Launching a Donzi ???????

[Donzigo]

This weekend, while screaming past a 48 Hatteras, I was compelled to launch the Z-33 off of a 4/6 foot wave. The Z-33 weighs 8,000 lbs. or more and was loaded with fuel, too. It has through hull water pickups that go to sea strainers then to the Jabco water pumps. The boat was out of the water MAYBE, 2/3 second at the most. I did pull off the throttle, (which was at 3,000 RPM, I ususally run them 3,600 RPM), so as not to red-line the mills.
And, when I come out of the water, the sea strainers are full of water, for sure.

So, what's your best guess as to how many seconds I could be out of the water without burning my water pump impellers up?

I'm always thinking about this problem, when I think about launching that bad-boy.

[Mr X]

Richard,
I would guess about 20 Minutes. :wink:

Seriously I would bet that the sea strainers full up instantly due to the forward movement thru the water. The impellors never lose water......with that little bit of air time.

[CDMA]

Richard,

Fly her as much as you want. Just get good on the throttles. Remember you can pull too far back too....

Chris

[cigarette30]

I have not heard the impellers being the concern, half as much as the drives. Even with the best "throttleman", it is still rough on them with "re-entry". I have seen the 2-4 second "air time" in my 30' without problems, still change impellers every 50 hours regardless. Are you running "heavy duty" newer drives, (X's or XR's) if not go easy, it may get expensive.

[Tony]

I guess I just cannot comprehend 4 seconds of air time!

[cigarette30]

Tony,

If your ever in our area, your welcome to a ride. Our inlet, bay to ccean has 4-6 footers (spread apart), it's common place. Hold on, and smile! (and call the mechanic)

[Tony]

Sign me up Cig 30, it sounds like a real rush...and thanks for the offer!

:shocking: :shocking: :shocking: :shocking:

[HyperDonzi]

Richard,

Fly her as much as you want. Just get good on the throttles. Remember you can pull too far back too....

Chris


How is that dangerous?

[Air 22]

Answer's to your question.... :yes:

[Blewbyu]

Ouch!

[Steven Cohn]

Launching is cool! I've forgotten to open my through hulls and have cooked a few impellors. It only takes seconds to empty the strainers (mine are Jabscos w/approx one gal. of water in each of them). I'd say 30-40 seconds before the rubber impellors break or begin to loose integrity. That would be my guess and besides impellors are easy to change. Now, removing the scorched rubber from the pump housing is different story. But that's boating.
Steven

[Air 22]

if u cook an impeller... :frown: backflush engine w/ garden hose to force out the small pieces. You only want water in there.... :eek:

[blackhawk]

How is that dangerous?
I think what Chris is saying is you should TRY and have the wheels spinning as fast as the boat is moving upon re-entry. We all know that free revving the drive and re-entering is hard on the drive. But pulling completely back on the sticks so the drive is going slower than the boat is also hard on it. Did I explain that right? :)

[blackhawk]

I guess I just cannot comprehend 4 seconds of air time!

Tony, I was out with a friend of mine in Lake Michigan running 4-6 footers in a 19' boat. We were running close to 60 mph(maybe more) at times and easily getting 3-4 seconds of airtime. That's a little boat to be flying like that but it took it well. You wanna talk about a rush!

[Blewbyu]

Came up behind a Bertram 42 last year.Dead center.He was logging about 22 knots and still not on a full plane,bow high.Turned stbd about 100ft behind him and climbed his stern wake doing about 50,only to realize that his quarter wake was MONSTROUS-and bow wake (outside wake) quite short.Lost cajones at top of stern wake,and dropped throttle before the drive cleared the water.Donzi "tripped" and began to drop bow on ascent.At the top of the arc, my grandson and I were looking WAY down on the top of the Bertrams flybridge,Donzi nose still down as we crested.My first thought....."You fly, you die!" Absolutely sure we were about to stuff. Just before we touched down (felt like 20 minutes),that wonderful Donziboat settled it's tail and performed the most beautiful landing (outside the bow wake!!)and power-out one could imagine.Still chills my blood to recount the story.The Bertram skipper was watching-so we simply acted like it was just a normal maneuver and drove casually away.Went out of his sight into the next bay, and stopped to wash my knickers out.Grandson too.He understands physics, and knew how lucky we were too. I have a foot throttle, and my leg would NOT push it for having the shakes so bad. Waited ten, then firewalled it for the run back home. Lesson learned- NEVER sneak a big Bertram!! :shocking: :yes:

[mattyboy]

this guy must be hard on impellors ;) :tongue: :eek: :rlol:
fly baby fly

Matty

[cigarette30]

Mattyboy,

That's one impressive fly ...... any details ? I came close to that in an X-18, 20 years ago, have since lost my "stones". The landing came very close to throwing me out. Please advise.

[mattyboy]

I dunno just hang on??? cig 30 I'm not sure?? why ask me I don't fly like that I'm scared of hieghts:rlol: my boat is red it's the yellow ones that fly ???? ;)

Matty
it's not the fall, it's the sudden stop that get's ya!!

[tamburello]

By the registration numbers I'd say that's just another member of the Michigan "air force" getting some flight time. I haven't gotten air like that since I let my brother drive. :beer:

- Jeff

[integra]

I'm very interested in this subject, since my new 26 Zx (that's arriving in few days) is the first fast boat I have ever had...

so, the only advice is when I'm "on air" to pull my throttle completely??

anything else?

Ciao FEDE

[cigarette30]

Integra,

No, the ideal world would be to re-enter the water at the r.m.p. you left, Ie: that way the prop/drive would not suffer the shock. To much, "overrev", to little, "impact", this is not easy, but the closer you get the better, minimize the chance of damage to the drive, and keeping the bow up. Its something you kind of "learn" or 'feel" with time.

[integra]

ok thanx!

It will be difficult first time, but then I hope I'll be able to do so... :idea:

[Hanker]

I can attest that the 22 classic is a very good submarine too. :rolleyes:

Had my family out in government cut, and came up on a sportfish-bow high. I have no idea how big the wake was, but it was pretty big. Anyhow, as I was headin up the wake, I chickened out and hanked back the trottle. Next thing we saw was a wall of green. :eek!:

My wife was not amused at first, the cockpit drained pretty quickly, and we ended up laughing our heads off.

Knowing me, I'll end up going to the other extreme :shocking: before I get it right.

Damn, sounds kinda like life - ya just gotta go for it!