Hull Taper

A general, non-powerplant specific, discussion on airboat technology, ie., hulls, rigging, polymer, etc..
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Seven3
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Hull Taper

Post by Seven3 » Thu Oct 03, 2019 10:23 pm

Just curious about the science behind figuring what taper to bend the sheets of a riveted hull at (stern to bow taper). You look at some of the old Thurmans and they have a lot of taper making the bow deeper. But the later Thurmans, and the newer Benny Webb’s have less taper. The Don Davis’ and Wardaddy’s seem to have a lot less taper. Is it all just about getting the boat to jump up on plane quicker?

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John Fenner
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Re: Hull Taper

Post by John Fenner » Mon Oct 07, 2019 8:14 am

Yes, I build mine with 5" of taper per side they tend to be on plane with a throttle blip, wider is better.
I never finish anyth,,,.

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John Fenner
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Re: Hull Taper

Post by John Fenner » Mon Oct 07, 2019 8:21 am

The older thurman hulls had heavy taper to drop the nose farther, those boats were built specifically to have a proper sized drawer on each side to haul a certain size package(s) that were extracted from certain areas back in the good ole boy days, wink wink.
I never finish anyth,,,.

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digginfool
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Re: Hull Taper

Post by digginfool » Mon Oct 07, 2019 4:22 pm

John Fenner wrote:
Mon Oct 07, 2019 8:21 am
The older thurman hulls had heavy taper to drop the nose farther, those boats were built specifically to have a proper sized drawer on each side to haul a certain size package(s) that were extracted from certain areas back in the good ole boy days, wink wink.


:lol: :lol: :lol: :lol: This guy.
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Gary S
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Re: Hull Taper

Post by Gary S » Tue Oct 08, 2019 8:00 am

Chewing tobacco?

Seven3
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Re: Hull Taper

Post by Seven3 » Tue Oct 08, 2019 3:34 pm

Diggin you have a set of those boxes in yours...better make sure there’s no residue left in them LOL. My new one has a set as well.
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digginfool
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Re: Hull Taper

Post by digginfool » Wed Oct 09, 2019 7:37 am

Seven3 wrote:
Tue Oct 08, 2019 3:34 pm
Diggin you have a set of those boxes in yours...better make sure there’s no residue left in them LOL. My new one has a set as well.
If there's any residue in there, I'll have to blame the previous owner. 8) :lol: :lol:
“When plunder becomes a way of life for a group of men living together in society, they create for themselves in the course of time a legal system that authorizes it and a moral code that glorifies it” - Bastiat

gary
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Re: Hull Taper

Post by gary » Wed Feb 12, 2020 9:24 am

John Fenner wrote:
Mon Oct 07, 2019 8:14 am
Yes, I build mine with 5" of taper per side they tend to be on plane with a throttle blip, wider is better.
Could you explain further, I'm not understanding what your talking about?

Thanks, Gary

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John Fenner
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Re: Hull Taper

Post by John Fenner » Wed Feb 12, 2020 9:31 am

When I have the sides bent, say for a 6'8" x 12' the rear will be bent at 8" the front will be at 13",that puts a 5" taper into the hull per side.
I never finish anyth,,,.

gary
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Re: Hull Taper

Post by gary » Wed Feb 12, 2020 7:27 pm

John Fenner wrote:
Wed Feb 12, 2020 9:31 am
When I have the sides bent, say for a 6'8" x 12' the rear will be bent at 8" the front will be at 13",that puts a 5" taper into the hull per side.
Gotcha, Thanks, so it's like a slope from bow to stern? Not to go-jack sevens thread, how do you determine the kick up from the side to be bottom of boat?

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Re: Hull Taper

Post by gary » Wed Feb 12, 2020 7:39 pm

Something going on with my internet. Sorry for multiple repeat posts

Seven3
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Re: Hull Taper

Post by Seven3 » Wed Feb 12, 2020 8:46 pm

Gary for an illustration, here are two almost identical hulls built by the same builder. Both are 14x7. The first boat was built with 8” of taper (10” at the rear, 18” at the 12’ mark). The second boat was built with 9” of taper (10” at the rear, 19” at the 12’ mark). The hull with more taper (bottom) is 2” narrower at the bow, and you can see it’s a little deeper in the bow.
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gary
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Re: Hull Taper

Post by gary » Wed Feb 12, 2020 9:08 pm

Seven3 wrote:
Wed Feb 12, 2020 8:46 pm
Gary for an illustration, here are two almost identical hulls built by the same builder. Both are 14x7. The first boat was built with 8” of taper (10” at the rear, 18” at the 12’ mark). The second boat was built with 9” of taper (10” at the rear, 19” at the 12’ mark). The hull with more taper (bottom) is 2” narrower at the bow, and you can see it’s a little deeper in the bow.
Thanks Seven! Appreciate the illustration. Have any info on the kickup?

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John Fenner
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Re: Hull Taper

Post by John Fenner » Fri Feb 14, 2020 10:03 am

I usually go to 2" on say a 6 cylinder sled or car engine powered hull, 4 cylinder I will kick it to about 2-3/4 but not drastic, more so at the stringers.
I never finish anyth,,,.

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