Cats - My first time in the rough - what was that?
03-08-2002, 09:58 AM
#31
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To measure the Center of Moment (which is what you mean when you visualize at what point form the bow or the stern could the boat be balanced by an upward force equal to the weight of the boat) is easy if you have access to a travel lift and four scales. At that point it is simply a moment calculation. This is VERY helpful when rigging...not much you can do about it when the boat is completed except know where to put the weight of anything you add.
Center of Gravity is the point where for calculation purposes, the weight of the boat could be considered to be located. It is near the Center of Moment and off of the boat's running surface upward some feet.
If anyone would like the Excel C of M calculator i did for Lake X i would be happy to email it to you. It is sef explanatory.
Ted
Center of Gravity is the point where for calculation purposes, the weight of the boat could be considered to be located. It is near the Center of Moment and off of the boat's running surface upward some feet.
If anyone would like the Excel C of M calculator i did for Lake X i would be happy to email it to you. It is sef explanatory.
Ted
03-08-2002, 10:32 AM
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Hey UT,
Lot's of recomendations here, and none bad, especially the be safe, first and foremost!! Anyway I spent 5 years in a 26 cat, but twin o/b's and still take it out a few times a summer. My first impression was you were going too slow for proper ride, and not enough lift on the hull. The conditions on Lake st clair are identical to havasu's, usually boat chop, lots of confused boat wake chop, and occasional 5-6 footers. I always found my hull to be a bad ride in anything over 1' till 75 then smoothed out and rode really flat and skipped the tops, and always saw better top end in rougher water. Trim always neutral in chop, and a little positive in glass just for fun. You are on the right track, and having this forum to ask questions is something I wish I had when I learned to drive my cat, but I wasnt so lucky. It's alot smarter than how I did it. Take it out alone, on a rough day, and see how it performs at speed in the rough. I've always found straight line to be safe at speed in rough to a point, but dont attempt any high speed turns in the rough. I think faster in the slop is alot better, and you arent running at blowover speeds, so I wouldnt be too concerned about that, but baby steps, and be carefull, but I think it was all just a issue of not enough speed, but then again, I wouldnt want to scare the passengers either.
Lot's of recomendations here, and none bad, especially the be safe, first and foremost!! Anyway I spent 5 years in a 26 cat, but twin o/b's and still take it out a few times a summer. My first impression was you were going too slow for proper ride, and not enough lift on the hull. The conditions on Lake st clair are identical to havasu's, usually boat chop, lots of confused boat wake chop, and occasional 5-6 footers. I always found my hull to be a bad ride in anything over 1' till 75 then smoothed out and rode really flat and skipped the tops, and always saw better top end in rougher water. Trim always neutral in chop, and a little positive in glass just for fun. You are on the right track, and having this forum to ask questions is something I wish I had when I learned to drive my cat, but I wasnt so lucky. It's alot smarter than how I did it. Take it out alone, on a rough day, and see how it performs at speed in the rough. I've always found straight line to be safe at speed in rough to a point, but dont attempt any high speed turns in the rough. I think faster in the slop is alot better, and you arent running at blowover speeds, so I wouldnt be too concerned about that, but baby steps, and be carefull, but I think it was all just a issue of not enough speed, but then again, I wouldnt want to scare the passengers either.
Last edited by Advantage_Rob; 03-08-2002 at 10:34 AM.
03-08-2002, 10:59 AM
#33
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Advantage_Rob - Thanks so much - great post! I will defiantly take it out by myself and test in the rough - hope we get some this week (never thought I would hear myself say that). Baby steps for sure! What was the ride like at 75 mph on top, is it rough? Will I scare my wife? I'll defiantly work on that neutral trim.
03-08-2002, 11:29 AM
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On my boat it really smoothed out, alot. it went from up and down, bow, to flat and more of a side to side slight skip, just skimming the top of the waves feeling. Keep in mind, My hull is ALOT different than yours, I have a deep tunnel, and no pod, and outboards, which are alot lighter, and a lightweight layup, and no cabin. Totally different boats in every way, and you have the front bow rider, so there's weight up there that I dont know how it would effect the ride, but you'll learn your boat in time just like I did. I dont like to run over 100 too much, it's a handfull, and I'm not a stupid 20 year old like I was when I got this boat, now I think first, well sometimes anyway, as I'm sure you do, but in the waves at higher speeds on my cat were really hard to explain the rush you experience, you'd be on top of 2-3's hauling ass skimming the tops, and you would see a bigger wave, and be like, ohhh, in anticipation of something, and then it was 200 feet behind you and nothing changed or felt any different, it was just behind you, and forward is where your concentration is. I give a ton of credit to the guys that race, there's enough going on at high speeds to watch for, let alone following the course, and watching for other boats all trying to beat you to the next turn. Check my home page, there's a pic of tmy cat from the front, you can see the tunnel depth.
P.S. I was a bit worried about saying, it was scary, go faster, but it holds true, to a point, learn the boat slowly, but learn it well, and never think you know how it's going to react, I've had some moments, and all from going too fast. I'm was waithing for someone to say "What, are you crazy to say that, but someone probably will still. There is a great wealth of knowledge here, and alot to be learned by everyone. lets see what I stirred up.
P.S. I was a bit worried about saying, it was scary, go faster, but it holds true, to a point, learn the boat slowly, but learn it well, and never think you know how it's going to react, I've had some moments, and all from going too fast. I'm was waithing for someone to say "What, are you crazy to say that, but someone probably will still. There is a great wealth of knowledge here, and alot to be learned by everyone. lets see what I stirred up.
03-08-2002, 11:36 AM
#35
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Uncle Toys,
Were you talking about last weekend in Havasu. I put my boat in last Saturday when the winds were high. The swells on the lake were definitely bigger than 2 ft. I thought is was more like 4'. With the wind chop, it's very hard to read the water. I only saw 5 boats on the water that day, all in the channel. Look for me next time your out - White 34' Magic w/ blue and yellow graphics.
Were you talking about last weekend in Havasu. I put my boat in last Saturday when the winds were high. The swells on the lake were definitely bigger than 2 ft. I thought is was more like 4'. With the wind chop, it's very hard to read the water. I only saw 5 boats on the water that day, all in the channel. Look for me next time your out - White 34' Magic w/ blue and yellow graphics.
03-08-2002, 11:44 AM
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Uncle Toys,
I have run several times with four people in the boat in 1-2' Havasu chop at 90 plus mph. I agree with Advatage Rob, If you keep the boat packing air you can stay on top of it and it is a fairly smooth ride. As far as 5-6' chop at Havasu, I saw it that big one time. We were coming from the sandbar and hit the open lake and it was nasty. I tryed to stay in the throttle but we were getting beat up bad. That same day a 26' cat sunk at Windsor trying to pull the boat out. That is why I launch at the Marina which is protected. Good luck.
I have run several times with four people in the boat in 1-2' Havasu chop at 90 plus mph. I agree with Advatage Rob, If you keep the boat packing air you can stay on top of it and it is a fairly smooth ride. As far as 5-6' chop at Havasu, I saw it that big one time. We were coming from the sandbar and hit the open lake and it was nasty. I tryed to stay in the throttle but we were getting beat up bad. That same day a 26' cat sunk at Windsor trying to pull the boat out. That is why I launch at the Marina which is protected. Good luck.
03-08-2002, 12:35 PM
#37
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UT before taking your next ride mark the trim indicators with nail polish on the glass face so you know exactly were everything is even with the bottom. Get a long straight edge and while it's on the trailer make everything nice an even and then mark the glass. You may find that your indicator lines need to be adjusted as well so everything lines up. If you don't know where your drives and tabs are then you don't know what your starting with.
03-08-2002, 01:05 PM
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Advantage_Rob - I hear what your saying in your p.s. This ride I'm talking about actually happened Monday Feb 25th. I've just been too chicken to post it until recently. I guess the trick is we need to be willing to look silly in the short run to pick up knowledge for the long run.
Dytmagic - Did you post pictures of your boat in the member thread? Will keep an eye open for you in the channel.
HavasuCat - That day you hit 5-6'ers, was that last August? Around the middle of last August my wife and son were coming back from Sandbar on the waverunners. They said they were headed home because it was blowing up in the south. At the delta (mouth of the lake) my son said they had to work through 6'ers. Considering he surfs, I thought he might have been rather accurtate. But jeez, I always wondered about that. My neighbor was bringing the little kids back in his 28' Nordic and he said he got his ass kicked.
Dytmagic - Did you post pictures of your boat in the member thread? Will keep an eye open for you in the channel.
HavasuCat - That day you hit 5-6'ers, was that last August? Around the middle of last August my wife and son were coming back from Sandbar on the waverunners. They said they were headed home because it was blowing up in the south. At the delta (mouth of the lake) my son said they had to work through 6'ers. Considering he surfs, I thought he might have been rather accurtate. But jeez, I always wondered about that. My neighbor was bringing the little kids back in his 28' Nordic and he said he got his ass kicked.
03-08-2002, 02:53 PM
#39
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UT.... having to trim up for max speed doesn't necessarily mean that you have to carry the bow with horsepower, more often then not it means that your drives are too low and trimming up reduces the water flowing to the prop, thereby reducing drag , increasing RPM, raising HP and increasing speed. A lot of boats in this condition simply raise their rooster tails without raising bow height. Don't take this matter lightly as the condition you encountered could lead to a full blown stuff at speed. Stuffs(without canopies) tend to be fatal over 100 mph...... very "cleansing" (all orifices violated) between 70-100..... and just very wet experiences below 70.... but I stuffed an Allison once at 65 mph and sent a co-driver under the bailing well....with his seat still stuck to his butt.
As to wave height...... A 1 foot chop measures 12 inches from mid wave(normal calm water level point) to top and 12 inches from mid wave (ditto) to trough...... or a 2 foot overall wave height. A two foot chop features four foot waves etc..... Your basic lake (and I raced on Havasu years ago) maxes out at about a two foot chop (4 foot waves)......with the exception of big cruiser wakes. That's a lot for a 26 footer to handle.....Lake St Clair is bigger... a lot bigger...... and can show 5 foot seas (10 foot waves) during storms and high winds.
Most offshore races occur in flat and 1-2 foot seas today (inshore) and 3-4's(offshore). Storm courses are usually employed when seas are over that.
T2x
PS: Otto....... Nah! I definitely limited it to Skaters....as in "Buy a Skater" ... I wouldn't own anything else...unless one of my previous companies built it of course......
As to wave height...... A 1 foot chop measures 12 inches from mid wave(normal calm water level point) to top and 12 inches from mid wave (ditto) to trough...... or a 2 foot overall wave height. A two foot chop features four foot waves etc..... Your basic lake (and I raced on Havasu years ago) maxes out at about a two foot chop (4 foot waves)......with the exception of big cruiser wakes. That's a lot for a 26 footer to handle.....Lake St Clair is bigger... a lot bigger...... and can show 5 foot seas (10 foot waves) during storms and high winds.
Most offshore races occur in flat and 1-2 foot seas today (inshore) and 3-4's(offshore). Storm courses are usually employed when seas are over that.
T2x
PS: Otto....... Nah! I definitely limited it to Skaters....as in "Buy a Skater" ... I wouldn't own anything else...unless one of my previous companies built it of course......
Last edited by T2x; 03-08-2002 at 02:57 PM.
03-08-2002, 03:24 PM
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SO T2x,
Your opinion seems to hold alot of weight, but you have no opinions on the speed being too low for proper lift? You generalize about the danger involved with a stuff increasing with speed, which we all agree upon, but in my cat 65 is a really bad speed to go unless it's flat. I dont know anything about eliminator cat's other than they look great, and what I watched on speedvision w/ the siebold 36.
St clair does occasionally get horrible, but generally is less than 3' total wave hieght, very similar conditions to what I've seen in havasu in my 3 visits.
Your opinion seems to hold alot of weight, but you have no opinions on the speed being too low for proper lift? You generalize about the danger involved with a stuff increasing with speed, which we all agree upon, but in my cat 65 is a really bad speed to go unless it's flat. I dont know anything about eliminator cat's other than they look great, and what I watched on speedvision w/ the siebold 36.
St clair does occasionally get horrible, but generally is less than 3' total wave hieght, very similar conditions to what I've seen in havasu in my 3 visits.
