255 T-Cat Questions

[CapnMike]

OK, I've been lurking on this site long before joining, and congratulate you all for a great site. There are few marques that have such an active and knowledgable owner base.

I'm contemplating moving from a 24' high-V monohull to something about the same size with a larger cabin. I'm looking for something I can run at speed (25-35 mph) comfortably, on the Columbia River's waves and chops, and yet fuel miserly at displacement speeds. My research tells me a catamaran may do both, and I'm narrowing to search down to a 255 TC (or a Glacier Bay, or....).

I think I've read most of what's been said about the 255 TC. From my readings, I get the impression that: 1) the 255 TC is perhaps too sensitive to aft weight; and 2) efficiency suffers at lower than planning speeds. I'd like owners' comments; am I reading too much into casual comments?

I've considered a partial solution to aft weight concerns would be twin 140 Suzukis (great reputation), which appear to be almost 100 lbs lighter than a pair of Honda 135/150. Any thoughts?

As to 2), is it possible that, at plane, the 255 enjoys aerodynamic advantages, similar to tunnel-drive speedboats? Such designs often enhance performance and ride while planning @ speed, but do little for efficiency as a boat falls down into semi-displacement speeds. In other words, inefficient, comparatively high fuel burn @ lower speeds, similar to my present boat.

What think thee?!

[drjohn71a]

CapnMike,

Alot of what we've said on here is kind of the 'free thought' process, i.e. relating what we 'think' might or might not be a problem.

As for me, I have extolled many times the benefits of light loading.... BUT, after using the TomCat about half a year, mine is loaded to the hilt - A/C, genset, spare genset gas, dual anchors, four coolers, double just about anything, etc.. And, you know what? That TomCat is like a tank with wings... we ran the 28 mile Galveston Bay out to the Gulf at 38-40 smph with no problems. Our fuel usage was so low that the gas dock guy could not believe a boat that size could run out to the 10 mile offshore oil rigs and back for the fuel we were buying daily. We routinely ran 2-4 foot seas at 18-25 smph, anchored, drifted in 5-6 foot seas and surfed back on the swells at 22 smph in 4-6 foot (downwind) seas. The TomCat is an amazing performer in my eyes.

I am thinking that the Permatrim foils help alot to get the bow down in higher waves (over 4 foot) and that is really appreciated after 12 hours of fishing in rough waters.

With all the weight and extra equipment on my boat, we averaged 1.8 smpg over hundreds of miles in 3-6 foot seas over a week on the Gulf of Mexico. There were times we were speeding along at 2.5 smpg, short times of hull speed at 7 smpg, but most time from 16mph and up. The gas dock attendants said we were using about half the fuel of comparable boats filling up and going out the same each day as us.

Now, the CD 22 is a real miser, and a 19 or 16 even better, if fuel efficiency is your top priority. The CD 25 gets a bit better mpg than the TomCat.

I think you should fly or drive somewhere and sea trial a TomCat. That boat has a unique feeling of comfort and control at all speeds that is tough to match.

We had to tilt engines up and squeak by some shallows under 2 foot now and then and there are not many larger craft that can do that.

I've towed it over 1500 miles so far and the boat/trailer combo is A-one stable and well behaved. Getting on and off the trailer so far has been a breeze - easier than some of my old, smaller craft.

It is not often you buy something that keeps surprising you into appreciating even more it's design and potential, but the TomCat just keeps doing that to me.

Good luck,

John

I think you have to get the 150's no matter what brand. The Honda 150's operate as 135's until you get over 4500 rpm and are whisper quiet. Dr. Bob of Thataway is a fan of the Suzuki 150's with their larger props.

I think the Glacier Bay operates more like a displacement hull and has a smaller cabin per length. While you'd likely be able to go faster in 5 foot seas, the fuel economy is likely worse and I don't think it planes at as low a speed as the TomCat. The harder chined TomCat is an extremely stable platform and has a rock solid feel of control - no squishy, wishy washy-ness there.

Regarding reduced efficiency at lower planing speeds, I think those comments reflect what happens if you trim the engines or permatrims down below the normal planing speeds. Just like trim tabs, if you tilt them down, they inhibit forward progress in order to raise the stern. We have only seen this effect when trimming the engines down to hold the bow down while going upwind in seas 5-6 foot. Even heavilly loaded, the TomCat planes at pretty low speeds with the engines trimmed neutral. 90% of the time, our engines are set exactly neutral (horizontal).

[drjohn71a]

Relating to higher fuel burn at lower speeds, that is the norm for a planing boat, and the square tunnel of the TomCat wets alot of surface below planing speed.

What I am finding is that at 9-12 smph, you'll be burning more fuel than at 22-38 smph. While I have not scientifically investigated the ultimate efficiency speed, we were getting excellent smpg at 5-7 smph. At some points 6 smpg and usually 2.5-3 smpg. But, remember, we were only glancing at the flow guages occasionallly and tides, currents, nor winds were figured in. If you want to go really slow and efficiently, some have cruised on one engine alone. The sea was too rough for us to try that this trip.

So, if you start pushing the throttle above the most efficient hull speed, you'll burn more gas than at speeds above and below that.

John

[thataway]

Dr John has pretty well nailed it. I am sure that some of my comments is what you have read. I must say that people aft, makes much less difference than in a V hull. Yes, if you are at a certainl critical speed, there is a minor issue. But that is only between 9 and 10 knots--not a real good speed--and is in our boat--may be different for boats rigged differently.

We have run in some fairly good seas and always find it much better on top. I am familiar with the Columbia, and I think the Tom Cat would do very well there. We run in the mid 20's because it is the more economical speed, but we can run in most seas in that. Even loaded we can get up in the mid 40's--when the boat was light we were very close to 50. We also have a 9 1/2 foot dinghy, a genset, an Airconditioner, 4 extra batteries, lots of spares, coolers, freezer etc--not a light boat.
We go over a sand bar which is only 18" during the low winter tides--no problems--my V could not get out--even using a kicker, which was above the bottom.

In comparison to the Glacier Bay (and I did two sea trials on the 26)--the 2690 has much less cabin room. The head is in the stateroom, the bunk is smaller and more difficult to get in. the dinette is much smaller, and not usable as a bunk (the TC 255 is). Storage is less in the Glacier Bay, only one burner stove, etc. The Glacier bay does better at the 7 to 11 knot ranges--into waves. (but not perfect there either)--Into the waves at 5 feet the Glacier Bay is better--but again, more spray and occasional "Slam". However, off wind, or beam wind/seas, the Tom Cat is far superior. We have never had the handling problems which are described in the Glacier Bay, and none of the dangerous problems. We have never had water comming in our aft scuppers, when at rest in seas--

Yes, the TC or any cat, depends on air compression in the tunnel for its ride--the Tom Cat does this quite well, I would have liked to see the hullls slightly deeper, for low speeds. The boat is effecient at displacement speeds of 5 to 6 knots. (my fuel flow meters have difficulty reading the differnce between idle and 2 to 5 knots) The fuel effeciency is going to be good in any boat at those low speeds. More important is at the high speeds. Very stable when drifting (more than Glacier Bay).

I had a 27/28 foot deep V before--no question going into waves or wakes, there is no comparison TC much better.--same hp and weight--and about 50% better mileage in the Tom Cat. We will run 250 miles a day, and it is just like going for a drive in the car. Sometimes in the boat it is faster along the beach than the car, because of congestion!.

Go for the 150's. The 140's and the 115 suzuki are on the same platform. The 150 and 175 are same platform. You want the displacement for the torque. Put the 100 lbs in batteries foreward on the port side. The 100 lbs does not make a difference. Also the 150 swings a bigger prop--more effecient. Great engines. I am sure that the 150's will get the same longivity (up to 10,000 hours in commercial service) as the 140's (CG and charter boats reporting from 5,000 to over 10,000 hours)
Having the extra acceloration is important in working seas, especially in beam and down waves--I am not sure that the 20 hp is all that much, but the torque is...

Get rides in both GB and TC under several conditions. I had to take several rides--be sure and take the spousal unit along--she will make the difference! One friend of mine who has ridden in all of the various small cats, chose the Tom Cat and is elated with it.

Good hunting.

[CapnMike]

Thanks so much for your prompt reply.... there is a dealer across the river in Portland, and after I've done my due diligence, I intend to do a test drive. There always appears to be at least one in stock (thank goodness always the wrong color, or I'd own one now), and I see at least 2-3 TCs were sold by the dealer just this year. A couple of the buyers are on this site, so local knowledge will be sought....

You mentioned Permatrims on your boat. In looking at your album, the photos don't show (or maybe I'm blind). If you've discussed them, I'd appreciate a link to your thread.

Wow...all the gear you carry. And I thought I was a water pack rat! But I understand completely: there's nothing worse than needing something on a long-anticipated trip and leaving it on the dock.

Your milage doesn't sound bad at all; I'm lucky to get 1.8 smph at my best with one 200 HP engine. And I'm tired of getting beat up, especially in the windy stretches of the Columbia.

[CapnMike]

And while I was answering John's reply, Bob's came in. Thank you very much. The advice is much appreciated.

I've also considered ETech....their newer 2-strokes give great torque and are as light or lighter than the Suzuki. But it seems as though the PacNW (or at least Portland area) has a dearth of Bomb dealers. Further, the local C-Dory dealer carries Honda and Suzuki, so I guess that's academic.

Bob, you're certainly right about the spousal unit's approval. I've bought too many boats that suited me. Then when I asked, "What do you think?" I'd get an answer I really didn't want to hear!

[mark&diana]

I'm one of the new TC owners and would be happy to share with you what ever I can.

[thataway]

I am not personally convinced that the Permatrims have added much. I put them on, and have left them on. They do put the bow down more at low speed, and drop the planing speed several knots. I don't have any evidence that there is an increase in fuel economy. Top speed may be slightly decreased--but minimal. The Permatrims are at the surface--no water flowing over the top when at good cruising speed. The cats with the brackets run with engines higher than a conventional monohull.

I have not yet found a place where I had wanted to stay at this low planing speed for a lenght of time....But this just has to do with my personal habits...

[drjohn71a]

I agree with Dr.Bob's general outlook on the Permatrim use. There is a specific time, however, when you're going into rough seas, when lowering the Permatrims reduces or stops the vertical bow movement and allows you to go faster without pounding, that I really appreciate.

I think there is some effect, even tho' on top of the water, similar to lengthening the hull on performance.

John

[Doryman]

I was planning to run some tests to see if the Permatrims could help correct the starboard list tendency of the TCs. No one has mentioned this potential benefit here.

I even went out and bought one of those List-O-Meter thingies.

Warren

[drjohn71a]

Hey there, Warren,

I am thinking that the best way to fix that list is to install some weight on the port side. It seems like an odd thrust pattern would come about by running one engine higher or lower than the other which could reduce efficiency. I had a fourth battery installed under the port dinette area, and you could bypass the hot water tank when you dont need it on the starboard side.
They sell bypass kits at the RV places.

Let us know how your tests come out! I am anxious to see what happens.

John

[Doryman]

This winter Les is going to install 2 house batteries and an inverter under the aft port dinette seat so that should help.

Les is also going to install a set of valves so the engines can draw from either tank. With that, I could draw down the starboard tank first.

You may well be right about the thrust pattern. Fortunately, I have a fuel management system. However, it doesn't report individual engine gas consumption. That is a minor matter, however, as I can learn a lot from overall efficiency data.

Warren

[Sarge]

I have a CD25 and kind of wandered into this conversation because I'm nosey, but it is my understanding that the TCs don't/can't have trim tabs? I use my trim tabs a lot to balance my CD25. Can you simply trim the motors on the TC separately to balance the boat? Did I just state the obvious? Should I just stay out of these TC conversations?

[drjohn71a]

Sarge,

You're right on to the question we're pondering right now - What is the effect of trying to level the TomCat using engine trim or permatrims? I think it would effect other C-Dory models with dual engines as well.

Warren, I have the Honda digital guages with inidividual engine fuel flow readouts, but it seems to read the same on both engines. I am not certain that it really does read them individually. I am thinking of leaving one at idle while reving the other up just to see if the port/starboard readouts vary.
I guess a secondary question might be - "Would it be better to trim/balance a boat with trim tabs or engine trim?

John

[CapnMike]

Since starboard list seems to be an issue that everyone seems to agree about, has anyone asked the factory to mount the batteries on the port side?

Should I order new, I'm thinking that's an item on the checklist.