I finally found the boat I want with the engines I want. (Diesels) I know nothing about diesels tho. Are they worth the extra 20g or so? They have 1500 hours on them. What are there normal life expectancy? The boats in Virginia so I'm just trying to get as much info as I can before traveling. What's the best way to decided if I will travel or not?
cat 3116's in 97 330ec
Xplicitlnck
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2,063 Posts
- Location
- New Buffalo Michigan
I personally don't mind dropping the boat in and out of gear in the harbor to maintain no wake. The boats that are "jumpy" and the ones that are the easiest to maneuver at least for me. My favorite so far has to be the 510 with 3406's in it, the boat drops at least 4" down in the transom when put in gear and tiny little inputs correct everything when docking.
The next best is the older 500 Sundancers with the Detroits or Cats, either way a great handling dockside beast.
The next best is the older 500 Sundancers with the Detroits or Cats, either way a great handling dockside beast.
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12,064 Posts
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- Tri Cities, WA
I've never run on one engine because that means the other prop is free wheeling and I've heard/read that is not good for the transmission. Perhaps Frank can shed some light on this topic.
Alex wrote: "I usually don't push mine over the hull speed too much (7.4kts), if the current and/or wind is with me I'll get another knot or so, but 1000RPMs is what I try to keep as my max for slow cruise. Anything over that make less sense, b/c I'm gaining very little speed and just burning more fuel. I don't think I'll ever see anything in between 9kts to 12-13kts. My displacement normal speed is between 7kts-9kts (not adding wind and/or current affects) and slowest planing speed would be just about 13kts (before she starts falling off plane)."
I've found the same thing about moving the rpm's up from idle....the gains get smaller as the rpm's increase. The reason for that is the boat is outrunning the bow wave and the stern starts to settle further down into the water, causing it to plow through the water more. To find out your boats most efficient hull speed you need to know the length of the water line, then use this formula:
![Image]()
where:
"
![Image]()
" is the length of the waterline in feet, and "
![Image]()
" is the hull speed of the vessel in knots
Using that formula, my hull speed is 8.888kts. Anything above that and the efficiency of the hull decreases, up to the point where the boat is on plane, then it rises again. I've never tried to see how slow my boat will run on plane (before it drops off) so I can't give you that info. Once I get it on plane I usually back it off to about 1750rpm's (~80% of WOT). At that rpm it's normally running about 22kts. I leave it there until we're ready to come off plane. When we came back from Portland last summer we ran at that rpm for about 50miles at one point, and the boat loved it. We were running in 5'-6' waves and had a wind off the stern at about 25-40kts. Fuel economy was horrible, and I knew it, but we were trying to make it to our next marina before dark. We came back about 220 miles on that trip and ran about 75% of the trip on plane.
Here's a video I took on the way down to Portland. We were running about 22kts in 4'-5' waves and had the wind on our bow.
[video=youtube_share;WRVlgGbH9U4]http://youtu.be/WRVlgGbH9U4[/video]
I don't have trolling valves but I wish I did. I've learned to move the throttles in and out of gear for just a split second and I'm amazed at how quickly the boat responds to those short corrections. When backing into my slip I'd bet I'm in neutral over 95% of the time as the stern gets close to the slip opening.
Alex wrote: "I usually don't push mine over the hull speed too much (7.4kts), if the current and/or wind is with me I'll get another knot or so, but 1000RPMs is what I try to keep as my max for slow cruise. Anything over that make less sense, b/c I'm gaining very little speed and just burning more fuel. I don't think I'll ever see anything in between 9kts to 12-13kts. My displacement normal speed is between 7kts-9kts (not adding wind and/or current affects) and slowest planing speed would be just about 13kts (before she starts falling off plane)."
I've found the same thing about moving the rpm's up from idle....the gains get smaller as the rpm's increase. The reason for that is the boat is outrunning the bow wave and the stern starts to settle further down into the water, causing it to plow through the water more. To find out your boats most efficient hull speed you need to know the length of the water line, then use this formula:
where:
"
Using that formula, my hull speed is 8.888kts. Anything above that and the efficiency of the hull decreases, up to the point where the boat is on plane, then it rises again. I've never tried to see how slow my boat will run on plane (before it drops off) so I can't give you that info. Once I get it on plane I usually back it off to about 1750rpm's (~80% of WOT). At that rpm it's normally running about 22kts. I leave it there until we're ready to come off plane. When we came back from Portland last summer we ran at that rpm for about 50miles at one point, and the boat loved it. We were running in 5'-6' waves and had a wind off the stern at about 25-40kts. Fuel economy was horrible, and I knew it, but we were trying to make it to our next marina before dark. We came back about 220 miles on that trip and ran about 75% of the trip on plane.
Here's a video I took on the way down to Portland. We were running about 22kts in 4'-5' waves and had the wind on our bow.
[video=youtube_share;WRVlgGbH9U4]http://youtu.be/WRVlgGbH9U4[/video]
I don't have trolling valves but I wish I did. I've learned to move the throttles in and out of gear for just a split second and I'm amazed at how quickly the boat responds to those short corrections. When backing into my slip I'd bet I'm in neutral over 95% of the time as the stern gets close to the slip opening.
Joined
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12,226 Posts
Some transmissions can be damaged by allowing the prop to windmill and turn the transmission output shaft; others can free-wheel without hurting anything........just depends upon what transmissions you have.
The other concern about free-wheeling shafts is the potential damage to dripless shaft seals if you do not have cooling water flowing to them.
The other concern about free-wheeling shafts is the potential damage to dripless shaft seals if you do not have cooling water flowing to them.
If Steve500Dancer's 2 Stroke catastrophe was unrepresentative of a typical diesel "big bill", what are some of the more common "big" issues you get with marine diesels? A "rebuild/recondition" of a gasser is fairly well understood and there are usually long/short block options that don't cost a whole lot more, what are you in for with diesel?
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12,226 Posts
Overheating is probably the most likely thing that causes a diesel failure. Diesels are very unforgiving when run too hot. There is a lot of cast iron to heat up so expansion causes some pretty serious issues with heads, liners, pistons, and other tolerance fit components.
Overloading is also a common issue.....either over a long period of time or even a short span like running several hours at rated rpms on one engine with the other one out.
These are the big causes of problems, but as you can see they are easily avoided and only occur to those who don't understand overheating or overloading. They happen far less frequently than a gas engine needing to be replaced because a riser/riser gasket failed and filled the engine full of water.
You said the 2 stroke catestrophe was unrepresentative.............not really true. 2- stroke diesels have 2X as many compression strokes per hour of running than a typical 4 stroke engine. Detroits in particular seem to need a top end reman at something like 1800-2200 hours. Because of their design, you seldom can just "freshen up" a Detroit and they require complete cylinder kits when you get into one of them. Since Detroit doesn't make the 2 stroke anymore, parts are kind of expensive. This is not an issue one is likelt to have with Cummins, Caterpillar, Volvo, Yanmar, etc. engines.
Overloading is also a common issue.....either over a long period of time or even a short span like running several hours at rated rpms on one engine with the other one out.
These are the big causes of problems, but as you can see they are easily avoided and only occur to those who don't understand overheating or overloading. They happen far less frequently than a gas engine needing to be replaced because a riser/riser gasket failed and filled the engine full of water.
You said the 2 stroke catestrophe was unrepresentative.............not really true. 2- stroke diesels have 2X as many compression strokes per hour of running than a typical 4 stroke engine. Detroits in particular seem to need a top end reman at something like 1800-2200 hours. Because of their design, you seldom can just "freshen up" a Detroit and they require complete cylinder kits when you get into one of them. Since Detroit doesn't make the 2 stroke anymore, parts are kind of expensive. This is not an issue one is likelt to have with Cummins, Caterpillar, Volvo, Yanmar, etc. engines.
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3,017 Posts
That seems opposite to me. Wouldn't the increased drag on the unpowered side increase the boats tendency to pull to that side?
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4,024 Posts
The confusion comes from the way SeaRay wires tab buttons. If you're only running your stbd engine, pushing your port tab BUTTON, actuates the STARBOARD tab.
(which is how I prefer it btw. Each time I drive a Formula, I lean 'er over about 52 degrees until I remember to use the opposite of my trim tab instincts!)
I've used the 1-engine + tab technique in special circumstances, such as transiting the Welland Canal between Lakes Erie & Ontario. Sometimes the slow idle & neutral time can be hours and hours. The tab doesn't have much effect while in gear, but it helps correct the course as I coast.
Joined
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9,346 Posts
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- Miami / Ft Lauderdale
Interesting approach on using a tab to help the rudder. The way I see it, it's just another way to create a drag on one side to help correcting of straight course. My question is, why do you find beneficial to add another component (trip tab) to the mix of things if you still have to adjust the rudders position, just a little more if not touching the tabs. IMO, no matter how you twist it and turn it, the bottom line is that a drag is created to change or maintain the course, regardless what method is used. It seams to me that adding tabs in to the mix just adds another item to keep an eye on and remember to reset when both engines are engaged later on.
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4,024 Posts
I can't argue that it's one more thing to fuss with, one more thing to remember. Single-engine handling is awkward though, so sometimes you want to leverage every advantage you can. When hard-over isn't enough, the tabs can add just enough to make the difference.
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9,346 Posts
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- Miami / Ft Lauderdale
I never had trouble making the adjustments with the rudders only. One time I had to bring my 320DA for service 2hrs away on a single engine. The highlight of the trip was going through very narrow with strong current Point Pleasant canal. I did it at night to minimize the traffic issue. To my "luck" there was a local dinner cruise steam boat "River Lady" that I had to pass inside the canal b/c it was going too slow for me. With enough RPMs on one side I was able to do it without any troubles and rudders did a good job steering the boat on course.
Even though I never had the need for using the tabs when operation with one engine, I guess it's good to have the option in the "toolbox".
Even though I never had the need for using the tabs when operation with one engine, I guess it's good to have the option in the "toolbox".
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7,965 Posts
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There is a boat in our club (an older 340DA I believe) that had lost his steering and didn't fix it for around 2 seasons. He ran the boat steering with his tabs & throttles while underway and using his transmissions in close quarters. Steering wheels are overrated.
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9,346 Posts
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Careful there chief. Good enough guy but is busy taking care of his wife who is suffering from dimentia.
dimentia
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9,346 Posts
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Sorry Ken, I don't mean to insult anyone. But, if the captain was able to find the time to cruise for two years there has to be a time frame when a steering issue could be addressed.
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I agree
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4,036 Posts
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- Long island ny
Now ya gotta go and take a joke and turn it into a seriouse matter and make him feel bad. Not cool man not cool. Its all jokes
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9,346 Posts
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- Miami / Ft Lauderdale
No worries champ. Ken and I are cool. Perhaps the other captain is his friend and I totally understand level of the sympathy.
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6,232 Posts
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- Long island , NY
Typical Alex!! Always making trouble!! LOL
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