Design Experts, Rough Water Question.
07-30-2008, 01:27 PM
#21
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Great post!
I have wondered myself the reason behind the size
of the sponsons going forward.
I realize this is on the bigger end of the scale But take notice on how tall (Deep) the sponsons get towards the nose.
Towards the transom it is approx 3.5 feet high to rubrail.
When measuring the front depth it is almost 5.5 feet high
to rubrail With a quick taper to the bow points.
Its hard getting it all in the camera
But its odvious that it is built huge towards the bow.
I have wondered myself the reason behind the size
of the sponsons going forward.
I realize this is on the bigger end of the scale But take notice on how tall (Deep) the sponsons get towards the nose.
Towards the transom it is approx 3.5 feet high to rubrail.
When measuring the front depth it is almost 5.5 feet high
to rubrail With a quick taper to the bow points.
Its hard getting it all in the camera
But its odvious that it is built huge towards the bow.
07-30-2008, 01:36 PM
#22
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I know any excuse to post pictures of my boat!
Seriously you can really see how big they are.
Seriously you can really see how big they are.
07-30-2008, 02:12 PM
#23
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T2x
07-30-2008, 03:50 PM
#26
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Seriously, I am very big on the concept of scale speed....
i.e. a 16 foot tunnel boat at 130mph is equivalent to a 32 cat at 260 mph...or a 48' cat at 390 mph. if all things are equal....(and they never are). While this may not be quite as direct a scale up....it is not far off...and explains why it still takes a lot more talent and stones to drive a Champ boat on a tight course in traffic than to make a one way speed run in a turbine powered cat (with all due respect to the guys who do that as well).
A 40 foot "wing" with proper modern power will do two things:
1. Go very fast.........
2. Attain these amazing speeds with less power than a traditional Cat or even the "Cat Killer"
.
The issue of course, as it has always been, is the rough water handling and turning capabilities of the design. While Wings were no slouches in the mixed chop they raced in at courses like Lake Havasu, Biscayne Bay/Miami Marine Stadium, etc. They very definitely had a wave height limit and that limit was an absolute. If you scaled the design up to 40 feet or so...that limit would also increase accordingly....but it would still be there..... until and unless certain changes were made in the hydrodynamic design of the sponsons.
That ....my friends is the challenge in a nutshell.... a challenge which I am sure is solvable IMHO.
T2x
i.e. a 16 foot tunnel boat at 130mph is equivalent to a 32 cat at 260 mph...or a 48' cat at 390 mph. if all things are equal....(and they never are). While this may not be quite as direct a scale up....it is not far off...and explains why it still takes a lot more talent and stones to drive a Champ boat on a tight course in traffic than to make a one way speed run in a turbine powered cat (with all due respect to the guys who do that as well).
A 40 foot "wing" with proper modern power will do two things:
1. Go very fast.........
2. Attain these amazing speeds with less power than a traditional Cat or even the "Cat Killer"
.The issue of course, as it has always been, is the rough water handling and turning capabilities of the design. While Wings were no slouches in the mixed chop they raced in at courses like Lake Havasu, Biscayne Bay/Miami Marine Stadium, etc. They very definitely had a wave height limit and that limit was an absolute. If you scaled the design up to 40 feet or so...that limit would also increase accordingly....but it would still be there..... until and unless certain changes were made in the hydrodynamic design of the sponsons.
That ....my friends is the challenge in a nutshell.... a challenge which I am sure is solvable IMHO.
T2x
Last edited by T2x; 07-30-2008 at 03:52 PM.
07-30-2008, 04:23 PM
#27
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Why do you think the European Deep V boats of the early years tended to have a short straight keel area with a shallow long forefoot as opposed to the longer keeled deeper forefoot of the American designs.
Was this trade off of a short footprint strictly to keep the wetted surface down for spee?.And did it work? They stayed with those designs for many years.
And a quick question for Brownie long as we are on the same subject.
I now know that your Nova came from the Donzi 8 metre and I can't remember who you said designed it and if you had any input at the time when the hull was designed for Donzi.I think you had said you were at Donzi at the time
.But anyways here is my question.
Why was that particular design so different from all the other high speed offshore boats of the era with the heavily flared forward topsides and the deep abrupt Forefoot.? Was the hull originally designed for a fishing boat for Donzi and you saw in it a good hull for a rough water offshore boat for the length.I have always admired the Novas and their destinctive looks but i have never rode in one in the rough.How did the hull perform with this different approach to design ?
Was this trade off of a short footprint strictly to keep the wetted surface down for spee?.And did it work? They stayed with those designs for many years.
And a quick question for Brownie long as we are on the same subject.
I now know that your Nova came from the Donzi 8 metre and I can't remember who you said designed it and if you had any input at the time when the hull was designed for Donzi.I think you had said you were at Donzi at the time
.But anyways here is my question.
Why was that particular design so different from all the other high speed offshore boats of the era with the heavily flared forward topsides and the deep abrupt Forefoot.? Was the hull originally designed for a fishing boat for Donzi and you saw in it a good hull for a rough water offshore boat for the length.I have always admired the Novas and their destinctive looks but i have never rode in one in the rough.How did the hull perform with this different approach to design ?
07-30-2008, 04:25 PM
#28
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Seriously, I am very big on the concept of scale speed....
i.e. a 16 foot tunnel boat at 130mph is equivalent to a 32 cat at 260 mph...or a 48' cat at 390 mph. if all things are equal....(and they never are). While this may not be quite as direct a scale up....it is not far off...and explains why it still takes a lot more talent and stones to drive a Champ boat on a tight course in traffic than to make a one way speed run in a turbine powered cat (with all due respect to the guys who do that as well).
A 40 foot "wing" with proper modern power will do two things:
1. Go very fast.........
2. Attain these amazing speeds with less power than a traditional Cat or even the "Cat Killer".
The issue of course, as it has always been, is the rough water handling and turning capabilities of the design. While Wings were no slouches in the mixed chop they raced in at courses like Lake Havasu, Biscayne Bay/Miami Marine Stadium, etc. They very definitely had a wave height limit and that limit was an absolute. If you scaled the design up to 40 feet or so...that limit would also increase accordingly....but it would still be there..... until and unless certain changes were made in the hydrodynamic design of the sponsons.
That ....my friends is the challenge in a nutshell.... a challenge which I am sure is solvable IMHO.
T2x
i.e. a 16 foot tunnel boat at 130mph is equivalent to a 32 cat at 260 mph...or a 48' cat at 390 mph. if all things are equal....(and they never are). While this may not be quite as direct a scale up....it is not far off...and explains why it still takes a lot more talent and stones to drive a Champ boat on a tight course in traffic than to make a one way speed run in a turbine powered cat (with all due respect to the guys who do that as well).
A 40 foot "wing" with proper modern power will do two things:
1. Go very fast.........
2. Attain these amazing speeds with less power than a traditional Cat or even the "Cat Killer"
.The issue of course, as it has always been, is the rough water handling and turning capabilities of the design. While Wings were no slouches in the mixed chop they raced in at courses like Lake Havasu, Biscayne Bay/Miami Marine Stadium, etc. They very definitely had a wave height limit and that limit was an absolute. If you scaled the design up to 40 feet or so...that limit would also increase accordingly....but it would still be there..... until and unless certain changes were made in the hydrodynamic design of the sponsons.
That ....my friends is the challenge in a nutshell.... a challenge which I am sure is solvable IMHO.
T2x
T2x I have some questions....
I believe my 40 has a tunnel width of 58 inches. I think the new widebodys are 66 inches. If wider is better, when is a tunnel too wide? Don't you lose alot of compression?
Second question. Some of the early 90's Skaters have a v towards the back of the tunnel. What does that accomplish??
Thanks,
Erik
07-30-2008, 04:37 PM
#29
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I love these threads...
T2x I have some questions....
I believe my 40 has a tunnel width of 58 inches. I think the new widebodys are 66 inches. If wider is better, when is a tunnel too wide? Don't you lose alot of compression?
Second question. Some of the early 90's Skaters have a v towards the back of the tunnel. What does that accomplish??
Thanks,
Erik
T2x I have some questions....
I believe my 40 has a tunnel width of 58 inches. I think the new widebodys are 66 inches. If wider is better, when is a tunnel too wide? Don't you lose alot of compression?
Second question. Some of the early 90's Skaters have a v towards the back of the tunnel. What does that accomplish??
Thanks,
Erik
Erik:
Compression is a function of tunnel angle fore and aft....not width. Increased width gives increased overall lift.
"Too wide" is a condition that will vary from hull to hull and for a specific application. To me, too wide, is when the width compromises the hull strength and makes the boat overly slippery in turns...... The new Skaters have neither problem it seems.
By the way, my 1968 20' Wing Switzer has a wider tunnel than my 28' Skater....and that is probably where the "new" wide tunnel concept came from.
Vee's in tunnels do a couple of things:
1. provide a natural "wedge" aft to reduce loping
2. In our cats the vee went full length in the tunnels to aid in softening the blow from wave impact in the roughest conditions.
T2x
07-30-2008, 04:40 PM
#30
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Why do you think the European Deep V boats of the early years tended to have a short straight keel area with a shallow long forefoot as opposed to the longer keeled deeper forefoot of the American designs.
Was this trade off of a short footprint strictly to keep the wetted surface down for spee?.And did it work? They stayed with those designs for many years.
And a quick question for Brownie long as we are on the same subject.
I now know that your Nova came from the Donzi 8 metre and I can't remember who you said designed it and if you had any input at the time when the hull was designed for Donzi.I think you had said you were at Donzi at the time
.But anyways here is my question.
Why was that particular design so different from all the other high speed offshore boats of the era with the heavily flared forward topsides and the deep abrupt Forefoot.? Was the hull originally designed for a fishing boat for Donzi and you saw in it a good hull for a rough water offshore boat for the length.I have always admired the Novas and their destinctive looks but i have never rode in one in the rough.How did the hull perform with this different approach to design ?
Was this trade off of a short footprint strictly to keep the wetted surface down for spee?.And did it work? They stayed with those designs for many years.
And a quick question for Brownie long as we are on the same subject.
I now know that your Nova came from the Donzi 8 metre and I can't remember who you said designed it and if you had any input at the time when the hull was designed for Donzi.I think you had said you were at Donzi at the time
.But anyways here is my question.
Why was that particular design so different from all the other high speed offshore boats of the era with the heavily flared forward topsides and the deep abrupt Forefoot.? Was the hull originally designed for a fishing boat for Donzi and you saw in it a good hull for a rough water offshore boat for the length.I have always admired the Novas and their destinctive looks but i have never rode in one in the rough.How did the hull perform with this different approach to design ?
