and not chrome plated. The only thing i didnot like was the toggle switch that came with the kit. I found a rocker switch at Pro Bass shop that was mom-off-mom to replace it with. So far i really like the setup. I am also trying the new style exhaust bellows (with one clamp) to reduce back pressure, since it's on a 454mag.Hope this helps. The Rex diverter was about $750. and the wishbone was $50.(they were over stocked usually $235. from Merc.) http://www.donzi.net/photos/mhorne05.jpg

[banfield]

While I do understand the allure of hearing the engine and its power in full glory, I seem to like going out on my boats later at night. I don't like the idea of waking up everyone nearby to listen to me out playing.... hence the desire for the thru-prop exhaust.

I'm not looking to buy a new classic, but rather a used one (my budget is the biggest issue), so finding the right one in good condition is the challenge... So I was wondering how much weight I should put on finding one already with the thru-prop exhaust...

By the way, the reason I'm looking for a donzi is less for speed, more for style, but the single largest driving factor is what I'm told of their ability to handle waves and chop. I'm sick of my current boats slapping tendency (1985 Chris Craft Scorpion 18')... makes boating suck. The old Starcraft 16' (1967 with a 120 merc) that I grew up with was so much more fun...could hit a wake, maybe even get the prop out of the water and smoothly return without losing kidneys or fearing for the hull... no way can I do that with the Chris Craft.... I'm told I could with the Classic Donzi's... true?

Thanks!
Don Banfield

[Ranman]

Yes it's true. The Classics can handle big water FOR THEIR SIZE. This doesn't mean you won't take a beating in the rough, but there's no other 18 that can hold a candle to a Donzi in bad water.

My first Donzi was a 96 with thru-prop exhaust so they do exist, although they're rare. It was certainly a quiet ride. I have to say that I have only ever seen two 18 Classics having only thru-prop. I think they use it more on the 16's since many have a V6 and the sound is different. I would think it would be more expensive to convert from thru-hull to choice/thru-prop, but the thru-hull boats are plentiful. Conversly, I feel it would be cheaper to convert a thru-prop boat to choice exhaust, but again, it will most likely take quite some time to locate an 18 without thru-hulls.

Another option may be to install some switchable mufflers to quiet the noise of a thru-hull boat. I don't know if these work real well or not. Other members I'm sure will offer excellent suggestions. Randy.