Thad Allen's Apache + The Birth of the Cheetah Cat
08-01-2013, 08:42 PM
#643
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Jeez Steve, I remember thinking, why would anyone want to build catamarans? They are such a pain compared to V bottoms.
After a 19' cat, then the 22' cat we made a 27' cat. I guess I am taking it one step at a time :-) Pun intended as you may see if you look closely.
Its not 1100 lbs like the Cheetah., but its not bad.
After a 19' cat, then the 22' cat we made a 27' cat. I guess I am taking it one step at a time :-) Pun intended as you may see if you look closely.
Its not 1100 lbs like the Cheetah., but its not bad.
I think I've seen that Cat before..LOL
08-02-2013, 09:07 AM
#644
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We found that for the speed we go 55-60 mph, the longer waterline, sharper entry and deeper fore foot is what it is all about for soft ride. The 27 you see feel like sitting on your living room couch in waves. Video taken in mild seas going through Oregon Inlet for a first sea trial.
Many years ago when Harry Schoell was designing the early V bottoms he had a re circulating water test tank that he could hold the model in the water flow and feel by hand what changes to the model affected. One was bow rake which affected bow steer at high speed. He would take the model over to the band saw and saw more bow rake bit by bit until it felt right. I forget which Deep V he did like that first, but it was a long time ago and was copied widely.
Our next cat is anticipated to run in the 70-80's and I hate to give up the ride but want to be safe at speed too. The most bow rake on any boat I have ever seen is the 116' "Gentry Eagle" and Brownie told me its the hardest riding boat he had ever been on. It did a big hook at 75 mph coming off a wave when one engine over sped and the computer shut it down so there are always a lot of factors. There must be a compromise. I always thought you were a Rakish kind of Guy, Any thoughts on a bow angle we should be looking at?
Many years ago when Harry Schoell was designing the early V bottoms he had a re circulating water test tank that he could hold the model in the water flow and feel by hand what changes to the model affected. One was bow rake which affected bow steer at high speed. He would take the model over to the band saw and saw more bow rake bit by bit until it felt right. I forget which Deep V he did like that first, but it was a long time ago and was copied widely.
Our next cat is anticipated to run in the 70-80's and I hate to give up the ride but want to be safe at speed too. The most bow rake on any boat I have ever seen is the 116' "Gentry Eagle" and Brownie told me its the hardest riding boat he had ever been on. It did a big hook at 75 mph coming off a wave when one engine over sped and the computer shut it down so there are always a lot of factors. There must be a compromise. I always thought you were a Rakish kind of Guy, Any thoughts on a bow angle we should be looking at?
08-02-2013, 02:39 PM
#645
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We found that for the speed we go 55-60 mph, the longer waterline, sharper entry and deeper fore foot is what it is all about for soft ride. The 27 you see feel like sitting on your living room couch in waves. Video taken in mild seas going through Oregon Inlet for a first sea trial.
Many years ago when Harry Schoell was designing the early V bottoms he had a re circulating water test tank that he could hold the model in the water flow and feel by hand what changes to the model affected. One was bow rake which affected bow steer at high speed. He would take the model over to the band saw and saw more bow rake bit by bit until it felt right. I forget which Deep V he did like that first, but it was a long time ago and was copied widely.
Our next cat is anticipated to run in the 70-80's and I hate to give up the ride but want to be safe at speed too. The most bow rake on any boat I have ever seen is the 116' "Gentry Eagle" and Brownie told me its the hardest riding boat he had ever been on. It did a big hook at 75 mph coming off a wave when one engine over sped and the computer shut it down so there are always a lot of factors. There must be a compromise. I always thought you were a Rakish kind of Guy, Any thoughts on a bow angle we should be looking at?
Many years ago when Harry Schoell was designing the early V bottoms he had a re circulating water test tank that he could hold the model in the water flow and feel by hand what changes to the model affected. One was bow rake which affected bow steer at high speed. He would take the model over to the band saw and saw more bow rake bit by bit until it felt right. I forget which Deep V he did like that first, but it was a long time ago and was copied widely.
Our next cat is anticipated to run in the 70-80's and I hate to give up the ride but want to be safe at speed too. The most bow rake on any boat I have ever seen is the 116' "Gentry Eagle" and Brownie told me its the hardest riding boat he had ever been on. It did a big hook at 75 mph coming off a wave when one engine over sped and the computer shut it down so there are always a lot of factors. There must be a compromise. I always thought you were a Rakish kind of Guy, Any thoughts on a bow angle we should be looking at?
Jim , Nice reply , designing a Cat that has to work WELL from Boat Mode to high speed is tricky , Depending how "critical" one is , I use a very fine entry btw Like the looks of your boats and will dig up some pictures , Right now , I am Designing a Small Cat 19' for 2 of my sons they like the boat business ..
08-02-2013, 03:01 PM
#646
Steve, first off Great thread! I really appreciate you sharing your expertise with the OSO membership, it's both enjoyable & educational. Okay, on to my question. The addition of steps to the 41 or 47 Apache design. Bad idea/great idea? How much design work is needed? What performance benefits could be expected? Speed/handling fuel economy etc.
Thanks
Ed
Thanks
Ed
Last edited by Comanche3Six; 08-02-2013 at 04:54 PM.
08-02-2013, 04:24 PM
#647
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08-02-2013, 04:52 PM
#648
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Ed , the game is about "Apparent" surface area and imposing a running attitude , Imagine we cut the boat in 3 or4 pieces and reassemble the thing with the rear sections angled down 2-3 Degrees to the aft , the whole thing is about Friction and trying to lose some as the boat gains speed the running surface goes further to the transom , We have higher pressure in a smaller area of friction is the result , the attitude ? some boats like 3 degrees angle of attack , again up to the cleverness of the designer in shedding the affinity of that glob of water wanting to Cling to the boat hull , Speed , Fuel economy , and longevity of everything in the propulsion system will benefit Greatly .
08-02-2013, 04:58 PM
#649
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We will build one , then it will be shown and fished , small Light fast and small power , I will have them show it to you .
08-02-2013, 05:27 PM
#650
Ed , the game is about "Apparent" surface area and imposing a running attitude , Imagine we cut the boat in 3 or4 pieces and reassemble the thing with the rear sections angled down 2-3 Degrees to the aft , the whole thing is about Friction and trying to lose some as the boat gains speed the running surface goes further to the transom , We have higher pressure in a smaller area of friction is the result , the attitude ? some boats like 3 degrees angle of attack , again up to the cleverness of the designer in shedding the affinity of that glob of water wanting to Cling to the boat hull , Speed , Fuel economy , and longevity of everything in the propulsion system will benefit Greatly .
I actually understood a little bit of that! LOL!
