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I currently own a monohull but I am seriously thinking about switching to a Catamaran.
The question that I have about multihulls is regarding thier speed in choppy waters. When people make referances to a certain speed in 3-4 foot waves are these swells i.e. twenty feet distance between waves or are they the type of waves that beat the life out of you?
I read one post in which the owner of the cat said his boat did 35 knots in 6-8 feet seas, that seems a bit far fetch, or can a cat actually reach those types of speed in those conditions SAFELY
Yeah, they can run as fast as you want in a 3-5 ft sloppy sea. They outperform monohulls when running into almost any sea, but there are tradeoffs. They can be difficult to trim out properly - it often reqires much more fine tuning than a monohull. They also troll sloppily into a headsea. The dreaded snap-roll is also something that takes getting used to. My dad was pitched out of a cat at 40mph due to this. You must also fatcor in the aesthetic issue. We run a 26 ft cat out of Hatteras, NC, and can fish many more days than a monohull much larger
I own a Grady cat with twin 225s. I bought it because it does ride smoother than a monohull.
I fished "the lumps" out of Grand Isle, LA on January 4, 2003 which is about 50 miles offshore. Weather was not great. When I got there I was surrounded by about 30 other cats of various make and size. It looked like a catamaran boat show! I had no idea there were so many of them.
Caught a 120 Yellowfin and eased on in. (that typed alot easier than the actual event.)
35 knots in 6-8 footers. Gimme a break..... No boat is going to run 35 knots in 6-8 footers.I have rifdden on alot of cats. Their best ride is in 1-3 or 2-4. At this wave height, the majority of wave action is slipping beneath their twin hulls.
Sounds like we need to do another mono vs. cat shootout again.
Dont get me wrong, cats are better than many flat bottom hulls (whaler, scout, pursuit, mako) but they are not going to outrun a deepvee (contender, yellowfin, seavee, intrepid, etc).
I run a GB 26 out of San Francisco in the Pacifica ocean. Its often 2-4' waves close spaced with swell 5-9ft. I can run 24-28mph in comfort and usually pass up all of the monos.
Some of the claims obviously get a little far fetched. There's 4 foot seas then there's 4 foot seas but in a proper 6-8 feet sea it's absolute rubbish relevent to the type of vessels discussed here.
Similar the claims regarding deep-vee's, some get a little fanciful at times.
40 mph in 5' seas doesn't sound right to me either.How do you keep the boat in the water.When I run offshore in 3-4' swells at 35,I can't keep my 29' Fountain in the water.It comes off the back side of wave and goes airborn.30 is about as much as I can run unless it's flat,then look out,there I go,"Sea-Ya".
I remember a number of years back, like early 80's, in offshore racing, if the water conditions were rough, the deep V offshore boats would run past the cats, while they couldn't keep up with them in calmer water. I don't know if they've redesigned the cat hulls since then, but that's the way things were, way back when.
i can run 30 to 35 mph in 3 to 4 foot close chop. But you still will have to hold on. my cat performs great at 30mph in almost any sea and will not beat you . Now if it is 7 or 8 foot and u run directly into it then you will run about 15. The deep vee boat can run faster no doubt about it but the contenders i have ridden in will get you wetter and a little harder riding. Really two different animals!!
i thought long and hard about going from my old cat to a 31 sea vee or contender or venture but couldn't quite do it. The 36 contender would get my attention. But then again you have the 33 foot cat tyhat rides even better so you really have to ride them and see what u like best!
Funny how all the "time challenges" to go Hawaii-midway or NY to bermuda have been set by what....................26'CATs. There isnt a better boat in that size range. A displacement cat has a lot of advantages over a planing mono when the going gets rough. cutting THRU the top 2' of a wave instead of going over it is a start.
Performance always depends on lots of factors, upsea, downsea, upwind, downwind, etc. I have seen a 26GB do 40+ in solid 5' sloppy seas.
quote:Originally posted by MIKE F:
I remember a number of years back, like early 80's, in offshore racing, if the water conditions were rough, the deep V offshore boats would run past the cats, while they couldn't keep up with them in calmer water. I don't know if they've redesigned the cat hulls since then, but that's the way things were, way back when.
Offshore racing and fishing boats are two different types of boats so you can't compare the two.I agree 35 in 6 to 8 footers is not happening in a cat or a contender and I have fished both.
there is two basic types of cat's on the market today planing and semi-displacement(there ARE displacement but lets not worry about em)
your fast cats are true planing hulls your slow ( but very gas conscience) cats are semi-displacements
there is one other type that is modeled after the offshore racer (the half hull)
the Reasons that cats can run faster and flatter and cheaper is two fold
#1 they ride on a cussion of air
#2 their hull (on most small boats) is only about 3ft wide total with a water surface area of 2-2.5 with a very narrow/Fine entry
Lets compare the above to lets say a contender you have 9'ft of surface with 9'feet in the water you entry might be narrow but it's NOT 2' it's more like 6feet @ 1/4 hull
Now lets just take a look at the boat a little closer the faster you go in a cat the less weight is on the boat due to aerodynamics (yes lift just like an airplane)
With a contender the faster you go the harder your gonna hit and the more effort your engines will have to put out to compensate for the hit
This issue of speed in rough water has been bothering me for a while, and it now seems a little clearer.
It seems to be that although cats will generally ride better than monohulls, they really come into thier own when the chop is about 3-4 feet. To be honest seas higher than that are just too much, and there is a fine line between having fun, and when its just not worth it.
Regarding the racing boats, yes you guys are right about them being a different animal comapared to a fishing boat. However having said that all the UIM class (offshore power boats) are all cats. Those boats can take some interesting seas, and at the same time go pretty fast.
I will address this issue as it pertains to the GB 260.
This boat will chew up 1-2' even mono drivers are impressed. at 3-4' depending on period 25-28kts is still a fairly comfortable ride... 5-6... 20kts maybe 18kts is more reasonable.
Ihave been out in no shit 8-10's.... and that is just a slug fest 12-13kts maybe.. with bluewater over the bow.
The problem with this comparison is that certainly... a correctly powered 25 contender/reg etc.. can outpace a cat....BUT at what price... the pounding is just not worth it.
Most cat owners ( even the faster worldcat guys ) buy their cats for the ride ... speed being down the list. We bought our GB because of the ride and cockpit space for fishing.
Bottom line is that they are all good boats.. ride what you think you like .. before you decide...
but any yahoo... mono or cat driver who tells you they ran 40kts in 6-8'...well they might do it.. ONCE. And certainly not for very long.
Hell most people think waves are bigger than they really are anyway.
I run my Worldcat 266SC almost all the time at 30 mph. Flat conditions 30 mph, 1-2 or 2-3 chop I go 30 mph. I will often pass up much larger boats who have slowed down for comfort. If things get 3-4 I might slow to 25. The fact is it is tough to beat the chop absorbing qualities of a cat. You might also be surprised how little thought I give as to wave direction other than trimming things for the conditions. Don't ever ride in one or you will surely remember next time you are getting pouded in a monhull.
I guess the new wave measurement standard is trough to peak, instead of sea level to peak. It does sound more impressive that way. Plus, a lot of boaters haven't really measured a wave height objectively.
It all comes down on this forum to "it looked like 6-8'. Go out to a jack-up rig, and measure the high and low points, average a set, then time the frequency for the real story and the big picture. In the old days, you would then divide the total height average by 2. It is a rare day here in the Gulf that waves exceed 3-4 by the old standard of measurement. And that's rough even in a 34' deep V at 25 mph!
Catamaran Speed in Choppy Waters 
