Motor size for Tom Cat

The price of a TC 255 with trailer and power starts close to $120K. By the time you add electronics, upgrade the charger, wiring, generator, AC etc you are fairly easily at $150K.

We keep the boat in cruising mode, and she rides level--no bow down.

We have not had any significant water in the scuppers even in heavy weather--but again we don't keep a lot of weight. The extra batteries are under the dinette --only item aft may be the generator and inflatable, but we try and keep these foreward in the cockpit.

Putting weight in either end of the boat makes it pitch or hobby horse more.
 
Thanks for the input, we appreciate your experience and tips. We had demo of 25 Ranger and Tom Cat. First Mate & I fell in love :love with the Tug but because I have had operations on both my ears diesel sound and I just don't get along. The Tom Cat was everthing we expected in the water but after seeing the beautiful finish and the many extras in the Tug the Cat is tens of thousands too expensive. So like you JimD I guess we will remain Bayliner alreadybe's and C-Dory Wanabe's
:sad
 
A Basic TomCat 75k with Twin Outboards 30k basic stove..sink with out any toys ..without trailer (I don't want or have one) good to go costs about 105k+
When you add a trailer 10k..Refrig.1k..windlass1k...rear station3k..dual electronic controls 8k...digital fuel guages1k....electronics15k ect ect
140k+

Dick
 
OK, so in the old days we learned about hp rating based on that "displacement factor" formula from the USCG. Seeing as that was/is weight based, and that the 175s from Evinrude (and Honda too?) are the same wieght as the 150s, has anyone tried these out? ...disregarding the NMMA and your insurance company :twisted: I remember we worried about "surge torque" on the transom with very high power obs as much as weight (hehe we just wanted to go fast), but that seems to be a non issue with the Armstrong brackets.


PS I also heard from a "little bird" that initial TC 255 testing was done with twin 200s ..not sure if that is really true,, but I guess I still like fast even though I am in my 50s now :mrgreen:
 
JimD":3klea5bp said:
PS I also heard from a "little bird" that initial TC 255 testing was done with twin 200s ..not sure if that is really true,, but I guess I still like fast even though I am in my 50s now :mrgreen:
Click to expand...

JimD-

I kind of find it hard to understand why they would test with engines that weigh 110 lbs each* more than the 150's they probably thought they'd wind up with. Seems the added weight would throw the test off quite a bit. But anything is possible! Maybe they thought the cat could take 400 HP!

How fast could you go with a pair of 300's? (Just kidding of course.)


Joe.

*
150= 478 lbs
200= 588 lbs
(long shaft versions)
 
The intial TC 255 testing is well documented on this list--and it was with Honda 130's or 150's--not 200's.

The Suzuki 150's and 175's are basically the same engines. I would see no real reason why one could not use the 175's--and get a little more top end speed. But I would not do it--because the 150's give adequate speed. The forces on the transom are related to the weight of the engines, as well as the hp, the sea state and characteristics of the hull as it goes thru the water.
 
Finding the line between planing and displacement speeds are difficult on a TC 255. Many cats are displacement or semidisplacement hulls and do not plane. If the Tom Cat didn't drag the bridge deck it would act more like the "normal" semidisplacement cat.

We spent several hours running the boat at planing down to displacement speeds. We found that trimming the bow down at 20 to25 knots decreased the effeciency by decreasing the speed slightly and requiring more fuel. We noted that as the boat become less effecient, the rooster tail decreased. As we dropped the speed, we could keep the boat semi planing down to about 9 knots. But there was dramatic change in the quarter wave and in the power required to keep the boat at that speed--thus the effeciency dropped to half of what it was at 20 knots.

For a boat to plane, it must climb over its bow wave, and as this occurs the quarter wave (which is "wake" as we normally define it)--decreases.
As we brought the boat down to the lower speeds, the wake (quarter wave) became very large--over 3 feet--vs only a few inch wake at high speeds. Fuel consumption went from 2.3 miles a gallon to less than one mile a gallon. Also at a definative speed of 9 to 10 knots (with the bow trimmed fully down), there was a large amount of water pushed up around the outboards--well half way up the cowlings. When we tried to turn at this ineffecient speed, this wave was actually pushed up on the motor bracket and slopped some of the wake into the cockpit.

My conclusion is that my boat will not plane at 8 knots--and at 8 to 10 knots the boat is running in a displacement mode, not a planing mode, despite being able to keep the bow down. The tunnel was not clear at these speeds.
 
Jim D,

Another thought is that a lightly loaded TomCat can go pretty fast with the 150's, even at below max throttle. We were showing 39 Knots at about 5300 rpm and that feels pretty darned fast in moderate seas in a boat that size. It'd be tough enough to dodge a log at that speed!

John
 
drjohn71a":195lz6ti said:
Jim D,

Another thought is that a lightly loaded TomCat can go pretty fast with the 150's, even at below max throttle. We were showing 39 Knots at about 5300 rpm and that feels pretty darned fast in moderate seas in a boat that size. It'd be tough enough to dodge a log at that speed!

John
Click to expand...
Hehe this is mostly an exercise in "because I can" As a teenager in the late 60s early 70s we were putting the tall Merc 115-135s on things like my 15 foot Wagemaker(so we could barefoot ski), and 12 foot hydroplanes. Although the static down force from the weight was ok just sitting there and moderate accelleration to wot was ok...the surge torque from a 135 at 0 - wot on a 12 footer could snap the transom like match stick on some of those old boats, and over time create fatal stress cracks on others.
I really like the Tomcat, and even as I am in my 50s now, there are times that I would like to be able to wot out to well over 43 knots. ( my boat will do a little over 40 knots on the gps now with one person)
Having said that, nobody really needs to go faster than 39 on the water :smiled
I have narrowed my search to either a Tomcat or a CD-25.
I am having "discussions" with my wife now, as she wants a "cave" boat ( I despise them) , and if she sees this post, I am sure that a CD-25 will be much more to her liking than the Tomcat. :smilep
 
My esperience is that once a wife has spent a night or two in the cave of an express cruiser, the open pilot house of either the CD 25 or the TC 255 is like a revelation. It is so wonderful to watch the world go by as you sit at the table and have protection from the elements. Jim D's area the pilot house makes a 4 season boat (I lived 2 1/2 years in that area of the Chesapeake/James River).

The only advantages I see of the CD 25 is a smoother transition from displacement to planing speeds--(but I didn't post how the TC behaved with bow up at the lower speeds). The CD 25 is cheaper, one engine better fuel mileage, but you won't get the 49 mph top end when light. The other day we had full tanks, with 4 good sized people and all cruisng gear aboard. We still had top speed in the mid to high 30 knots.
Both boats are good and will work.
 
Bob, that statement " but you won't get the 49 mph top end when light" is a key to this whole discussion on speed. When a cat is lightly loaded, they are really fast, BUT when you put weight in them for cruising they become similar to a monohull. Keep the Tomcat lightly loaded, and it'll scream; load it for a cruise, and it ain't that fast. Thats why cruising cats are BIG and racing cats are small(er). As you know.

On our CD-25, when I took the cruising gear out of it last fall and then went out on San Diego Bay, Our Journey just screamed. Now, I'm putting that junk back in for this summer's cruise. Arguing with Judy all the way.

Remember: light is fast.

Boris
 
Journey On,
Yes, definately the cats do better when light--but actually the planing cats are not like the displacement sailing cats, or even the cruising power cats, which do end up as slow as most monohulls. We are talking planing boats and boats with lots of HP here.

My experience with the CD 22 (I have not owned a 25, yet)--is that 30 is about the desirable top speed--they get a little skitterish above that speed and with 90 hp our 22 would get into the low 30's even loaded for cruising.

The Tom Cat 255 can still cruise at 30 to 35 knots fully loaded. There is a price you pay--and it is more fuel--the CD 25 will most likely be a more economical boat to run--with one 150 hp vs two 150's for the TC. The TC's still run at 2.4 mpg when loaded for curising at 25 knots--I don't know about the C D 25's.

Regards
 
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