25 Tug questions...answered!
- Thread starter New Hampshire Guy
- Start date
Dtol,
You need to go back to the spec sheet on the Volvo Penta D3 series. The 160 weight is 511lbs (bobtail-I believe)--I think you got the KG and lbs mixed up. There is no way there is a 160 hp diesel with a weight of 263 lbs! The 4 BY Yanmar and D3 Penta are comperable engines, with perhaps one exception; I believe that the Yanmar was designed as a marine engine primarly.
The Vovlo is a car engine modified for marine use. Volvo has a long and varied history. There are two facts--the engines are green and parts are expensive--all the rest is open to debate. Generally some of the smaller engines did not have good reputations, but the larger heavier commercial engines did. I have owned mostly the larger commercial Volvo's--and they are excellent engines. One has to be cautious with any of the super light, high speed engines. I discussed these engines with Robert Smith (American Marine--the importer of the Ford Lehman--and one of the gurus of trawler type of engines) over dinner one night. His impression is that the smaller high speed diesels are not going to have the longevity that the traditional slower engines have enjoyed. The old Atlas and Gardner--really slow speed engines (200 to 800 RPM) lasted for decades. The mid speed engines lasted in the 10,000 or so hour range (If cared for)--example Ford, Deere and Perkins which ran at 1800 most of the time. Now we are into a series of engines which turn up close to 4000 RPM. Look at the torque curves of theses engines vs the HP. How long are these high speed engines going to last? I note that many of the "Picinic" type of boats with these light engines are being repowered in only a few years.
If you run these high speed engines conservitatively, they will last very well. If you push them and run them nearly flat out, they will most likely not last. Most boaters do not run their engines much--and more rust out, sieze because of water intrustion etc--than actually wear out up until now.
That may change with the high speed diesels. Running the boat on a plane is like running a truck up hill all of the time, not something which a car engine was designed for.
I gave a lot of thought about if I wanted a diesel "trailerable trawler" which might get up to 20 knots, or the cat which I knew would easily go 30 knots. I choose the cat, based on that need for speed at times. The diesel engines will still be 20 to 30% more effecient than the gas engines--but it will take a long time--if ever, to make up for that increased effeciency.
Incidently Yanmar has an excellent reputation of supporting its engines. I found that in Europe it was very easy to obtain parts for a Yanmar engine that I had on my gen set.
Regards,
You need to go back to the spec sheet on the Volvo Penta D3 series. The 160 weight is 511lbs (bobtail-I believe)--I think you got the KG and lbs mixed up. There is no way there is a 160 hp diesel with a weight of 263 lbs! The 4 BY Yanmar and D3 Penta are comperable engines, with perhaps one exception; I believe that the Yanmar was designed as a marine engine primarly.
The Vovlo is a car engine modified for marine use. Volvo has a long and varied history. There are two facts--the engines are green and parts are expensive--all the rest is open to debate. Generally some of the smaller engines did not have good reputations, but the larger heavier commercial engines did. I have owned mostly the larger commercial Volvo's--and they are excellent engines. One has to be cautious with any of the super light, high speed engines. I discussed these engines with Robert Smith (American Marine--the importer of the Ford Lehman--and one of the gurus of trawler type of engines) over dinner one night. His impression is that the smaller high speed diesels are not going to have the longevity that the traditional slower engines have enjoyed. The old Atlas and Gardner--really slow speed engines (200 to 800 RPM) lasted for decades. The mid speed engines lasted in the 10,000 or so hour range (If cared for)--example Ford, Deere and Perkins which ran at 1800 most of the time. Now we are into a series of engines which turn up close to 4000 RPM. Look at the torque curves of theses engines vs the HP. How long are these high speed engines going to last? I note that many of the "Picinic" type of boats with these light engines are being repowered in only a few years.
If you run these high speed engines conservitatively, they will last very well. If you push them and run them nearly flat out, they will most likely not last. Most boaters do not run their engines much--and more rust out, sieze because of water intrustion etc--than actually wear out up until now.
That may change with the high speed diesels. Running the boat on a plane is like running a truck up hill all of the time, not something which a car engine was designed for.
I gave a lot of thought about if I wanted a diesel "trailerable trawler" which might get up to 20 knots, or the cat which I knew would easily go 30 knots. I choose the cat, based on that need for speed at times. The diesel engines will still be 20 to 30% more effecient than the gas engines--but it will take a long time--if ever, to make up for that increased effeciency.
Incidently Yanmar has an excellent reputation of supporting its engines. I found that in Europe it was very easy to obtain parts for a Yanmar engine that I had on my gen set.
Regards,
Yanmar - Volvo Penta[
list]150 - 160 - 180 - 190 HP
Continous HP@ 3600 rpm 114 hp 155 ??? 137 rpm 188 hp ??
Wt 551 lb 511 lbs
Displacement 122 cu in 146 cu in
Length 37in 42in
Width 29.4 in 25.8 in
Hight 29.1 in 26.4
GPH @ 2000 rpm 1.8gph 1.7 gph 1.9gph 2gph
GPH @ 3000 rpm 4gph 4 gph 4.8gph 4.8gph
GPH @ 3600 rpm 6gph 6.5 gph 7gph 8 gph
Power@3000 rpm 138 mhp 150 mhp 150 mhp 155 mhp
Tork1800 rpms 230 nm 340 nm 230 nm 410 nm
HP at prop ??? 156 hp ??? 182 hp
Data from Manufacturers Charts
[/list]
Well this is what I see:
The way we us our 22 cruiser is usually at speeds between 14 and 18 knots to get to fishing areas. In the bay we deal with wakes all the time which slows us down and on the ocean we feel good if we can make the crossing at 16 knots and really good if we can do it faster. Cruising we follow the pattern of most everybody else and seldom get above 10 knots. We seem to average 3.5 gallons per hour no matter what we are doing.
We would be happy if the CR 25 could get 15 knots economically and without stressing the engine and more if needed. The CR 25 would give us the room and comfort we are looking for with a nice fishing platform in the back and still be able to trailer it.
So the question is how to power the boat so this can be achieved. The 4 engines above certainly have the potential.
1. They all would cruise economically at 2000 RPMs
2. The 180 and 190 HP versions don't seem to have their power advantage until they are approaching their continous RPMs of 3600.
3. I believe that at 3000 RPMs there is little advantage from the larger motors since the horse power is about the same except for the Yanmar 150which is less.
4. At 3000 RPMs the 150/160 engines run more economically than the 180/190s.
5. The question is can these engines move the boat onto plane and travel at least 15 knots at 3000 RPMs.
6. I believe the Volvo Penta 160 has the best chance of doing this economically. It has a tremendous tork advantage at less than 2000 RPMs to better get on plane and its horse power ratings at 3000 RPMs are quite a bit higher than the Yanmar. So it should be able to turn a bigger prop at those RPMs.
7. The factory rated fuel consumption is the same for both at 3000 RPMs
If the factory fuel consumption tables are close to the real world the boat should be able to achieve 18 knots for 6 GPH which is about what the 25 cruiser is using with both the twin 90s and the 150.
Now, not being a professional, I may be in the ozone some where and if I am, I wish someone will tell me nicely and help me make this decision with a more accurate assessment of the available data.
Have a great evening!
dtol
list]150 - 160 - 180 - 190 HP
Continous HP@ 3600 rpm 114 hp 155 ??? 137 rpm 188 hp ??
Wt 551 lb 511 lbs
Displacement 122 cu in 146 cu in
Length 37in 42in
Width 29.4 in 25.8 in
Hight 29.1 in 26.4
GPH @ 2000 rpm 1.8gph 1.7 gph 1.9gph 2gph
GPH @ 3000 rpm 4gph 4 gph 4.8gph 4.8gph
GPH @ 3600 rpm 6gph 6.5 gph 7gph 8 gph
Power@3000 rpm 138 mhp 150 mhp 150 mhp 155 mhp
Tork1800 rpms 230 nm 340 nm 230 nm 410 nm
HP at prop ??? 156 hp ??? 182 hp
Data from Manufacturers Charts
[/list]
Well this is what I see:
The way we us our 22 cruiser is usually at speeds between 14 and 18 knots to get to fishing areas. In the bay we deal with wakes all the time which slows us down and on the ocean we feel good if we can make the crossing at 16 knots and really good if we can do it faster. Cruising we follow the pattern of most everybody else and seldom get above 10 knots. We seem to average 3.5 gallons per hour no matter what we are doing.
We would be happy if the CR 25 could get 15 knots economically and without stressing the engine and more if needed. The CR 25 would give us the room and comfort we are looking for with a nice fishing platform in the back and still be able to trailer it.
So the question is how to power the boat so this can be achieved. The 4 engines above certainly have the potential.
1. They all would cruise economically at 2000 RPMs
2. The 180 and 190 HP versions don't seem to have their power advantage until they are approaching their continous RPMs of 3600.
3. I believe that at 3000 RPMs there is little advantage from the larger motors since the horse power is about the same except for the Yanmar 150which is less.
4. At 3000 RPMs the 150/160 engines run more economically than the 180/190s.
5. The question is can these engines move the boat onto plane and travel at least 15 knots at 3000 RPMs.
6. I believe the Volvo Penta 160 has the best chance of doing this economically. It has a tremendous tork advantage at less than 2000 RPMs to better get on plane and its horse power ratings at 3000 RPMs are quite a bit higher than the Yanmar. So it should be able to turn a bigger prop at those RPMs.
7. The factory rated fuel consumption is the same for both at 3000 RPMs
If the factory fuel consumption tables are close to the real world the boat should be able to achieve 18 knots for 6 GPH which is about what the 25 cruiser is using with both the twin 90s and the 150.
Now, not being a professional, I may be in the ozone some where and if I am, I wish someone will tell me nicely and help me make this decision with a more accurate assessment of the available data.
Have a great evening!
dtol
Vikingbaat
New member
Les:
1. If one opts for the Yanmar 110HP engine, what kind of performance can one expect?
2. If the factory offers the Volvo 160HP engine as an option, can you offer a guess as to the cost for the Volvo upgrade?
R-25 on order
1. If one opts for the Yanmar 110HP engine, what kind of performance can one expect?
2. If the factory offers the Volvo 160HP engine as an option, can you offer a guess as to the cost for the Volvo upgrade?
R-25 on order
Pat Anderson
New member
Yes, basically most of Les has been saying was confirmed by Jeff at the Lake Union Boats Afloat Show yesterday- we made a last minute decision to try to get there for the last hour yesterday. The boat is GORGEOUS, it will be worth the wait - and if you don't mind 7 - 10 knot cruising, it is ready now. But you are not going to get the promised 16 knot cruise until they solve the engine dilemma. The performance reports vary only slightly, and that could be due to current, wind, and load - neither Jeff nor Les got performance ANYTHING like what Y-Landing John reported above. Jeff got 13 knots top speed. He also confirmed that they are scrambling to get the Volvo D3 engines in for tests. We certainly are going to wait for a Volvo engine before we take the plunge, as the boat cannot currently deliver the advertised perfomance promised at the 2006 SBS.
oldgrowth":7ev1j2m1 said:
The old addage of one gallon of diesel an hour for 20 hp is still fairly close for the new high speed diesels. Thus if you are truely using 160 hp, you will burn 8 gal an hour. You don't want to run the boat on the "hump" of the curve, where the boat is not really on a plane, because this is not fuel effecient, and tends to lug the engine. Although you have torque at low HP, my experience in V hulls leads me to believe that you will have to bring engine speed up above 3000 to get on a plane, and will still be well over the 1800 RPM range when on a plane. The high torque at lower RPM works well for the displacement mode. The C Dory, being a flat bottom boat, will semi plane--at a low speed. This allows reasonable fuel consumption and being able to handle rough water at a slower speed. Since the hull form of the C R 25 is more of a traditional shallow V, it will probably behave more like this type--and until we see some rough water real life numbers, we will not know how much fuel the boat will use in these conditions.
When I made the decision to buy the Tom Cat, I was aware that going into the waves over 3 feet, I would be at a disadvantage in comparison to some other cats--but the other features won the day. So all boats remain compromises and you must decide what your priorities are. Don't feel too pressured into your decision until you see what happens with other engines. The Camano (really 28 feet and 10,000 lbs) is advertised as a planing boat with 200 hp, but I have several friends who own them, and their conclusion is that they were best at dispalcement speeds.
When I made the decision to buy the Tom Cat, I was aware that going into the waves over 3 feet, I would be at a disadvantage in comparison to some other cats--but the other features won the day. So all boats remain compromises and you must decide what your priorities are. Don't feel too pressured into your decision until you see what happens with other engines. The Camano (really 28 feet and 10,000 lbs) is advertised as a planing boat with 200 hp, but I have several friends who own them, and their conclusion is that they were best at dispalcement speeds.
Les Lampman
New member
Vikingbaat":1unzsy8f said:
I'm going to stick with my 9,000 pound fully-loaded (with full liquids, gear, and crew) for the following:
It takes 112 horsepower to push a 9,000# boat of this hull style to 15 knots in CALM conditions. That pretty much tells you where the 110hp version stands. Keep in mind neither Jeff nor I (on separate occasions) got more than around 13 knots at WOT from the 125; I'm sure there were extenuating circumstances pertaining to hull #1 but it still gives us an idea of what the boat will require.
Remember too that we've not been able to get a loaded boat up in the target speed range. Depending on how the boat is loaded (weight and balance), sea conditions and such it may be that a higher speed than 15 knots will actually be the ticket; that's just at the speed-length ratio of 3 which puts in on a plane but perhaps barely. It may turn out that running 16 to 18 knots is actually more comfortable, offers better visibility and a better running attitude. In that case I think an engine like the Volvo D3 190hp version would be the best choice allowing for some reserve horsepower (but that remains to be seen and it may be that the 160 works fine).
Pricing seems to be hard to come by and I don't have any specific information. In general I seem to find the Yanmar 100 to be in the mid teens with gearbox, the 125 a couple of grand more, and the 200 just under $20K. On the European sites the D3-160 seems to run around 13,000 pounds; doing a straight pounds-to-dollar translation doesn't work...we don't pay that much here. It does seem based on products I do know that adding about 25% in dollars to the listed pounds generally comes close. The 190 version looks to be maybe $3K more.
After all that I have no idea what it means!
How it falls through to the bottom line is an unknown as it really depends on which engine ends up being the choice and what sort of pricing C-Dory can get on the engines. The Volvo Penta distributor may have a totally different program available than the Yamnar folks...good or bad.It does seem the price of admission to high-speed cruising (that's a relative term!) is not cheap. The 55hp engine is in the $10K price range and the Yanmar 190hp about $20K so there's a $10K premium for the engine to start with. Robert Beebe's rule-of-thumb in Voyaging Under Power for fuel consumption was .06 gph per (1) horsepower; modern electronic engines are doing better and usually are figured at .055 gph/hp. We need about 25 horspower to cruise the CR25 at 7.5 knots and that gives a fuel burn of 1.3 to 1.4 gph or just over 5 nmpg (as an aside 6.5 knots requires 15 horsepower with a fuel burn of .8 gph yielding 8 nmpg with a range of 600 nm although the slower you go the less likely it is you'll hit the numbers as current, wind and sea state become an ever increasing percentage of the total). At 18 knots the boat requires about 130 hp which has a fuel burn of about 7 gph or 2.5 nmpg. The fine print...without testing in specific conditions with known values these are just estimates but I've tried to make them as realistic as possible. As a general rule-of-thumb to go two times faster requires four times more power.
Vikingbaat
New member
Les, thataway, and Pat: thanks for the great info.
I put money down on an R-25 at the 2006 Seattle boat show. The internet literature assumes an 80HP (really75HP) Yanmar as standard and an additional, I believe, $3750 for the 110HP option. If the factory still assumes the 75HP Yanmar is the basic engine, then to purchase the Volvo 160, etc. (If it is an option) could get expensive. I hope that in light of the reduced performance of the 110HP Yanmar, the factory will consider, at least, this as the basic engine offered.
R-25 on order
I put money down on an R-25 at the 2006 Seattle boat show. The internet literature assumes an 80HP (really75HP) Yanmar as standard and an additional, I believe, $3750 for the 110HP option. If the factory still assumes the 75HP Yanmar is the basic engine, then to purchase the Volvo 160, etc. (If it is an option) could get expensive. I hope that in light of the reduced performance of the 110HP Yanmar, the factory will consider, at least, this as the basic engine offered.
R-25 on order
Les Lampman
New member
Here's a bit of info for comparison:
Top speeds for a 9,000 boat:
55 hp = 9.5 knots
75 hp = 10.2 knots
100 hp = 11.5 knots
---transition to planning---
110 hp = 16 knots
125 hp = 17.5 knots
140 hp = 20 knots
160 hp = 21.25 knots
180 hp = 22.5 knots
Top speeds for a boat equipped with a 110hp engine at various weights:
9000# = 16 knots
8500# = 17 knots
8000# = 18.5 knots
7500# = 19.5 knots
7000# = 20.5 knots
These are wide open throttle speeds assuming the engine turns up to full rated horsepower in calm conditions.
You can see what weight does here quite dramatically. The 110hp engine is on the cusp; if the hull doesn't quite transition to planning it's not going to get the speeds above. Even the 125 didn't quite do it on hull #1 but until I run a production hull at finalized weight I won't really know where the exact break point is. Also the boat has a fair amount of windage with large front vertical windows and a tall cabin structure so it's not the same as running a sleek runabout and wind will definately affect it.
My take so far (subject to change with more data) is to either go with a smaller engine for slower operation, less upfront money and better mileage or get an engine large enough to reliably get the hull "on top" with real world loads aboard so that it runs efficiently and comfortably. For now that looks to be something in the continuous hp range of 140 hp.
Have a good weekend.
Top speeds for a 9,000 boat:
55 hp = 9.5 knots
75 hp = 10.2 knots
100 hp = 11.5 knots
---transition to planning---
110 hp = 16 knots
125 hp = 17.5 knots
140 hp = 20 knots
160 hp = 21.25 knots
180 hp = 22.5 knots
Top speeds for a boat equipped with a 110hp engine at various weights:
9000# = 16 knots
8500# = 17 knots
8000# = 18.5 knots
7500# = 19.5 knots
7000# = 20.5 knots
These are wide open throttle speeds assuming the engine turns up to full rated horsepower in calm conditions.
You can see what weight does here quite dramatically. The 110hp engine is on the cusp; if the hull doesn't quite transition to planning it's not going to get the speeds above. Even the 125 didn't quite do it on hull #1 but until I run a production hull at finalized weight I won't really know where the exact break point is. Also the boat has a fair amount of windage with large front vertical windows and a tall cabin structure so it's not the same as running a sleek runabout and wind will definately affect it.
My take so far (subject to change with more data) is to either go with a smaller engine for slower operation, less upfront money and better mileage or get an engine large enough to reliably get the hull "on top" with real world loads aboard so that it runs efficiently and comfortably. For now that looks to be something in the continuous hp range of 140 hp.
Have a good weekend.
Les
Do you think that they will ever be able to produce the CR25 at the production weight of 5400lbs or even <6000lbs that they originally projected?? I am not sure what they would have to give up in the design and options to do it.
Are they looking at weight management at all in reworking this whole formula or is power the only componant they are thinking about.
Do you think that they will ever be able to produce the CR25 at the production weight of 5400lbs or even <6000lbs that they originally projected?? I am not sure what they would have to give up in the design and options to do it.
Are they looking at weight management at all in reworking this whole formula or is power the only componant they are thinking about.
Thanks for the information on HP and speed.
Here is a question. I understand that the numbers you gave were based on 3600 turns per minute on the propeller. The Volvo D3 160 produces 150 horses at 3000 rpm. The Yanmar 180 is the same at 3000 and the Volvo 190 produces 155 horses at 3000 rpm. Is there a way to figure how these speed numbers change to see the speed at 3000 RPM??
If these engines are capable of producing 150 horses at 3000 rpms couldn't you conpensate for lower RPMs with a larger propeller and fine tune the boat to run more effeciently at 3000 RPMs
Sorry if these are dumb questions. My logic takes me places that are not supported with technical knowlege.
Here is a question. I understand that the numbers you gave were based on 3600 turns per minute on the propeller. The Volvo D3 160 produces 150 horses at 3000 rpm. The Yanmar 180 is the same at 3000 and the Volvo 190 produces 155 horses at 3000 rpm. Is there a way to figure how these speed numbers change to see the speed at 3000 RPM??
If these engines are capable of producing 150 horses at 3000 rpms couldn't you conpensate for lower RPMs with a larger propeller and fine tune the boat to run more effeciently at 3000 RPMs
Sorry if these are dumb questions. My logic takes me places that are not supported with technical knowlege.
EQ is closed until Tuesday a.m. - so here's my take (frightening, eh?). Les's numbers are based on HP not on RPM. With the data provided by various engine manufacturers it's a simple calculation to determine HP approximations for various engine rpm's. The RPM vs boat speed estimates are NEVER real world numbers - just too many variables.
Les and I have talked a lot about reducing weight for the C-Ranger 25 - but these are questions only the manufacturer can answer. All of my boat testing has shown the same relative speed decrease with added weight. Not magic at all, just basic formulas used by naval architects and proved time and again from practical application.
The C-Ranger 25 is a beautiful boat, and IMO it will be a major player in the pocket cruiser market. The gestation of a new model is always difficult, from my own experience, and I think they will end up with a real jewel. Patience, friends.
Dusty
Les and I have talked a lot about reducing weight for the C-Ranger 25 - but these are questions only the manufacturer can answer. All of my boat testing has shown the same relative speed decrease with added weight. Not magic at all, just basic formulas used by naval architects and proved time and again from practical application.
The C-Ranger 25 is a beautiful boat, and IMO it will be a major player in the pocket cruiser market. The gestation of a new model is always difficult, from my own experience, and I think they will end up with a real jewel. Patience, friends.
Dusty
Dtol, you have to understand that thrust at the prop is what is important.
The 75 hp engine comes with a reduction ratio of 1.47 to 3.3 and the 125 hp Yanmar comes with 1.73 to 2.48. I don't know what transmission is on the individual boats or what prop is on the boats. The diameter and pitch of the prop is important. The boat is proped to achieve max RPM of each of these engines--and no more. So that speed of the prop shaft turning is not relevant--only the amount of thrust that the prop generates. Even with inboard diesel boats, expermentation on the props is often necessary to achieve the best effeicency or speed. (and they may not be the same prop). If you are only going to run the boat at 8 knots, you would put a different transmission and prop than if you were trying to achieve 20 knots. At least in sailboats (where most of my experience lies) many boats are not proped correctly from the factory. (I actually changed the props twice a week, in the water, at one point in my life, going from racing to cruising mode) Trawlers are usually close, but not necessarilly on the first boats.
Les mentioned "Voyaging Under Power" (I have both the origional 1st edition and the most recent addition) which is an excellent book to study if you don't already own it. Again I am going to suggest that you get David Gerr's "The Nature of Boats"--probably cost about $70 total for the two books, and money well spent to have a better understanding of hulls, props, effeciency etc.
The 75 hp engine comes with a reduction ratio of 1.47 to 3.3 and the 125 hp Yanmar comes with 1.73 to 2.48. I don't know what transmission is on the individual boats or what prop is on the boats. The diameter and pitch of the prop is important. The boat is proped to achieve max RPM of each of these engines--and no more. So that speed of the prop shaft turning is not relevant--only the amount of thrust that the prop generates. Even with inboard diesel boats, expermentation on the props is often necessary to achieve the best effeicency or speed. (and they may not be the same prop). If you are only going to run the boat at 8 knots, you would put a different transmission and prop than if you were trying to achieve 20 knots. At least in sailboats (where most of my experience lies) many boats are not proped correctly from the factory. (I actually changed the props twice a week, in the water, at one point in my life, going from racing to cruising mode) Trawlers are usually close, but not necessarilly on the first boats.
Les mentioned "Voyaging Under Power" (I have both the origional 1st edition and the most recent addition) which is an excellent book to study if you don't already own it. Again I am going to suggest that you get David Gerr's "The Nature of Boats"--probably cost about $70 total for the two books, and money well spent to have a better understanding of hulls, props, effeciency etc.
Bob,
Sure do agree on the library. Have all three, and all are good reading for a layman... Gerr is great. I have many more technical books, but his are easy reads and cover everything most of us want/need to know in understandable language. Unfortunately, all of my sailing was without power! Part of my purchase agreement - and I was watched carefully by the previous owner!
Dusty
Sure do agree on the library. Have all three, and all are good reading for a layman... Gerr is great. I have many more technical books, but his are easy reads and cover everything most of us want/need to know in understandable language. Unfortunately, all of my sailing was without power! Part of my purchase agreement - and I was watched carefully by the previous owner!
Dusty
Pat Anderson
New member
OK, I know we will have to wait to see what develops of course, and we want to get out on both a C-Ranger 25 with the 110 Yanmar and one of the Volvo Penta D3s to really see how it feels, but I have read and re-read Les's description of his experience and his thoughts on powering this boat, and am trying to understand that "not particularly happy in-between" part, and what implications are for what would actually make us happy, since whatever choice we make we will have to live with for a long time.
I gather Les means with the hull characteristics of this boat we want to run at 7.5 knots or below or 12.5 knots or above...We definitely do not want to be limited to Dusty's 7.5 knot cruise, we would perceive that as a big step backwards from our CD25, so the 55 - 80 hp Yanmars, are definitely out. Seems we need to get to or above 12.5 knots to get the bow down. It looks like the 110 - 125 hp Yanmars can't reliably deliver that running in the 75% range, we sure don't want to be running WOT to achieve a 12.5 knot cruise in calm waters.
But we don't need a 16 knot cruise and 19 knot top speed - we would be very happy with a 12.5 - 13 knot cruise speed with the bow down (out of that "in-between" range) and the engine having enough reserve to deal with wind and current. So if the Volvo Penta D3 150 (or is it 160?) has that "few more knots" to achieve that, that would seem ideal. So what do we see as economy in that scenario from our formulae, assuming the 9,000 lbs is right (since it only gets better if Dave can shed a bunch of weight from there) and cruising at say 12.5 knots? Or are the characteristics of the Volvo not suited for this scenario?
I gather Les means with the hull characteristics of this boat we want to run at 7.5 knots or below or 12.5 knots or above...We definitely do not want to be limited to Dusty's 7.5 knot cruise, we would perceive that as a big step backwards from our CD25, so the 55 - 80 hp Yanmars, are definitely out. Seems we need to get to or above 12.5 knots to get the bow down. It looks like the 110 - 125 hp Yanmars can't reliably deliver that running in the 75% range, we sure don't want to be running WOT to achieve a 12.5 knot cruise in calm waters.
But we don't need a 16 knot cruise and 19 knot top speed - we would be very happy with a 12.5 - 13 knot cruise speed with the bow down (out of that "in-between" range) and the engine having enough reserve to deal with wind and current. So if the Volvo Penta D3 150 (or is it 160?) has that "few more knots" to achieve that, that would seem ideal. So what do we see as economy in that scenario from our formulae, assuming the 9,000 lbs is right (since it only gets better if Dave can shed a bunch of weight from there) and cruising at say 12.5 knots? Or are the characteristics of the Volvo not suited for this scenario?
Les Lampman":wq6pstmy said:
I believe this thread has helped keep me from making a major mistake. I was ready to jump last friday but didn't. Some very good people have shared their time and knowledge to answer questions and provide information in a most accurate and timely way.
The original Rangers share the typical design of the slow cruise economical boat intended to slow cruise 12 hours on 5 gallons of fuel or less. The question isn't how big of a motor you can put on these boats, but, how small of a motor and still cruise at 6 to 8 knots. These boats do this extremely well.
It appears that the goal with the design of the C-Ranger 25 is to build a larger boat at around 5500lbs dry and 7000lbs loaded with the luxuries and speed in demand by the public which is still in the tradition of the Ranger 21s. And provide it to the customer in an almost turn key ready to go condition which doesn't require the months of fabrication needed to put the amenities desired by the new owner.
The design would require a weight to power ratio that would allow the slow cruise capability and provide the 6 to 8 knot effeciency and give 14 to 18 knots effeciently on plane using about 50 gallons to cruise 12 hours . This would be unique in the industry and certainly caught the eye of the boating public. It certainly did me. I've been going nuts this last few days.
The current tests indicate that the first boats were not fully on plane at 13 knots which was the maximum speed they were able to acheive not fully loaded with the 125hp Yanmar.
The result is an overweight boat that will need a large engine and will use between 80 and 100 gallons to cruise 12 hours on plane. This is no different than all the other big boats out there. So, except for the layout and standard options and the price which is very high, it isn't much different from any other big heavy boat.
I've been looking at the Nordic Tug 37 and it will cruise at 8 knots forever at 3 gallons an hour, but needs about 10 to 12 gallons an hour to go 16 knots. It weighs 22000lbs though. You can get a Nordic Tug 32ft at about $50K more than what this 24ft will cost. Its going to be $160K+ to get a C-Ranger 25. To be economical, the Nordic Tug is a slow cruiser and it can't be trailered.
I would say that if you can live with 6 to 8 knots and need speed and be on plane only occasionally then the C-Ranger 25, at its present weight would be good for you and an economical boat.
As for me, my fishing to pleasure cruising ratio is about 1/3, 2/3s A typical run on a typical fishing day is between 50 and 80 miles for a round trip which, hopefully can be done done at 14 knots or above to maximize fishing time. I would be happy if 15 knots could be achieved below WOT and at 4 to 5 GPH. This becomes an expensive boat to run in its present configuration. I guess I am spoiled by my 22 Cruiser which does the 80 miles on 18 gallons of gas consistently as hard as conditions will let me go and under 5000 rpms. Hopefully at 21 miles an hour loaded. Its so easy to trailer. I was willing to reduce my expectations for speed for the C-Ranger 25.
It seems to me that the Ranger folks, in order to have the unique product originally envisioned, need to focus on weight, not larger engines.
What happened to the balsa core technology used on the original C-Dory boats? It appears that the C-Ranger makes extensive use of heavy plywood.
The original Rangers share the typical design of the slow cruise economical boat intended to slow cruise 12 hours on 5 gallons of fuel or less. The question isn't how big of a motor you can put on these boats, but, how small of a motor and still cruise at 6 to 8 knots. These boats do this extremely well.
It appears that the goal with the design of the C-Ranger 25 is to build a larger boat at around 5500lbs dry and 7000lbs loaded with the luxuries and speed in demand by the public which is still in the tradition of the Ranger 21s. And provide it to the customer in an almost turn key ready to go condition which doesn't require the months of fabrication needed to put the amenities desired by the new owner.
The design would require a weight to power ratio that would allow the slow cruise capability and provide the 6 to 8 knot effeciency and give 14 to 18 knots effeciently on plane using about 50 gallons to cruise 12 hours . This would be unique in the industry and certainly caught the eye of the boating public. It certainly did me. I've been going nuts this last few days.
The current tests indicate that the first boats were not fully on plane at 13 knots which was the maximum speed they were able to acheive not fully loaded with the 125hp Yanmar.
The result is an overweight boat that will need a large engine and will use between 80 and 100 gallons to cruise 12 hours on plane. This is no different than all the other big boats out there. So, except for the layout and standard options and the price which is very high, it isn't much different from any other big heavy boat.
I've been looking at the Nordic Tug 37 and it will cruise at 8 knots forever at 3 gallons an hour, but needs about 10 to 12 gallons an hour to go 16 knots. It weighs 22000lbs though. You can get a Nordic Tug 32ft at about $50K more than what this 24ft will cost. Its going to be $160K+ to get a C-Ranger 25. To be economical, the Nordic Tug is a slow cruiser and it can't be trailered.
I would say that if you can live with 6 to 8 knots and need speed and be on plane only occasionally then the C-Ranger 25, at its present weight would be good for you and an economical boat.
As for me, my fishing to pleasure cruising ratio is about 1/3, 2/3s A typical run on a typical fishing day is between 50 and 80 miles for a round trip which, hopefully can be done done at 14 knots or above to maximize fishing time. I would be happy if 15 knots could be achieved below WOT and at 4 to 5 GPH. This becomes an expensive boat to run in its present configuration. I guess I am spoiled by my 22 Cruiser which does the 80 miles on 18 gallons of gas consistently as hard as conditions will let me go and under 5000 rpms. Hopefully at 21 miles an hour loaded. Its so easy to trailer. I was willing to reduce my expectations for speed for the C-Ranger 25.
It seems to me that the Ranger folks, in order to have the unique product originally envisioned, need to focus on weight, not larger engines.
What happened to the balsa core technology used on the original C-Dory boats? It appears that the C-Ranger makes extensive use of heavy plywood.
Pat,
Yes, you have the area from about 1.3 x sq rt LWL to 2.8x sq Rt LWL, which is fast semi displacement and not on a plane. There are boats designed to do this. The New England Lobster boat is such a type of design. These have flat runs aft, but with soft rounded chines. Usually quite fine foreward. There are some hulls which are designs to sort of "trick" the water flow, and get a little more effeciency in these ranges. But not many successful production boats which do this.
Dtol,
There are other types of boats which will do what you want--and the cats are where this is mostly--but none are super effecient that I have seen so far. Also very few are within the 8' 6" width for legal trailering without a permit. Maybe the C Dory 25 is not a bad boat after all for your type of use? New engines are slightly more effecient.
When we were cruising Alaska, we ran into several folks who were renting the Tug Trawlers out of the Juneau area--looking at putting bigger engines into them for the planing speeds. I thought it was a bit foolish at the time, and I still do, but most of them are sold with the large engines.
There are other boats semidisplacement boats, such as the Duffy, Cape Dory, Rosobrough, Camano which all can be purchased with diesels. But they all have the same type of characteristics. Not as effecent as a real planing boat, once on a plane. Same is true with the Tom Cat--it appears that in the narrow planing range, that the Tom Cat is more effecient than the World Cat and Glacier Bay--but not necessarilly so at the speed when the Tom Cat is off the plane.
I also follow the Rosoborough threads, and they power the boats from 50 hp on up to twin 150's--the diesels are mostly in the 150 to 160 range-both I/O and inboard. They have the same issues as the C Ranger.
Dusty:
I'll bet we have the same techinical books also. I had power in my long range cruising boats--but did a lot of small boat racing with no power also.
All of this messing around in boats is fun...not back to work.
Yes, you have the area from about 1.3 x sq rt LWL to 2.8x sq Rt LWL, which is fast semi displacement and not on a plane. There are boats designed to do this. The New England Lobster boat is such a type of design. These have flat runs aft, but with soft rounded chines. Usually quite fine foreward. There are some hulls which are designs to sort of "trick" the water flow, and get a little more effeciency in these ranges. But not many successful production boats which do this.
Dtol,
There are other types of boats which will do what you want--and the cats are where this is mostly--but none are super effecient that I have seen so far. Also very few are within the 8' 6" width for legal trailering without a permit. Maybe the C Dory 25 is not a bad boat after all for your type of use? New engines are slightly more effecient.
When we were cruising Alaska, we ran into several folks who were renting the Tug Trawlers out of the Juneau area--looking at putting bigger engines into them for the planing speeds. I thought it was a bit foolish at the time, and I still do, but most of them are sold with the large engines.
There are other boats semidisplacement boats, such as the Duffy, Cape Dory, Rosobrough, Camano which all can be purchased with diesels. But they all have the same type of characteristics. Not as effecent as a real planing boat, once on a plane. Same is true with the Tom Cat--it appears that in the narrow planing range, that the Tom Cat is more effecient than the World Cat and Glacier Bay--but not necessarilly so at the speed when the Tom Cat is off the plane.
I also follow the Rosoborough threads, and they power the boats from 50 hp on up to twin 150's--the diesels are mostly in the 150 to 160 range-both I/O and inboard. They have the same issues as the C Ranger.
Dusty:
I'll bet we have the same techinical books also. I had power in my long range cruising boats--but did a lot of small boat racing with no power also.
All of this messing around in boats is fun...not back to work.
Bob
You might be right on track with the CD 25 for me.
I was still hoping to compromise some on speed (15-16 knots medium cruise and below WOT as apposed to 18-20 knots expensive running at WOT) to get the comfort and amenities for pleasure cruising. May not happen though. I,ll wait and see what they do with weight. Could get a Sea Sport for a whole lot less money if I wanted an overweight fuel hog. Just for grins, I wonder how the C-ranger would perform with the CD-25 hull under it.
The Nordic Tug has the same type of hull as the CR-25 and is built entirely for pleasure cruising.
You might be right on track with the CD 25 for me.
I was still hoping to compromise some on speed (15-16 knots medium cruise and below WOT as apposed to 18-20 knots expensive running at WOT) to get the comfort and amenities for pleasure cruising. May not happen though. I,ll wait and see what they do with weight. Could get a Sea Sport for a whole lot less money if I wanted an overweight fuel hog. Just for grins, I wonder how the C-ranger would perform with the CD-25 hull under it.
The Nordic Tug has the same type of hull as the CR-25 and is built entirely for pleasure cruising.
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