I currently have a 5hp motor on my Catalina 22. I generally make just over 5 knots while motoring depending upon wind, current, tide, etc. I am wondering how much speed a might get out of a larger motor and what some of the tradeoffs would be (penalty for the extra weight while sailing for instance) of using a larger motor. The manual suggests 4 - 6 hp. My understanding is that the hull speed for this boat is just under 6 knots, so it would seem that more horsepower would have more drawbacks than benefits, but since I have to motor about two miles up a creek to get to sailing territory, I'm wondering is something more like 8 hp would get be out sailing sooner. Thanks in advance for your replies and comments.
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K
ken
outboard
JR.............. Wow..... you have to motor 2 miles to hoist the sails?? That's alot! I have an 8 HP Nissan and it will push the boat along at about 5-6 knots. You ain't gonna go any faster if you had a 25 hp on your boat! You have a 5 HP......... it works OK......spend your $$ on something else. You are in good shape!
JR.............. Wow..... you have to motor 2 miles to hoist the sails?? That's alot! I have an 8 HP Nissan and it will push the boat along at about 5-6 knots. You ain't gonna go any faster if you had a 25 hp on your boat! You have a 5 HP......... it works OK......spend your $$ on something else. You are in good shape!
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Joe
Not worth it.
I would think that anything over 6 is unnecessary. If you are only motoring 2 miles, the difference in time you save would be less than 5 minutes. (2/6 x 60 = 20 min. vs 2/5 x 60 = 24 min.) Since you are only concerned with speed through the water, tide and current would not be a factor when considering a power upgrade. If, on the other hand, you must motor long distance through waves, chop and headwind, more power might be justified to maintain speed through the water, but that speed will still be held to under 6 kts. One more thought. If your prop cavitates at high rpm and the boat is still not reaching hull speed, you might consider going to a lower pitch prop. This might let you tap that upper power band on the motor by switching gears, so to speak.
I would think that anything over 6 is unnecessary. If you are only motoring 2 miles, the difference in time you save would be less than 5 minutes. (2/6 x 60 = 20 min. vs 2/5 x 60 = 24 min.) Since you are only concerned with speed through the water, tide and current would not be a factor when considering a power upgrade. If, on the other hand, you must motor long distance through waves, chop and headwind, more power might be justified to maintain speed through the water, but that speed will still be held to under 6 kts. One more thought. If your prop cavitates at high rpm and the boat is still not reaching hull speed, you might consider going to a lower pitch prop. This might let you tap that upper power band on the motor by switching gears, so to speak.
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tomD
Nissan 6 hp
I have a 4 stroke long shaft 6 hp Nissan because it is relatively light: 68 lbs--doesn't affect the boat as much under sail, plenty of power. 3/4 throttle does 5.5 knots, easy on the motor mount, economical, easy to get along with--you can lift it off no problem. I really think it's all you'd ever need, could likely do it on a 4 hp if you weren't counting on it getting you home on power in very high winds--external tank is a blessing too.
I have a 4 stroke long shaft 6 hp Nissan because it is relatively light: 68 lbs--doesn't affect the boat as much under sail, plenty of power. 3/4 throttle does 5.5 knots, easy on the motor mount, economical, easy to get along with--you can lift it off no problem. I really think it's all you'd ever need, could likely do it on a 4 hp if you weren't counting on it getting you home on power in very high winds--external tank is a blessing too.
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Scot
Why does current make a difference?
I have a 4 hp Suzuki 2-stroke that, at full throttle, pushes my boat at about 6.5 mph according to the GPS. If I understand everyone correctly, a larger motor would not result in any significant increase in that top speed. Every time I've seen outboard horsepower discussed, people always say that a 4-6 hp motor is fine unless you are dealing with current, waves, or wind. This may be a stupid question, but what difference does it make whether you are in a current or in still water? Your maximum speed relative to the water is approximately hull speed, regardless of whether you have 4 hp or 8 hp. I have the same question with regard to waves. As long as your shaft is long enough to keep the prop in the water, what difference does the extra horsepower make? I suppose it could help with maintaining headway up the face of large waves, but that would have to be larger waves than most small boat sailors encounter. I can see where horsepower could be effective in countering a headwind, since hull speed is not a controlling factor. How much wind would it take before a boat with a smaller motor would be having trouble? Sorry if I'm way off base here. I'm an inland lake sailor, so I don't have much experience of currents or waves. One of these days I'll head over to the coast, and I'd like to understand whether my boat is really as underpowered as the conventional wisdom seems to think.
I have a 4 hp Suzuki 2-stroke that, at full throttle, pushes my boat at about 6.5 mph according to the GPS. If I understand everyone correctly, a larger motor would not result in any significant increase in that top speed. Every time I've seen outboard horsepower discussed, people always say that a 4-6 hp motor is fine unless you are dealing with current, waves, or wind. This may be a stupid question, but what difference does it make whether you are in a current or in still water? Your maximum speed relative to the water is approximately hull speed, regardless of whether you have 4 hp or 8 hp. I have the same question with regard to waves. As long as your shaft is long enough to keep the prop in the water, what difference does the extra horsepower make? I suppose it could help with maintaining headway up the face of large waves, but that would have to be larger waves than most small boat sailors encounter. I can see where horsepower could be effective in countering a headwind, since hull speed is not a controlling factor. How much wind would it take before a boat with a smaller motor would be having trouble? Sorry if I'm way off base here. I'm an inland lake sailor, so I don't have much experience of currents or waves. One of these days I'll head over to the coast, and I'd like to understand whether my boat is really as underpowered as the conventional wisdom seems to think.
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Dan
Current events.
Scot, if you are fighting a two knot current on your nose, and your boat is making five knots through the water, your boat is only making three knots over ground. In higher speed currents, fuel consumption and just making headway become issues.
Scot, if you are fighting a two knot current on your nose, and your boat is making five knots through the water, your boat is only making three knots over ground. In higher speed currents, fuel consumption and just making headway become issues.
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Scot
Fuel ok, but headway?
Okay, fuel consumption is something I hadn't considered. Maybe an 8 hp motor will put the boat at hull speed at 1/2 throttle while a 4 hp motor would have to be at near full throttle. Maybe the 8 hp burns less fuel at 1/2 than the 4 hp does at full. However, I still can't see how a boat doing hull speed with 8 hp will do better than one doing hull speed with 4 hp. The current vector is going to do the same thing to both boats, making it just as hard to make headway in either one. Headway against a current is a function of speed through water, not available horsepower. Are you saying that the larger motor really can move the boat significantly above hull speed?
Okay, fuel consumption is something I hadn't considered. Maybe an 8 hp motor will put the boat at hull speed at 1/2 throttle while a 4 hp motor would have to be at near full throttle. Maybe the 8 hp burns less fuel at 1/2 than the 4 hp does at full. However, I still can't see how a boat doing hull speed with 8 hp will do better than one doing hull speed with 4 hp. The current vector is going to do the same thing to both boats, making it just as hard to make headway in either one. Headway against a current is a function of speed through water, not available horsepower. Are you saying that the larger motor really can move the boat significantly above hull speed?
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Joe
Scot... what is your point?
Current doesn't affect hull speed.... you are right. That was stated in my earlier post in this thread..... No one said that the larger motor would move the boat above hull speed. What you fail to understand is that waves and wind are forces separate from flowing water (current). These forces act to PREVENT the boat from attaining hull speed. It was my suggestion that the additional power made available by a stronger motor or a different prop setup (i.e lower gear ratio) might offset some of these forces. Please re-read my previous post.
Current doesn't affect hull speed.... you are right. That was stated in my earlier post in this thread..... No one said that the larger motor would move the boat above hull speed. What you fail to understand is that waves and wind are forces separate from flowing water (current). These forces act to PREVENT the boat from attaining hull speed. It was my suggestion that the additional power made available by a stronger motor or a different prop setup (i.e lower gear ratio) might offset some of these forces. Please re-read my previous post.
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Scot
It's a question, not a point.
Joe, sorry if it sounded like I was ignoring your previous answer. I read it carefully the first time, but yours is not the only opinion I've had on the subject. Dan's post indicated that horsepower might have a bearing on making headway against a current. I'm just trying to resolve something that has been a long-standing question. The points made about wind and fuel consumption are things I hadn't fully considered before. I appreciate having them pointed out. The effect of waves is something I'm still a little unclear about, but I'll save the question rather than annoying anyone further.
Joe, sorry if it sounded like I was ignoring your previous answer. I read it carefully the first time, but yours is not the only opinion I've had on the subject. Dan's post indicated that horsepower might have a bearing on making headway against a current. I'm just trying to resolve something that has been a long-standing question. The points made about wind and fuel consumption are things I hadn't fully considered before. I appreciate having them pointed out. The effect of waves is something I'm still a little unclear about, but I'll save the question rather than annoying anyone further.
J
Joe
Scot... it's not an annoying question....
To me it shows you're thinking. Why don't you come sailing with me in the ocean.... I live in Riverside also, but I keep my boat in San Diego. jofo@prodigy.net I've sailed on Lake Perris in my catamaran many, many times. On that small lake, you only have to contend with the wind (and the PWC yo-yo's). Wind waves are small though, and there is no current that I am aware of. It's like a nice flat, paved highway. Once a boat is up to speed it's momentum allows it to move smartly through the water thus requiring less power. The ocean, or any larger body of water, is a much more volatile place. When waves, wind and current oppose each other the water surface is no longer a smooth highway, it can be a very bumpy, undulating road. The boat's movement can become erratic, it's momentum being challenged as it tries to maintain speed through the water. Rather than moving straight through the water, the outside forces cause the boat to yaw, rise and fall, roll from side to side. These movements challenge the helmsman to stay on course, his rudder adjustments having an effect on hull speed also. Consider riding a bicycle on a smooth, flat, paved surface with no headwind and maintaining a maximum speed of 20 mph. Then take that same bike on an undulating, uneven road with a pot-holed, cracked surface and trying to maintain that same maximium speed. Here is where you would cry out for stronger legs, or a different gear ratio, to provide more acceleration power. Smooth road vs. bumpy road. That's it. Sorry for the non-scientific analogy. Hope it makes some sense.
To me it shows you're thinking. Why don't you come sailing with me in the ocean.... I live in Riverside also, but I keep my boat in San Diego. jofo@prodigy.net I've sailed on Lake Perris in my catamaran many, many times. On that small lake, you only have to contend with the wind (and the PWC yo-yo's). Wind waves are small though, and there is no current that I am aware of. It's like a nice flat, paved highway. Once a boat is up to speed it's momentum allows it to move smartly through the water thus requiring less power. The ocean, or any larger body of water, is a much more volatile place. When waves, wind and current oppose each other the water surface is no longer a smooth highway, it can be a very bumpy, undulating road. The boat's movement can become erratic, it's momentum being challenged as it tries to maintain speed through the water. Rather than moving straight through the water, the outside forces cause the boat to yaw, rise and fall, roll from side to side. These movements challenge the helmsman to stay on course, his rudder adjustments having an effect on hull speed also. Consider riding a bicycle on a smooth, flat, paved surface with no headwind and maintaining a maximum speed of 20 mph. Then take that same bike on an undulating, uneven road with a pot-holed, cracked surface and trying to maintain that same maximium speed. Here is where you would cry out for stronger legs, or a different gear ratio, to provide more acceleration power. Smooth road vs. bumpy road. That's it. Sorry for the non-scientific analogy. Hope it makes some sense.
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Dan
Scot, I'm saying...
current, waves, and even a headwind will make it more difficult to make headway if your prefered course takes you against these forces, especially all three at once. As far as I can tell, engine size will relate to fuel consumption and wear-and-tear only, given the engine gets the boat to hull speed.
current, waves, and even a headwind will make it more difficult to make headway if your prefered course takes you against these forces, especially all three at once. As far as I can tell, engine size will relate to fuel consumption and wear-and-tear only, given the engine gets the boat to hull speed.
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Scot
Thanks
Joe and Dan, thanks for taking the time. I appreciate your feedback, and I think I understand the subject better now.
Joe and Dan, thanks for taking the time. I appreciate your feedback, and I think I understand the subject better now.
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Eric
Sooner? maybe, but not later ...
Hello JR I have a 4hp 4 stroke because of weight. However if I were in your position I'd go with the 2 cylinder 8hp in a heart beat. You'll hold hull speed much easier. The quieter smoother 8 is a much more pleasant engine. With the added bonus of having more reserve power to tackle wind and waves. For best speed, keep her clean, light and if possible keel up. Weight and drag are your biggest enemies. Plus you'll be ready if you ever want to hit the coast. I am moving up to a 9.9 ASAP, but I will be keeping the 4 for when I want to go light. Fairwinds Eric
Hello JR I have a 4hp 4 stroke because of weight. However if I were in your position I'd go with the 2 cylinder 8hp in a heart beat. You'll hold hull speed much easier. The quieter smoother 8 is a much more pleasant engine. With the added bonus of having more reserve power to tackle wind and waves. For best speed, keep her clean, light and if possible keel up. Weight and drag are your biggest enemies. Plus you'll be ready if you ever want to hit the coast. I am moving up to a 9.9 ASAP, but I will be keeping the 4 for when I want to go light. Fairwinds Eric
A
Aldo
Eric..
Eric: I think that 9.9 may be a little extreme. I have seen a 9.9 (Yamaha) on a Catalina 22, but I thought that it looked heavy. I even think that 8 may be too much, but I think that the improvement in fuel economy may offset the added weight. I think that 6 gallons of gas weighs about 36 lbs, so if you can double your fuel economy, you could save the weight of the additional fuel. Next week, I'll be starting off with 2 full 6 gallon tanks, or 72 lbs of fuel. The other thing I wanted to mention is that I never felt that raising the keel would give you more than .1 or .2 knots increase in speed. We checked this with our GPS. Also, another C-22 was running behind us, and they pulled up their keel when we slowly sailed passed them, and we still kept pulling away from them. I don't think that the decrease in stability is worth the very slight increase in speed, under most circumstances. Aldo
Eric: I think that 9.9 may be a little extreme. I have seen a 9.9 (Yamaha) on a Catalina 22, but I thought that it looked heavy. I even think that 8 may be too much, but I think that the improvement in fuel economy may offset the added weight. I think that 6 gallons of gas weighs about 36 lbs, so if you can double your fuel economy, you could save the weight of the additional fuel. Next week, I'll be starting off with 2 full 6 gallon tanks, or 72 lbs of fuel. The other thing I wanted to mention is that I never felt that raising the keel would give you more than .1 or .2 knots increase in speed. We checked this with our GPS. Also, another C-22 was running behind us, and they pulled up their keel when we slowly sailed passed them, and we still kept pulling away from them. I don't think that the decrease in stability is worth the very slight increase in speed, under most circumstances. Aldo
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