Discussion of HP required to move sailboats....

Started by Lynx, March 09, 2008, 07:55:46 AM

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Lynx

I have run into people who know what they are talking about but want to tell you wrong and other who know what is right but will not tell you just to see you do it wrong.

Do you know how many boats cannot motor into a 15 moh wind with 2 - 3 foot seas.

Just yesterday I saw a boat dock 3 hrs before a front was due and their bow line was too short to be thrown to the dock. Their dog was on deck, in the way.

I have seen way to small of anchors and motors on boats as well. It as if the boat repair people want money from you and the insurance Co.

I have been told to move from my mooring because the boat at anchor next to me would swing into me.
MacGregor 26M

AdriftAtSea

Lynx-

If you're on a mooring, doesn't it mean that you, or at least the mooring ball, was there prior to the knuckleheads anchoring...and according to common sense and anchoring etiquette, the newcomer idiots should be moving, not you.  UGH... there are some truly ferociously stupid people out there.
s/v Pretty Gee
Telstar 28 Trimaran
Yet we get to know her, love her and be loved by her.... get to know about My Life With Gee at
http://blog.dankim.com/life-with-gee
The Scoot—click to find out more

Bill NH

#2
Quote from: Lynx on March 09, 2008, 07:55:46 AM

Do you know how many boats cannot motor into a 15 moh wind with 2 - 3 foot seas.

I'd disagree with this one belonging on your list if we're talking SAILBOATS.  This certainly includes every boat cruising and making passages engineless out there, and I'd wager that most of the people doing so are BETTER sailors than even your average cruising sailor, never mind the marina moguls...

Perhaps it should be people who cannot sail "into a 15 moh wind with 2 - 3 foot seas" without firing up the engine...
125' schooner "Spirit of Massachusetts" and others...

Lynx

#3
Bill - I know that this is a bit off for some but I have been into far to many situtations where I needed to move the boat into winds above 15 and seas of 3 feet including into Harbors and docks (not much waves at the docks. Without the ability to move the boat in tight quarters I would have gotton into trouble quite easily. OR had to delay long passages.

I think that it is grand that people do not want to motor and have small outboards but the cost and weight differance of a 6 hp vrs 10  hp and a 10 hp vrs 15 hp is not that much compaired to the damage that can happen.

Sometimes I have made bad judgements that require the bigger hp to get out of it and have same me money, time and greif.

Jim Baldwin and others more exeperience sailors than me have told me that the more experience you are the less hp motor you need and I agree.
MacGregor 26M

CharlieJ

#4
Quote from: Lynx on March 09, 2008, 07:55:46 AM

Do you know how many boats cannot motor into a 15 moh wind with 2 - 3 foot seas.



Just a week ago last Thurs, Laura and I motored Tehani dead upwind into 25 MPH winds, gusting 30, through a narrow place where we were unable to tack- about a 3 mile motor. Wasn't fun to say the least, but that 8 HP Yamaha running at the start setting ( JUST above 1/3 throttle)   pushed us just fine. Seas were very short and choppy because the water was only 7 feet deep, so it was NOT a comfortable ride.

When we got past the shoals we were skirting, we turned up the channel, on a broad reach, set the jib and cranked the boat up for some miles  of 7.5, 7.8 sailing ;D With one surge of 8.1!!

THAT was a blast ;D

We ran from about 12 miles out, to the marina and tied in the slip, in 1 hour and 14 minutes-WOOHOO!!!

Edited to add-

AFTER we got in, the real winds cranked up, which was why we came in- the forecast was for winds in the 40s and they didn't miss it by much.
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

Lynx

On bigger motors, in order to get there in the bigger seas and winds like these -






HE has a 25 hp on a MacGregor 25S. In about 3 hrs it got windier, about 12 miles from Bimini. If we had to turn around it would have been 50 miles to Miami.
MacGregor 26M

CharlieJ

curious about something- why didn't he have any sail up at all? Why run only under power?

Not trying to be picky here, just wish to know the reasons.
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

Lynx

No problem. We had a wind shift about 1/2 way and had to go straight into the wind. Earlier he had up a reefed main. The coastal weather forcast turned out to be different that forcasted. If we had put up a little sail it would have taken an extra 2 or 3 hrs and we would have arrived at dusk.

We left at 5am and should have left at midnight. A hard 10 hr trip for him as he did not have an auto pilot and his wife was not strong enough to stear in those conditions. Me, my aotopilot saved the day.
MacGregor 26M

Captain Smollett

Quote from: Lynx on March 09, 2008, 11:35:09 AM

the cost and weight differance of a 6 hp vrs 10  hp and a 10 hp vrs 15 hp is not that much compaired to the damage that can happen.


I think we've discussed this before.  For a 5000-10,000 lb boat like many of the full keeled sailboats represented on this site are, going from 6 to 10 or even 15 HP gains you virtually nothing. The HP to displacement numbers are in a completely different part of the performance spectrum you are experiencing with a big engine, light boat.  The Mac 25 you showed is operating with a HP/ton ratio of about 25.  My boat with a 15 HP OB (assuming I can get all 15 hp to the water) is  3.3 HP/ton.  HUGE difference, and I'd only gain an increase in weight on the stern and double fuel consumption for NO performance gain.

It's interesting also that some find sailing in 15 kts with 3-4 seas very enjoyable, even on a beat.  I guess it's just one of those things that goes under the 'to each his own' category that makes sailing, sailboats and sailors so diverse and interesting.

One other question, by the way.  Why would raising a sail while motoring have cost you 2-3 hours?  Wouldn't having some sail up steadied the boat some (I've never sailed on a Mac25, so I don't know how they handle under sail or power), even while motorsailing?
S/V Gaelic Sea
Alberg 30
North Carolina

Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.  -Mark Twain

AdriftAtSea

I've got a 20 HP on my boat, and they offer a 50 hp, but I couldn't see any real benefit to having that much horsepower, at the cost of having an extra 110 lbs. hanging off the aft end of the boat.  Some of the people with the 50 HP report they can only make 10 knots, while I get 7.5 WOT on my boat, and probably a lot better fuel economy.

I'm also curious as to why you wouldn't at least put up a double reefed main on that MacGregor.  I've not sailed on them much, but would think that having the steadying effect of the sail would help the boat.   

As for the conditions CS describes, 15 knots of wind 3-4' seas... that's a lot of fun in my book, and quite enjoyable, since I could probably go 10 knots under sail, far faster than I could under power.
s/v Pretty Gee
Telstar 28 Trimaran
Yet we get to know her, love her and be loved by her.... get to know about My Life With Gee at
http://blog.dankim.com/life-with-gee
The Scoot—click to find out more

Lynx

We were dead into the wind on a 60 mile crossing. In these conditions we would loose 30 to 40 degrees to destination. If we had left at midnight it would have been easier although taking a few hours longer.

Being able to push through waves and wind is an advantage if you put yourself into conditions that need it. If he did not have the 25 hp then we would have had to turn back as I would not wait outside Bimini at night. The winds would have been bad for waiting.

This is my buddy boat in the Bimin crossing in Nov '07.

I to enjoy sailing in 15 knots and 3 foot seas IF I am going in the direction needed getting there on time. The Gulf Stream eats boats of all sizes and I take no chances.

The fuel economy is good with the new EFI engins. In these conditions I was getting 7 mpg at 7 mph but most of the time I get from 10 to 13 mpg below 7 mph.
MacGregor 26M

s/v Faith

I split this topic off since it really had nothing to do with the other thread.

  FWIW, I do believe that John is correct.

QuoteI think we've discussed this before.  For a 5000-10,000 lb boat like many of the full keeled sailboats represented on this site are, going from 6 to 10 or even 15 HP gains you virtually nothing.

  The HP to displacement numbers are in a completely different part of the performance spectrum you are experiencing with a big engine, light boat.  The Mac 25 you showed is operating with a HP/ton ratio of about 25.  My boat with a 15 HP OB (assuming I can get all 15 hp to the water) is  3.3 HP/ton.  HUGE difference, and I'd only gain an increase in weight on the stern and double fuel consumption for NO performance gain.

  I can tell you that having run a 6hp, 8hp, and 9.9hp on my boat there is NO gain in using the 9.9, it only increases stern squat and causes a variety of handling problems related to pushing the hull into the bow wave.

  I suspect that was also part of the issue with the boat in the pictures (nice pictures by the way).

 
Satisfaction is wanting what you already have.

Lynx

He claims to have gotton 2 extra mph with the bigger motor and I know that I can move the boat much easier at the dock from forward to reverse and a quick turn. I also know that inorder to maintain speed I have to imcreasse rpm's in harsh conditions like these. This cannot be done with a smaller outboard.

So the question could be, in what conditions to you need more hp to be safe or not damge your boat?

Most of the sailboaters that I talk to cannot motor into a 20 knot wind even if their life depended on it.
MacGregor 26M

Captain Smollett

Quote from: Lynx on March 09, 2008, 10:21:21 PM

He claims to have gotton 2 extra mph with the bigger motor and I know that I can move the boat much easier at the dock from forward to reverse and a quick turn. I also know that inorder to maintain speed I have to imcreasse rpm's in harsh conditions like these. This cannot be done with a smaller outboard.


But again you are talking about boats that are 1 tonners or thereabout.  If I double the hp on my boat, top speed will not change.  Period.  The HP per ton change is neglible.

Quote

So the question could be, in what conditions to you need more hp to be safe or not damge your boat?


Again, I cannot add enough HP to my boat for it to be a "safe" motorboat in the terms you are thinking.

I consider 0 HP to be safe.  If I don't count on having an engine and keep my boat 'safe,' then having the engine can only help.  It really boils down to a matter of psychology.  I view my boats as sailboats.  I've had engines fail on me too many times in 'critical' conditions - bad fuel, wrapped props, whatever cause - to count on an engine for anything.

I'm talking about the mindset that it's a sailboat FIRST.  Period.  Everything about her design centers on the sails and the rig.  If I cannot sail into/out of a situation, probably best to avoid it.  15 kts on the nose and 3 ft seas is not conditions I would avoid sailing in.

Quote

Most of the sailboaters that I talk to cannot motor into a 20 knot wind even if their life depended on it.


Why would I try to motor into 20 knot winds?  Why?

I lot of folks suffer damage to their boats motoring into conditions that are really not all that unsafe.  The number one rule is do what the boat needs...she'll "tell' you what she needs.

I've sailed into 20+ kt winds.  So again, why would I try to motor...in other words, why would I rely on my engine in conditions that are easily sailable?  "If their life depended on it" to me implies that I got myself into a situation believing I was going to rely on the engine to get me out, but at the risk of being redundant, I'm talking about a mental approach that precludes that belief.  I NEVER approach seamanship as "sails okay, engine if need be."

Neither of my boats are motor boats...they both handle rather piggish under power.  Both sail rather well, even in conditions far more trying than you describe.  On my small boat (1350 lb dry displacement), I rather enjoy sailing in 20-25 kts.
S/V Gaelic Sea
Alberg 30
North Carolina

Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.  -Mark Twain

Lynx

Your point is well taken. I wish that I could say the same about my boat but I did not buy it to be a pure sail boat. I motor most of the time so it makes me more a motor sailor than a sail boat. Watching the bigger boats leaving and getting into a dock makes me wonder if they would be better off with more motor.

If one knows what their boat can do under many different conditions, that would be prudent. However, the basis of the starting thread was not this but my point was under HP motors on sailboats. Having more power has gotton me out of a great many situations. I have seen a few boats where more hp in reverse or turning would have prevented problems. The same goes for going under bridges and getting out of somebodies way. Like a 3 burner stove having the extra burner is nice but not needed most of the time.

If you are happy with your boats HP and performance then do not change it.
The best is to know what your boat can do under all conditions and make it work for you.

Greg - on the squatting. I don't know. It may be a trim problem or a loading problem. He is in the Exuma's, Long Island.
MacGregor 26M

Captain Smollett

Quote from: Lynx on March 09, 2008, 11:12:02 PM

Watching the bigger boats leaving and getting into a dock makes me wonder if they would be better off with more motor.

my point was under HP motors on sailboats.

Having more power has gotton me out of a great many situations.

I have seen a few boats where more hp in reverse or turning would have prevented problems.

If you are happy with your boats HP and performance then do not change it.


The point is that on most of our boats, more HP will make no difference.  That's that point I am trying to get across.  I could quadruple the HP of the ob on my A-30, and the handling under power would not change.  There's simply too much boat, and the wrong underwater hull shape.

A Mac 25 or MAc 26 is a completely different animal.  No one is arguing that for YOUR boat, a big engine gives you no benefit.  But you are saying that for all these other boats, they are underpowered.  That's not quite true.  The are generally if anything overpowered already for what such an engine can possibly give them.  They are not motor boats and will not handle like motorboats.  Period.


Quote

Greg - on the squatting. I don't know. It may be a trim problem or a loading problem. He is in the Exuma's, Long Island.


Craig mentioned stern squatting with larger hp ob's on his Ariel - that's not a trim issue.  That's because the boat reached "hull speed" and the bow is rising on the bow wave - it cannot climb out like a planing hull.  All that can happen is the stern pushes down.  So, any extra horsepower simply pushes the stern down - it does not make the hull move faster through the water or handle any better.
S/V Gaelic Sea
Alberg 30
North Carolina

Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.  -Mark Twain

CharlieJ

Quote from: Captain Smollett on March 09, 2008, 11:21:41 PM



Craig mentioned stern squatting with larger hp ob's on his Ariel - that's not a trim issue.  That's because the boat reached "hull speed" and the bow is rising on the bow wave - it cannot climb out like a planing hull.  All that can happen is the stern pushes down.  So, any extra horsepower simply pushes the stern down - it does not make the hull move faster through the water or handle any better.

Exactly! On Tehani we can achieve hull speed running just under the "start" position on the throttle (8hp 4 stroke Yamaha). Increasing to the half throttle position gets us MAYBE .5 knots faster ( that's 1/2 knot), then the stern begins to squat. Running at WOT we get ZERO increase in speed, and lots of water in the cockpit because the cockpit drains go under as the stern squats even more.

Tis the shape of the hull- it's a displacement boat, will NEVER move much faster than hull speed, other than surging down a wave front ( which is how we saw 8.1 on the GPS sailing a week ago or so). It WILL sail faster than that though- again because of hull shape- as she heels, the longer overhangs immerse and the waterline lengthens- giving a higher theoretical hull speed. Still looking at about 6, 6.2 tops though.

I'm a dealer for Mac 26 M's by the way. Got a brand new one sitting out front right now. The boat is a compromise. Pretty fair sailboat ( better than the X in my opinion) and a good power boat- but it's hull is more optimized for power- it's a PLANING hull and can use the extra HP to get up and over the bow wave. Displacement boats like John's and Frank's and KaptK's ( and Tehani ) cannot.

And as I said in an earlier post- recently Laura and I motored dead into 25 knot winds, gusting higher. We were also powering against a light tide. We did it because we had been anchored in a bay off the main bay, heard a forecast of STRONG winds with rain coming that afternoon, that night and the next day and decided to head for the marina. We had to traverse a 3 mile area with a sand bank on one side and oyster shoals on the other- no room to tack safely. So our choices were to stay anchored out for two days, or try to beat the stuff back to the marina. We chose to try to beat it. And we did- but it wasn't comfortable- it was wet going and we weren't making real good time - maybe 3, 3.5 knots. But at no time did we need more than half throttle to power the boat and keep it under control.
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

Lynx

Interesting points and well taken.

Lets take a Flicka. Per what I have been told that it cannot motor into a wind of 15+ with the stock motor. Would this have been solved with a bigger motor?

I have heard that some sailboats have trouble stopping at the dock. Would this be solved by a bigger motor?


(moving today and will not have net for about a week)
MacGregor 26M

Frank

#18
 I was very dissapointed with the flicka's performance motoring into the wind. Having previously owned a yanmar powered boat with similar displacement...I feel it was a prop issue.The previous boat had a 3 blade...the flicka a 2 blade. At no time did rpm's go down while motoring into a sea, but the speed sure did.I have recomended Jubilee's new owner get a 3 blade. On my 'new' jubilee I installed a 6hp with an extra long shaft and power prop. I love the fuel consumption,light wieght and low cost overall.I find this motor exellent for my cruising style.I have previously cruised the Bahamas on a heavier boat with a 6hp as well. Yes...at times going into the wind I wish I had more power...I think we all do "except if ya have 50HP out back  ;)"  but I would not change my purchase in any way. I feel 'safety' on a small OB powered boat comes from 1-a proper prop 2-extra long shaft to keep prop in the water in a seaway 3-a remote shift/throttle. This allows much beter control while docking as you are not reaching back over your transom to shift into reverse etc.
God made small boats for younger boys and older men

CharlieJ

as for stopping at a dock-

I've always operated on this theory- which an old man told me when I was in my Sea Explorer days. He said"Son, always operate your boat as though you didn't HAVE a reverse. Then when you really need it, it MAY do the job"

If I'm approaching a dock, I do so at a speed where the reverse is a convenience, NOT a necessity. Coming into our slip, we lose almost all way BEFORE we get there, then bump it in with forward if needed. We lay along side docks the same way, stopping short then making the final speed adjustments with forward.

Now reverse is one failing of our boat, I will admit. With the outboard we don't have much reverse particularly backing to starboard- the boat almost will not back down that way- she will back to port once you learn how- power up, get her moving THEN idle the engine and then put your rudder over. Since the engine sits in a well, there is really no turning it, so you learn how to back up without turning the engine.

In two trips to Florida via ICW, some 3400 ICW miles, we've done quite nicely.

You should also keep another old sailing trick in mind- spring lines- properly used, a spring line can flip you out of a slip or off a dock as neatly as can be. ;D
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera