90's Z or ZX with Pad

[SilverBack]

Which of the 90-99 model 22-28' Z or ZX boats came with a pad in the hull?

[The Hedgehog]

Funny you should mention that. Here is a pic of a 25ZX hull with a pad. It is not a full delta pad but it is about 10" wide. The boat is a 1996. I did not know that Donzi used any of these at that time. I wonder if this was some sort of special hull.

Tex and I were comparing notes and wondering if some of these boats had different layups. His 27ZX was 3 # off mine. His is a step hull and I know that that is different, but the flex in the side of his hull seems to indicate that it has less glass.

[SilverBack]

What do you call that kind of pad? I didn't thin they had pads or steps until 97. Did they do a pad hull on a non step? I guess they did if this is a 96 it sure doesn't have any steps in the hull. Did they build some boats with a different keel in the hull? wouldn't you have to have a totally different mold to do a pad like that? When you say less glass...do you mean that the hull is thinner to save weight?

Maybe Mr.X ,Blown Crew Cab, Buizilla, RT SE or some of the guys in the know about the way Donzi boats were made will chime in!

[BUIZILLA]

I don't know the year to year build idiosynchrisy's of the ZX's, but there WAS another 25 for sale in the Ft Myers area a couple or three years back with the same pad setup.

[SilverBack]

Was this a ZX-25? Have you seen any others with this type of hull? What do you call this kind of pad?

[mjw930]

Was this a ZX-25? Have you seen any others with this type of hull? What do you call this kind of pad?

Honestly, that pad looks like a plug they put in the mold. Without a wider angle shot to see if the inner strakes are full length or if it has a notched transom my guess is has some "interesting" handling characteristic's. Certainly a work in progress from a design standpoint IMHO.

[SilverBack]

What do you mean by saying that they put a plug in the mold. Did they just fill some of the mold before they made the boat? Is this normal? Do they do this with all models? What would that do for the performance?
Thanks!!

[mjw930]

What do you mean by saying that they put a plug in the mold. Did they just fill some of the mold before they made the boat? Is this normal? Do they do this with all models? What would that do for the performance?
Thanks!!

When boat builders play around with different bottom designs they routinely put plugs in the basic mold. Once they are happy with the design they either make the plug permanent or use a hull popped from the modified mold to make a new mold.

As for performance, it's a crap shoot until they pop the hull and at least rig a partial deck and power and do some testing. It's trial and error a lot of times and they sometimes destroy the hull if it ends up being unstable. This modification only looks like they were playing with pads to get more lift (i.e. more speed). Since they produced it I would guess they deemed it safe.

[SilverBack]

When they plug a mold to make a pad like this do you raise your x dim to take advantage of the pad? How does the pad effect the performance?

[mjw930]

When they plug a mold to make a pad like this do you raise your x dim to take advantage of the pad? How does the pad effect the performance?

Typically yes, you can raise the X when you go to a pad because the water is exiting the bottom higher than it would with a full V. To go even higher you can add an extension box, boats with a notched transom like Fountain and Velocity achieve the same thing as an extension box with the notch.

The down side is performance coming onto plane and possible directional stability. The pad adds lift to the rear of the boat and a higher X reduces your leverage on the bow.

If not properly designed you get into a serious bow steering problem. If designed properly these hulls are much more efficient and easier to drive at speed.

Pad bottom boats also tend to be less forgiving in the rough stuff, they slam or pound more on re-entry.