using paravane on outriggers for stability, and other cruising questions

[irishman]

I'm new to this forum, so pardon me for my lack of knowledge RE: Hatteras 37c 1980. I'm seriously considering a 37C, with 671ti"s, as a cruising boat for the Caribbean. My questions are;
Can small (ish) paravanes be used off the outriggers to stabilize the vessel for hull speed cruising?
Can I use 1 main at a time to cruise, without causing overheating or other negative issues?
What could I expect my fuel consumption to be at hull speed?
All the above assumes that the DDs (rated at 425 hp) are in good shape and well maintained.

[Boatsb]

Don't buy a truck to do the job of a prius.

The outriggers will snap as they are not made to handle that much pressure. The boats made to plane. Kicking around at hull speed will not be optimal.

[irishman]

Thanks Boatsb for the quick reply, the reason the hull speed is important is that getting to the Caribbean requires a long range not easily supported by the 350usg tanks. Sport fishermen are a lot more stable on plane but at the expense of range. yes I can increase tankage with bladders, or extra installed tanks, or even 55usg drums, but at the expense of vessel trim, (and frankly cost) so all of these questions are of prime importance to me.

[Boatsb]

We have boats going to tbe bahamas all the time with 300 gals. It's less than 100 miles to cross. Fuel is available in the islands. Troll over and save fuel. It's done all the time. But be able to run if weather comes in.

[jim rosenthal]

Not as many boats have paravane stabilizers as used to, because there are internal gyro systems out now which work pretty well, from the limited experience I have had on boats with them. But if you look at paravane systems on cruising powerboats, they are very robust- and so are the parts of the boat that they are attached to. I can't imagine sportfishing outriggers being able to do what you want. Something would certainly break- or tear the outrigger off the side of the boat.

Since you are worried about fuel economy, perhaps you should look for a similar boat that has had modern four-stroke diesels installed. They use less fuel than DDs.

425hp is a lot out of a 6-71 DD. Since you plan to cruise at low speeds, you might be better off with a boat with one of the lower-hp rating DDs, if you could not find a repowered boat. I think all other things being equal, the higher-hp versions of the 6-71 didn't last as long because they were required to make more hp.

[wpc691]

We were also interested in hull speed cruising, that's how we wound up with our 43MY with Cat 3208T's (302 hp). We get great fuel economy, 3208's are relatively quiet, and you'll appreciate their small size when you get in the engine room to do something. We cruise at 8mph, but can do 16 if we want/need to. Problem is, you'll never (?) find 3208's, at least low horsepower versions, in a sportfish.I researched paravanes a little when we were considering displacement trawlers (Willard, etc). As pointed out above, the forces generated by paravanes are substantial, and they require true booms for operation. Your outriggers likely wouldn't last through a single swell.

[irishman]

Thanks for the replies everyone, I can see that a paravane would exert a massive amount of pressure on an outrigger. Would the outriggers themselves act as a balance pole and increase stability to a lesser degree, by themselves? Yes, I will be doing a lot of trolling enroute.

Regarding the mains, is it feasible to detune the 671 ti's by changing injectors? I don't require the big hp, I prefer the reliability.

How is fuel burn at or below hull speed on these engines (With properly matched drives and propellers)? I agree that a repower would be a good move, but very expensive. I'm not yet locked in or committed to a particular boat, so looking elsewhere is still possible.

Luckily, almost every island in the Caribbean is not far from each other. I do agree with the ability to outrun weather, which is one of the reasons why I'm favoring the versatility of a sportfisherman (fishing and diving being among of the others).

[bobk]

Thanks for the replies everyone, I can see that a paravane would exert a massive amount of pressure on an outrigger. Would the outriggers themselves act as a balance pole and increase stability to a lesser degree, by themselves? Yes, I will be doing a lot of trolling enroute.

Regarding the mains, is it feasible to detune the 671 ti's by changing injectors? I don't require the big hp, I prefer the reliability.

How is fuel burn at or below hull speed on these engines (With properly matched drives and propellers)? I agree that a repower would be a good move, but very expensive. I'm not yet locked in or committed to a particular boat, so looking elsewhere is still possible.

Luckily, almost every island in the Caribbean is not far from each other. I do agree with the ability to outrun weather, which is one of the reasons why I'm favoring the versatility of a sportfisherman (fishing and diving being among of the others).

Irishman,

I'm a long term cruiser with minimal knowledge of these big diesels. But I'll chime in anyway and smarter guys than I will set me straight :p.

First, if the boat has Alison transmissions, you cannot let one free wheel while operating on one engine. The oil pump is on the engine so if it is not running the gears will wear. You can of course lock a prop shaft to get around this. I believe there will be a modest fuel savings, others here do not.

I have been running 425HP 6V92 TA's at 1000 rpm for more than 3500 hours with no ill effects in a 1981 48MY. I do use a good cetane improver to help get a clean burn. My last 1200 mile trip generated almost no soot on the transom. Your 425HP 67i TI's are producing the same HP from a smaller engine. What is probably important is what is the compression ratio difference and exhaust temperatures. That gets into loading the engine. Lots has been written on the HOF on these issues and it would be worth searching and reading if you do want one of these old girls. In particular read Brian Degulis' posts and Genesis' posts. The usual conclusion is it is not feasible to de-tune the engine for your purposes.

On mine, 1000 rpm gets me about 1.2 NMPG at about 8 knots including about three hours per day of generator run time.

I would not expect any stability effect from the light weight of the outriggers.

Bobk

[irishman]

Thanks for the continuing replies, as I am digesting all of this, I keep coming up with more questions:
Is there a direct swap for the 671ti's that leaves the current drives (I believe they are velvetdrives)?
Is this something a retired geezer ( me, reasonably mechanically competent) can do at a diy yard?
Can this be done economically ( I am after all, a retired geezer)? what would be the ballpark costs?
Given the expected short life of the 671ti's, could I do an inframe rebuild to derate hp, and increase reliability?

keep in mind, this will be my retirement home for the next few years. I don't want to have to worry about propulsion failing while offshore (I don't think a 37c would be easy to row).

[Avenger]

Buy an LRC instead.

Scott was right, you're trying to turn marble into mahogany. A 37C is a great boat, but not for the way you intend to use it. Rather than trying to cob it into a trawler that is still not going to suit your purposes and will only end up as a mess just get a trawler/cruiser that was made for what you want to do right out of the box.

Sorry if it sounds abrupt, but this subject has been done to death on this forum 100 times. If you do some searches you'll find all the reasons why it isn't worth the trouble or expense.

[Scarlett]

I have a friend that took a pair of 871ti's and re did them to naturals, it required obviously removing the turbos, but also new exhausts, new injectors and he even re proped it then hardly ever used it, go figure. John

[irishman]

Avenger, thanks for the reply. This exercise in futility was an attempt to discuss with knowledgable persons the suitability of the 37c as a liveaboard cruiser, and in its current condition, its ability to go long distances with the reasonable expectation of getting to its destination safely.
As for your observation that "this subject has been done to death on this forum 100 times", I spent a great deal of time searching threads before I chose to start one, and do not share your view. If you had read my previous post, you may have noticed I wrote that I wanted the versatility of a sportfisherman, along with the ability to outrun weather. If I wanted a slow boat to China, I would get another sailboat (I've had two).
If you are wondering about my experience on the water, let me assure you that I have 22 years in the USN, mostly on patrol craft, and a further 20 years as a merchant marine officer commanding tankers, panamax freighters, and research vessels. My interest in Hatteras sportfishermen goes back to early navy days chasing drug runners, whose preferred vessel was the Hatteras, as they were considered "bullet proof".

[irishman]

Thanks Scarlett for your reply, the information on the 871's are a good starting point for me.
I don't want to derate the mains so much, that in effect I become a trawler, I just want reliability, and maintain the ability to outrun/outmaneuver weather.
I am still in the boat shopping phase, but I want options to explore, like repowering, if an otherwise suitable vessel comes along.

[Avenger]

In that case, I'm glad to see that you are doing your homework. Your research will also tell you that derating the engines has no cost/efficiency benefit either.

I'm still thinking you'd want to look at a Yachtfish or cockpit motoryacht as better suited to your needs. More space and accommodation for the liveaboard, cockpit for fishing and diving and while a decent slow cruiser they can get up if they have to, although usually not as fast as a convertible.

Best of luck with your search.

[irishman]

Thanks Avenger, so far I would say that your advice has lead me to expand my search. I will take a closer look at Yachtfish, and Cockpit motoryachts for suitability.
Let me ask this: how about singlehanding, to include docking and mooring ease?
How maneuverable are they in tight spaces/marinas?
Is there decent range?
I did read several threads on these, and would like to gain more knowledge.

[Scarlett]

Seems like the general feeling on the motoryachts at displacement speeds is a gallon per mile. at 8 knots we do a little better than that with 871ti engines, but we do have smaller injectors than the normal ti injectors, not sure if that really makes much difference but that is what the boat had when we bought it and we are happy with the performance. John

[krush]

A yachtfish or cockpit motoryacht is more likely to have built in stabilizers too. A sportfish, not likely...except the really big ones.