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I Surrender! Time to Re-rig

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Old 10-10-2007, 04:02 PM
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Default I Surrender! Time to Re-rig

Four years ago I undertook a project that would give us the ideal boat for our needs. My list was long: rough water capable with power, family watersports, carry a lot of passengers with lots of cockpit room. To satisfy the roomy cockpit requirement I selected the Pulsedrive - which required mounting the engines low in the bilge. The engines sit under the rear couch.

I endured fraudulently new engines ($$$), a botched rigging job ($$$) and a host of gremlins. This boating season has been our best so far, thanks to the efforts of Eddie Young.

I have come to the conclusion that the Pulsedrive is just not right for the Envision hull. The hull's inner strakes run all the way back to the transom, giving the boat a ton of stern lift at higher speeds. At speeds over 70 mph it's a handful. At speeds over 80 mph it's scary.

There are a few things I am going to miss: awesome docking manners, on plane at 14 mph, amazing wake for watersports, efficient crusing at 50 mph, and no drive breakage due to flying. The Pulsedrive would work very well in a vee hull needing stern lift.

Off into the sunset she goes.......
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Old 10-10-2007, 05:21 PM
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Do you spin the props in or out?
Does the bottom have a rocker in it?
What prop are you running?

I would look into shortening the stakes, B/P bottm and some prop work. Alot less money than re-rigging. Your package sounds pretty good. Alittle more work and you may be there.
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Old 10-10-2007, 05:26 PM
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What drives are you moving to?
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Old 10-10-2007, 05:55 PM
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Originally Posted by CIG3 View Post
Do you spin the props in or out?
Does the bottom have a rocker in it?
What prop are you running?

I would look into shortening the stakes, B/P bottm and some prop work. Alot less money than re-rigging. Your package sounds pretty good. Alittle more work and you may be there.
I've tried both. Spinning in helps the bow at mid range, but the advantage is gone at speeds over 60 mph.

No rocker in the hull - I wish there was some

Merc 5 blade cleavers w/ rounded tips by Bblades

I've spent too much money on fixing the next thing that might help. Outdrives will allow me to trim the props and leverage the bow.
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Old 10-10-2007, 05:59 PM
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What drives are you moving to?
See my post in the technical section. I'm seeking opinions.
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Old 10-10-2007, 09:11 PM
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I would thing you are pushign the hull beyond what it is intended to do, not that most of us on here don't do the same. You have to be one of the few if not the only 80+ Envision out there. I think you should try some hull work too before scrapping the setup you have now, that rooster tail is just to cool to give up on.
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Old 10-10-2007, 09:50 PM
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I'm definitely pushing the hull design, however, there is someone at LOTO running a single 29 with insame power well over 100 mph using an extension box and beefy drive. The 29 hull is very similar to the 32.

Working the hull may fix my top end problems, and it may not. It may also kill my low speed performance which I need. My hull and bilge configuration prevents me from getting even close to neutral trim angle. Even if I reduce stern lift by trimming the strakes I'll still have the big diameter 5 blade props pushing up on the stern.

With outdrives I should be able to keep low speed functionality and have a better chance of curing my high speed ailments by leveraging the bow with positive trim. She's seen 85 mph with plenty of stick left and the bow pushing down. I'd like to she what she can safely achieve.

If someone has a miracle cure please let me know!
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Old 10-10-2007, 10:28 PM
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I have a 30' twin BBC 24 degree vee that eventually became perfectly stable at 100+MPH. In my experience, speed and stability came only after we got the length of the inter strakes right. The good news for your boat is that your strakes are too long: it is much easier (less $) to shorten vs lengthen.
A good place to start is to make the inter strakes somewhere around 12" behind the CG; this should be close. My CG was at 91". Maybe shorten them in three increments if you want to be conservative.
As to props, in my case the 5-blade props (Herring) added about 2 MPH in top speed but it was scarry loose at WOT. After testing turning them in and out at 105-107 MPH they never went back on the boat. Having the transom planted at high speed in a 30' something boat is important...based on the size of my balls.
My ideal prop shaft height ended up between .75 - 1.5" below the bottom on boxes. The speed was identical at both X's. I spent $25-50K the figure this out...probably a lot more but this is all I will admit to
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Old 10-10-2007, 10:32 PM
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You have to be one of the few if not the only 80+ Envision out there. .

I know one with a single 1250 in it, I hear it runs about a buck.
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Old 10-10-2007, 10:41 PM
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Frequency,
By the way, I don't know anything about an Envision hull. If it has a ventilated bottom, my straight vee experience likely does not apply.
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