Offshore Tunnel Boats aka "Cats"
#11
Registered
Thread Starter
Join Date: Mar 2010
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
There is more details, but the evolution has been outstanding.
#12
Neno the mind boggler
VIP Member
I believe this boat was built by Seebold around 1980 and was rigged at Lake X with Cosworths. It was very diffucult to get on plane. Later I think it was repowered to Keith Blacks, it was fast but a little hairy and not dependable. Then it was rigged with V-8's and driven by Buck Thorton. I heard the last time it was seen was at Kramer's place "Apache". Reports were the boat was very well built.
__________________
Throttles- Cleveland Construction 377 Talon
08 OPA Class 1 National Champion
08 Class 1 Geico Triple Crown Champion
08 OPA High Points Champion
10 OPA Class 1 National Champion ( happy now Ed! )
Throttles- Cleveland Construction 377 Talon
08 OPA Class 1 National Champion
08 Class 1 Geico Triple Crown Champion
08 OPA High Points Champion
10 OPA Class 1 National Champion ( happy now Ed! )
#13
Allergic to Nonsense
Platinum Member
Join Date: Aug 2001
Location: Granite Quarry, NC
Posts: 5,011
Likes: 0
Received 17 Likes
on
17 Posts
A tunnel boat is a catamaran with "assymetrical" sponsons.
The older designs (and one new one, Deep Vee Cats) have/had symmetrical sponsons.
T2x
#14
Registered
Thread Starter
Join Date: Mar 2010
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
Don't you think the concept has changed? The Cats today are more like scaled up OPC boats. What do you think?
#15
Allergic to Nonsense
Platinum Member
Join Date: Aug 2001
Location: Granite Quarry, NC
Posts: 5,011
Likes: 0
Received 17 Likes
on
17 Posts
Todays Offshore cats are not very different from the early designs with two exceptions.
- They are MUCH lighter due to newer materials
- The tunnels tend to be wider
At the end of the day the increase in power and prop technology is the main reason the current cats are going so fast. When we built the original Shadow cat we felt like 115-120 was the absolute maximum speed potential. There's a guy in Louisiana I believe who has brought his up to over 150.... proving it's all about the power and propulsion.......
There's a lot of mumbo jumbo around the "design skills" of some of our current cat builders. Give me a builder with the most years of experience....because in high performance boats .....the top guys in the field learn a lot more from trial and error....then from computers.
T2x
#16
Registered
Thread Starter
Join Date: Mar 2010
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
There is nothing new under the sun. The original Jones and Cougar hulls back in the 70's were, in fact, scaled up from their earlier OPC designs.....and Jones' OPC designs were merely his cabover hydros with the sponsons lengthened to the stern. I raced a 1977 Molinari with one sponson altered forward to make left turns. it put me in the infield 2 times in the first and only race I tried it in. Later we put it back to its original form. I am not sure about any offshore cats with different sponsons , but I have seen offset cockpits and unequal sponsons in Unlimited hydros.....
Todays Offshore cats are not very different from the early designs with two exceptions.
At the end of the day the increase in power and prop technology is the main reason the current cats are going so fast. When we built the original Shadow cat we felt like 115-120 was the absolute maximum speed potential. There's a guy in Louisiana I believe who has brought his up to over 150.... proving it's all about the power and propulsion.......
There's a lot of mumbo jumbo around the "design skills" of some of our current cat builders. Give me a builder with the most years of experience....because in high performance boats .....the top guys in the field learn a lot more from trial and error....then from computers.
T2x
Todays Offshore cats are not very different from the early designs with two exceptions.
- They are MUCH lighter due to newer materials
- The tunnels tend to be wider
At the end of the day the increase in power and prop technology is the main reason the current cats are going so fast. When we built the original Shadow cat we felt like 115-120 was the absolute maximum speed potential. There's a guy in Louisiana I believe who has brought his up to over 150.... proving it's all about the power and propulsion.......
There's a lot of mumbo jumbo around the "design skills" of some of our current cat builders. Give me a builder with the most years of experience....because in high performance boats .....the top guys in the field learn a lot more from trial and error....then from computers.
T2x
Tunnel hulls are distinguishable from other catamarans by the typical close hull spacing and solid deck in between the hulls.
After much real life testing and at the convention in Trondheim, Norway - 1989, ground effects in contained form became an applied science.
There is more about how Reynolds Numbers fall into this subject, but it's a long science. You are 100% correct, All the years of trial and error proved that it is a science and not art form.
Oldstuff
#17
Gold Member
Gold Member
It is actually a way to quantitatively compare, as a ratio, the two primary forces, inertial and viscous, in a specific flow condition. I remember lots of pages of discussion in my paper on transport phenomenon, regarding laminar flow, boundary layers, transition layers, and turbulence, all correlated to changes in the surfaces, expressed with Reynolds Numbers.
Very dull tedious stuff at the time...who knew...years latter...knowing this stuff makes you understand how we go so fast.
No question, there is allot of science in how we go fast.
Trial and error or science, they both get my vote.
Cool thread!