8.1L Crusader Fuel Consumption
I'm considering the purchase of a 2001 Silverton 410 Sportbridge with twin
Gas 8.1L Crusaders (425HP) each I'm concerned about gas engines in a 41 foot boat. Will it struggle to get and stay on plane? How will it maintain speed in following seas? but most importantly, how much gas will it burn??? I've seen the thread where you divide the HP by 2 for cruising HP and then average 1gph for every 10hp, but we are talking about a 30,000+ pound boat with a flybridge, thats like pushing a brick through the water... lastly, anyone know what the approximate cruise speed and RPM's are on this boat.... THANKS!!! |
8.1L Crusader Fuel Consumption
khessert wrote:
I'm considering the purchase of a 2001 Silverton 410 Sportbridge with twin Gas 8.1L Crusaders (425HP) each I'm concerned about gas engines in a 41 foot boat. Will it struggle to get and stay on plane? How will it maintain speed in following seas? but most importantly, how much gas will it burn??? I've seen the thread where you divide the HP by 2 for cruising HP and then average 1gph for every 10hp, but we are talking about a 30,000+ pound boat with a flybridge, thats like pushing a brick through the water... lastly, anyone know what the approximate cruise speed and RPM's are on this boat.... THANKS!!! Suggested reading.... http://www.yachtsurvey.com/GasDiesel.htm http://www.yachtsurvey.com/GasNdiesel.htm It may be worth taking some time to read the details contained in these articles. |
8.1L Crusader Fuel Consumption
On Mon, 08 Jan 2007 22:14:04 GMT, "khessert" u30800@uwe wrote:
lastly, anyone know what the approximate cruise speed and RPM's are on this boat.... With the correct props cruising RPMs should be in the range of 3200 to 3400 assuming 4400 to 4800 at WOT (Wide Open Throttle). Fuel burn will be in the range of 40 to 50 gallons per hour at cruising RPMs. Speed is harder to predict but 18 to 20 kts seems reasonable. A boat that size and weight should really have diesels. |
8.1L Crusader Fuel Consumption
xorbit wrote in :
http://www.yachtsurvey.com/GasDiesel.htm "We recently surveyed a yacht with a pair of 8V71N (naturally aspirated) Detroit Diesels rated at 325 hp that hadn't been overhauled since new 1981. Now, an 8V71 has a 568 cubic inch displacement; the fact that these engines have a 0.56:1 power/displacement ratio explains why they could run so long." There's the engines he's looking for....(c; I wonder what Pascoe's survey was on that boat, vs the same boat in the same condition with two way-past-worn-out gas engines that had been changed 3 or 4 times in those 25 years would have been, given his anti-diesel slant? Obviously, once past the initial cost of two 8V71s, engine costs have been quite reasonable in 25 years of faithful service. Big ol' heavy 2-stroke DDs (71s or 92s) with no turbochargers to catch fire. That's always a winning combination. Change the oil. Let's go to the Med. |
8.1L Crusader Fuel Consumption
Larry wrote:
xorbit wrote in : http://www.yachtsurvey.com/GasDiesel.htm "We recently surveyed a yacht with a pair of 8V71N (naturally aspirated) Detroit Diesels rated at 325 hp that hadn't been overhauled since new 1981. Now, an 8V71 has a 568 cubic inch displacement; the fact that these engines have a 0.56:1 power/displacement ratio explains why they could run so long." There's the engines he's looking for....(c; I wonder what Pascoe's survey was on that boat, vs the same boat in the same condition with two way-past-worn-out gas engines that had been changed 3 or 4 times in those 25 years would have been, given his anti-diesel slant? Obviously, once past the initial cost of two 8V71s, engine costs have been quite reasonable in 25 years of faithful service. Big ol' heavy 2-stroke DDs (71s or 92s) with no turbochargers to catch fire. That's always a winning combination. Change the oil. Let's go to the Med. I went through every article on Pascoe's site. Very informative. But he's definitely a sceptic and the site is focused on fiberglass boats without consderation for steel or other hull materials. Also, pretty much regardless of what he's discussing, the glass is usually half-empty. He certainly wants to make sure potential buyers know what they're getting into. In the context of this thread, Pascoe states that gas engines are not appropriate for boats greater in length than the mid-30 foot range. Those big two-stroke diesels are really something. Real power. (three Tim Allen grunts here.) |
8.1L Crusader Fuel Consumption
On Mon, 08 Jan 2007 20:35:54 -0600, xorbit wrote:
In the context of this thread, Pascoe states that gas engines are not appropriate for boats greater in length than the mid-30 foot range. It's really more a matter of weight rather than length, somewhere around 15,000 pounds or so. My old Bertram 33 sportfish at 21,000 lbs was definitely over the line. It had twin 350 hp Crusaders and they were not nearly enough power, and way too thirsty. |
8.1L Crusader Fuel Consumption
xorbit wrote in :
But he's definitely a sceptic No he isn't. He's a first class ass. That's what people pay him for. More surveyors should be like him. If he says it's crap, it's really crap. I love diesels, have 3 of 4 diesel vehicles, running on used french fry oil. But, I must admit once you factor in how little use a boat really gets for 99% of their owners, he's right about going cheaper gas. The dock condos hardly need an engine that runs at all, just sitting there like most do. |
8.1L Crusader Fuel Consumption
Larry wrote: xorbit wrote in : But he's definitely a sceptic No he isn't. He's a first class ass. That's what people pay him for. More surveyors should be like him. If he says it's crap, it's really crap. I love diesels, have 3 of 4 diesel vehicles, running on used french fry oil. But, I must admit once you factor in how little use a boat really gets for 99% of their owners, he's right about going cheaper gas. The dock condos hardly need an engine that runs at all, just sitting there like most do. One point not looked into is the resale value of a diesel vs a gas powered boat. The diesel is always going to have a better resale. Some points that are hard to quantify are when you have diesel power, the knowledge that it's much more reliable, your just not going to have as many problems, if you maintain them and don't abuse them. The boat will be much more enjoyable with diesels, you've got more power available when, or if, you want it. You can take a boat load of friends on board and it's not going to suddenly slow way down, or not get up on plane. You won't like it when the same boat with diesels fly's on past you. And it's going to be less painful when it comes time to fill the fuel tanks. It's hard to put a price on peace of mind. And I know the price differance is a lot. But if you could have afforded the diesels, and you didn't go for them, you'll find that you will regret not getting them. You'll almost never find someone that has owned a diesel powered boat (that could afford it) purchases a gas powered boat after that unless the boat is much smaller. John |
8.1L Crusader Fuel Consumption
I agree wholeheartedly with diesels being superior, but the gas boat is $155K
and the same boat with diesels is $240K its gonna take a long time to burn $85K in fuel... I want the diesels, but it doesn't make sense in this scenario....anybody agree??? Capt John wrote: But he's definitely a sceptic [quoted text clipped - 7 lines] condos hardly need an engine that runs at all, just sitting there like most do. One point not looked into is the resale value of a diesel vs a gas powered boat. The diesel is always going to have a better resale. Some points that are hard to quantify are when you have diesel power, the knowledge that it's much more reliable, your just not going to have as many problems, if you maintain them and don't abuse them. The boat will be much more enjoyable with diesels, you've got more power available when, or if, you want it. You can take a boat load of friends on board and it's not going to suddenly slow way down, or not get up on plane. You won't like it when the same boat with diesels fly's on past you. And it's going to be less painful when it comes time to fill the fuel tanks. It's hard to put a price on peace of mind. And I know the price differance is a lot. But if you could have afforded the diesels, and you didn't go for them, you'll find that you will regret not getting them. You'll almost never find someone that has owned a diesel powered boat (that could afford it) purchases a gas powered boat after that unless the boat is much smaller. John -- Message posted via BoatKB.com http://www.boatkb.com/Uwe/Forums.aspx/cruising/200701/1 |
8.1L Crusader Fuel Consumption
thats kinda what I figured, I was hoping to burn less and go faster than what
I have now (34 Silverton Aft Cabin with twin gas 7.4L crusaders) it's painful to fill her up...sometimes over $1000... btw, according to the survey, it does 24.6kts @ 4250rpm (WOT) I'm gonna need a 2nd job to put fuel in her..... Wayne.B wrote: lastly, anyone know what the approximate cruise speed and RPM's are on this boat.... With the correct props cruising RPMs should be in the range of 3200 to 3400 assuming 4400 to 4800 at WOT (Wide Open Throttle). Fuel burn will be in the range of 40 to 50 gallons per hour at cruising RPMs. Speed is harder to predict but 18 to 20 kts seems reasonable. A boat that size and weight should really have diesels. -- Message posted via http://www.boatkb.com |
8.1L Crusader Fuel Consumption
excellent articles...thanx!!!
xorbit wrote: I'm considering the purchase of a 2001 Silverton 410 Sportbridge with twin Gas 8.1L Crusaders (425HP) each [quoted text clipped - 11 lines] THANKS!!! Suggested reading.... http://www.yachtsurvey.com/GasDiesel.htm http://www.yachtsurvey.com/GasNdiesel.htm It may be worth taking some time to read the details contained in these articles. -- Message posted via BoatKB.com http://www.boatkb.com/Uwe/Forums.aspx/cruising/200701/1 |
8.1L Crusader Fuel Consumption
"khessert via BoatKB.com" u30800@uwe wrote in news:6c2ee3d8ce90a@uwe:
I'm gonna need a 2nd job to put fuel in her..... Shoulda got the Trawler. Why do people buy a boat that are in so much of a hurry?! They race from one marina to the other at 30 knots, burning a thousand gallons of fuel at $3 a gallon, or more, for what, to get to the dock first? The trawler, not an overpowered twin screw trawler, a real displacement trawler, goes 8 knots (1/3 the speed of the guzzler) and burns 20 gallons all day at displacement speed. It takes 3 times as long to get there, as you relax cruising along watching the dolphins and waving at the passing people. In the ICW, especially in Florida, it arrives at exactly the same time because the whole damned place is lined with docks and boats and is a no-wake zone the trawler guy doesn't have to worry about. The slow-speed, naturally aspirated, marinized tractor engine in the trawler will run for your lifetime with an occasional oil change and water pump impeller. Noone mentioned in this thread overhauling high performance fast boat engines run so hard. I don't think they'll make 10,000 hours like the Perkins or John Deere or old reliable slow beast that's so simple anyone can fix it, even you. RELAX! Wave at the Crackers sitting on their dock without waking their old boat. That marina will still be there...even next week! We'll anchor the trawler out in some nice creek and have steaks and ale for dinner and watch the alligators, tonight. Don't be in such a hurry! $155K can buy a helluva big, single screw used trawler. Larry -- Extremely intelligent life exists that is so smart they never called Earth. |
8.1L Crusader Fuel Consumption
On Fri, 12 Jan 2007 18:00:55 GMT, "khessert via BoatKB.com"
u30800@uwe wrote: I agree wholeheartedly with diesels being superior, but the gas boat is $155K and the same boat with diesels is $240K its gonna take a long time to burn $85K in fuel... I want the diesels, but it doesn't make sense in this scenario....anybody agree??? It depends. If fuel range is important to you, diesels are the answer. On the other hand, if you can fill up any time you want and the cost is not an issue, your logic makes perfect sense. |
8.1L Crusader Fuel Consumption
khessert via BoatKB.com wrote: I agree wholeheartedly with diesels being superior, but the gas boat is $155K and the same boat with diesels is $240K its gonna take a long time to burn $85K in fuel... I want the diesels, but it doesn't make sense in this scenario....anybody agree??? Capt John wrote: But he's definitely a sceptic [quoted text clipped - 7 lines] condos hardly need an engine that runs at all, just sitting there like most do. One point not looked into is the resale value of a diesel vs a gas powered boat. The diesel is always going to have a better resale. Some points that are hard to quantify are when you have diesel power, the knowledge that it's much more reliable, your just not going to have as many problems, if you maintain them and don't abuse them. The boat will be much more enjoyable with diesels, you've got more power available when, or if, you want it. You can take a boat load of friends on board and it's not going to suddenly slow way down, or not get up on plane. You won't like it when the same boat with diesels fly's on past you. And it's going to be less painful when it comes time to fill the fuel tanks. It's hard to put a price on peace of mind. And I know the price differance is a lot. But if you could have afforded the diesels, and you didn't go for them, you'll find that you will regret not getting them. You'll almost never find someone that has owned a diesel powered boat (that could afford it) purchases a gas powered boat after that unless the boat is much smaller. John -- Message posted via BoatKB.com http://www.boatkb.com/Uwe/Forums.aspx/cruising/200701/1 Yes, you can buy a lot of fuel for $85K, but the resale on the boat will probably get you back about half of that, depending on the engines you get. And the boat will have greater speed and range. Your also not going to have to look at repowering as often with the diesel. It really depends on how you intend to use the boat. If your going short distances, putting low hours on the engines, and speed isn't an issue, gas engines are probably the way to go. But if you intend to run long distances, put lots of hours on the engines, speed is important because of distance needed to travel, and the added reliability is important because help may not be close by, diesels are the way to go. John |
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