Crusers guide to boat speed?

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Crusers guide to boat speed?

Post by JonnyBoats »

I know there are lots of handicapping systems for boat speed used by racers, but has anyone done a comparison of boat speed for cruisers?

By this I mean a table which would average day's run on a passage for various boats.
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Post by Rachel »

I don't know if this is the kind of information you're looking for, but I cruised long distance on both a Baba 30 and a Westsail 32. Over thousands of miles - counting both motoring and sailing - anchor up to anchor down, we averaged about 4.5 knots on both boats.

This was not the sort of cruising where you sit with sheets in hand, tweaking, although of course we did try for efficiency, and the boat must be balanced to use the windvane.

I bet my Westsail cruising bud did a speed average for just the time under sail; I'll see if I can dig that up and post back.

Edited to say: Without writing a bunch of things down and doing exact calculations, I did look at just the sailing stats (removing motoring) and I'd say the average speed for that was about.... 4.5 knots :D

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Post by Hirilondë »

A big consideration for average cruising speed is how important it is to cover miles and how much you are willing to use your engine. And even still the point of sail and weather for any given day will have a drastic influence on that day's progress. Rachel's estimates seem quite fair for an over all average speed.

It would be realistic to say even a boat in the high 20 foot range could do 4.5 almost all the time if the engine were used when needed. It would do even better reaching in a good wind, or reaching under power in light to moderate winds. It may do slightly better under power alone in light to no wind. Where you might be unable to make that rate would be to weather in a goodly breeze. Your boat speed might reach or even exceed the 4.5, but speed towards your destination will be less. Tacking lengthens your route a lot, and motoring into a sea is often far less than hull speed, depending of course on your engine.

When I cruise I plan each day differently. I figure I can do 50 miles during daylight under most conditions if I am willing to use my engine and use all of the daylight possible. This however may not prove a pleasant day and I will not attempt it unless the conditions are perfect or enjoying the day is less important than reaching my goal. The goal thing for me is almost never. I find 30 miles to be a pleasant day under almost any condition.

There is also the subject of tides and currents. These can change any estimate of boat speed under any other circumstance. Against the current in the Cape Cod Canal means making no speed what so ever over the ground. Going with the current means you can fly. Some days the currents favor you during the daylight hours, and other times they don't. Some days you have to leave really early to compensate, other days you might as well sleep in and wait for the change.

Even if you find a good average daily distance for cruising, it may be any where from easy to impossible to achieve on any given day.
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Post by Rachel »

Yep, it's so variable, isn't it? I can't think of ever seeing a table, like a PHRF table.

I think Jonnyboats is looking for average speeds on passage, right? Not day cruising? The overall average I gave took in thousands of miles - and included some day-long runs - but I think our passage average was about the same as our overall average. We didn't tend to just go out daysailing, as we had our dinghy for short distances, and if were weren't traveling, we tended to do other things such as snorkeling or walking on shore for food/supplies or for exploring.

In looking at three distinct long passage legs (over a week), we (sails only) averaged about about 3.5 knots, about 4.5 knots, and about 6.7 knots (gotta love the gulf stream).

We didn't carry a whole lot of fuel (40 gallons), so we either didn't motor (when others might have), or we motored at about 4.5 knots to conserve fuel (being sure to run at a higher engine load a certain percentage of the time for the health of the engine).

Some folks might fire up the engine when their sailing speed drops below 6 knots, and motor at 6 knots.

On the other end of the spectrum, a ketch I occasionally help deliver is 64' long and has twin engines. The owner (who is not along) asks that we add engine power whenever our sailing speed drops below about 7 knots, and we carried enough fuel to motor all the way from NYC to the BVI at over 8 knots - 550 gallons all in the tanks! I'm not sure what our average speed was on that boat on passage, but I would guess it at more like 7-8 knots.

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Post by Chris Campbell »

Regarding your boat specifically, John (the LeComte Northeast 38), I heard from someone who cruised in the tradewinds that they saw 150 mile days, which is great. I always counted on 120 mile days and motored when I dropped below 4 knots. Usually my estimates were conservative, so I was averaging a little better than 5 knots.

Hope that helps.

Cheers,

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Post by JonnyBoats »

OK, I guess I really didn't ask my question very well.

As a rough guide, one can use waterline length to determine how fast a displacement boat will sail when there is sufficient wind. The longer the WL, the faster the boat. In "nerdery terms" its the Renolds number (approx 1.3) x the square root of the waterline length. This is also known as "hull speed".

Of course we all know that many of our classic plastic boats have a longer waterline length when heeled than when sitting at the dock so they sail faster than what would be expected by their static waterline length. So has anyone put together a table showing the observed hull speed for various boats?

Next we have the question of light air performance, some boats move quite well in 8 knots of true wind while others are such underpowered tubs that they barely move.

Finally some boats simply point better than other boats which is an advantage in certain conditions.

Now considering two specific boats: An Island Packet 38 has a WL of 33 feet while a Hinckley Daysailor 42 has a WL of 29 feet. Somehow I don't think a IP 38 will be faster than a DS 42!

Which brings me back to the question: For someone who wants to go cruising, is there a simple guide somewhere which will help him/her decide if boat A or boat B would be faster "in general"?
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Post by Rachel »

I don't know of anything beyond the calculations you already mentioned. And just getting a feel for how different hull shapes perform in different conditions of wind and sea.

But finding the right cruising boat is about so much more than "speed," of a given boat, that I can't imagine it being more than a small percentage of the information one would use anyway (?)

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Post by JonnyBoats »

But finding the right cruising boat is about so much more than "speed," of a given boat
That is quite true. What got me thinking about speed is a friend who commented that if a boat "can't sail" nothing else matters (to a cruiser). I think he has a valid point.

One sees modern heavy displacement boats with lots of interior volume that have features like furling mains with negative or no roach, large dinghy davits and solar panels on the stern and large dodgers and Bimini's. They are often touted as ideal cruising boats by their vendors, but it would seem that their owners often use them more like power boats.
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Post by Hirilondë »

JonnyBoats wrote: One sees modern heavy displacement boats with lots of interior volume that have features like furling mains with negative or no roach, large dinghy davits and solar panels on the stern and large dodgers and Bimini's.
Don't forget my favorite: completely enclosed cockpits for indoor sailing.
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Post by Tim »

Trying to quantify sailing or relative comfort or individual taste or other performance by boiling these incredibly dynamic and ultimately subjective qualities down to numbers or a matrix strikes me as a rather silly exercise. It's impossible; why try?

As someone mentioned in another thread, there's room out there for everybody (except maybe blatant incompetents), and all boats. We don't have to like them all.

Life is all about choices; if everyone were the same, it'd be a boring existence. Sometimes people choose ugly or slow boats; we assume they have their reasons for such choices, as we all do with our own choices.

Good enough.
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Post by Chris Campbell »

As far as a guide to speed goes, there are a few: other owner's experience; phrf ratings; and gut feeling derived from your own experience with different boat types, among them. When I was shopping recently I used PHRF as a guide. I figured that while it wasn't the be-all-end-all, it at least gave me a way to compare boats using the same scale. That said, trying to accurately rank a variety of different boats for all wind and sea conditions is a fool's game - planing hulls, fixed propellers, overhangs, etc. all play havoc with relative speed, potentially making a boat with a higher PHRF faster than one with a lower PHRF in given conditions.

Knowing myself that speed and comfort in unsettled seas is important, since we have lots of that around NS, a narrow, reasonably deep and reasonably heavy boat for her length with enough ballast and sail area to drive her was important to me. A boat might not rate well under PHRF but might seem likely to be able to carry sail in sloppy conditions, which would offset the poor rating.

I was speaking with a fellow who had crossed the Atlantic with Non-ARC (an alternative to the current race-orientation and expense of ARC, still providing a group to cross the ocean with) with is wife in his C&C 38, in company with (among other boats) a Pacific Seacraft Orion 27 being singlehanded. The C&C 38 has a PHRF of around 110, the Orion about 273. The C&C around the bouys would whoop the Orion, but across the Atlantic, despite being singlehanded, the Orion was the faster boat. That's because she was much more seakindly, and could carry her sails in rising winds much better than the C&C.

I guess my point is that coming up with a way of rating boats against one another really depends on too many factors to be done well. That said, combining a variety of methods might come up with what you're looking for, more or less.

Now I'd better stop before I get a citation for rambling outside of the Rambling forum!

Cheers,

Chris
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Post by JonnyBoats »

Life is all about choices; if everyone were the same, it'd be a boring existence. Sometimes people choose ugly or slow boats; we assume they have their reasons for such choices, as we all do with our own choices.
I agree with you Tim _if_ people make informed choices. The problem comes when an uninformed person is sold a bill of goods by a slick broker or salesperson. I understand "buyer beware" but what I was looking for is something for the prospective buyer who _wants_ to learn before making a purchase.

For example if a newbie asked me "what gear should I have on my sailboat to be safe at sea" I would probably tell them to take a look at 2008-2009 ISAF Special Regulations Governing Offshore and Oceanic Equipment
and Preparation, including US SAILING Prescriptions. http://www.ussailing.org/safety/isaf_new.asp If they read it and then said "I' going to sail from Maine to Australia by myself in a 20 foot boat and I don't need no stinking life raft, radio or EPIRB" well...

On the other hand if I met someone getting ready for a voyage who didn't have those things and I asked them if they had an EPIRB and they replied "What's an EPIRB?" then I would take a different approach.

With respect to cruising boats, there is a lot written to help one decide the relative seaworthiness and safety of boats, for example http://www.sailingusa.info/design_winds.htm There is also a lot about speed for sailboat racers, but I just haven't run across much which would help someone rate boats on speed for cruising.
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Post by Quetzalsailor »

John, I thought you were trying to compare cruising boats to cruising boats under cruising conditions. I've seen nothing that would help you.

Comparing cruising boats to others under racing conditions is pretty readily done by reference to the various PHRF sites. In that, you'll find that your Mk II NE 38 lists in the 160s (w/o looking it up), an Island Packet 38 at 168; no doubt the Hinckley Daysailor is pretty slippery.

I think loading any cruise-worthy boat down with a couple thousand pounds of stuff will knock its PHRF expectations galleywest. Further, loading a cruiser-racer down with the same stuff will have even a greater negative impact. Two extra tons in your NE 38 would hurt your performance worse than the same 2 tons would in the Island Packet.

On the other hand, think how much your 'comfort ratio' would go up!

Another concern that I'd fret over is the expectation that cruiser-racers like ours are designed with weight and strength in mind to take the loads imparted by wind, wave and hull mass. Adding 2k lbs to our 16k boats runs the loads up on every part of hull and rig.
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Post by Zach »

My favorite way to think about boat speed, is in sail area to weight. (Goes back to my hotrodding days... Horsepower to weight!)

Your top speed is fixed, or to say it differently... your maximum speed through water is known. The more sail area you can carry for a given weight the less wind speed it takes to reach that speed.

The rougher it gets, the more weight you need to carry the sail. (Until you go so light that you end up with an Ultra Light Displacement Boat! Like Merlin.)

Its all good bench racing, I'm flirting with the idea that a Triton can shed some pounds... though only so she'll have less load to carry when loaded with gear to go cruising! At some point there is a point of diminishing returns and its all a waste of time... (Grin!)
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Re: Crusers guide to boat speed?

Post by dee »

I found this interesting for "simple" comparisons.

http://www.image-ination.com/sailcalc.html

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Re: Crusers guide to boat speed?

Post by Oscar »

If you want more speed and need to lengthen the waterline, just put a lot of stuff on the boat.
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Post by catamount »

JonnyBoats wrote:Which brings me back to the question: For someone who wants to go cruising, is there a simple guide somewhere which will help him/her decide if boat A or boat B would be faster "in general"?
Yes, the PHRF handicap tables will do that for you, assuming both boat models are listed (some strictly cruising models that have never been raced won't be listed). It doesn't matter that you are not racing, the handicaps will still give you a sense of the relative speed between the two boats "in general."

Besides that, the main factors to look at would be waterline (theoretical hull speed), sail area (ratio to displacement, SA/D), and displacement (ratio to waterline, D/L). Boat with longer water line, more sail area and less displacement will generally be faster.

Also, FWIW, I think the point that people always seem to raise about the "added" weight of a cruising payload and its relative impact on the performance of a racing versus cruising design is a bit misleading. Offshore racing boats are designed to be sailed with large crews (weight), who will have to carry plenty of provisions and gear (weight), a lot of required safety equipment (weight), and usually have a large inventory of sails (weight). Take the same boat cruising with just a couple: fewer people = less weight for the people and their gear. Maybe you have more provisions (per person) for the two people, but it may still be less weight than the fewer provisions for 8 people. Fewer sails = less weight. Sure you're going to add more conveniences for cruising (=weight), but in balance I don't think the difference in payloads between cruising and offshore racing is really as big as people make it out to be. (That said, a lot of cruisers could probably benefit by putting their boats on a diet and exercise plan!)
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Post by Bluenose »

catamount wrote:
JonnyBoats wrote:Which brings me back to the question: For someone who wants to go cruising, is there a simple guide somewhere which will help him/her decide if boat A or boat B would be faster "in general"?
Yes, the PHRF handicap tables will do that for you, assuming both boat models are listed (some strictly cruising models that have never been raced won't be listed). It doesn't matter that you are not racing, the handicaps will still give you a sense of the relative speed between the two boats "in general."

Besides that, the main factors to look at would be waterline (theoretical hull speed), sail area (ratio to displacement, SA/D), and displacement (ratio to waterline, D/L). Boat with longer water line, more sail area and less displacement will generally be faster.

Also, FWIW, I think the point that people always seem to raise about the "added" weight of a cruising payload and its relative impact on the performance of a racing versus cruising design is a bit misleading. Offshore racing boats are designed to be sailed with large crews (weight), who will have to carry plenty of provisions and gear (weight), a lot of required safety equipment (weight), and usually have a large inventory of sails (weight). Take the same boat cruising with just a couple: fewer people = less weight for the people and their gear. Maybe you have more provisions (per person) for the two people, but it may still be less weight than the fewer provisions for 8 people. Fewer sails = less weight. Sure you're going to add more conveniences for cruising (=weight), but in balance I don't think the difference in payloads between cruising and offshore racing is really as big as people make it out to be. (That said, a lot of cruisers could probably benefit by putting their boats on a diet and exercise plan!)
Tim,

Thanks for posting this, you just about nailed my thoughts on this topic.

With respect to cruisers boats speed. Back when I was on the fence between a smallish cruising boat and my current choice I would read everything I could about people's experiences with their boats. One comment that I heard often, that immediately caused me to scratch a choice of my list, was the ability to carry full sails in a 20 plus kts breeze. Now none of these boats had excessive ballast ratios so to me that meant they had way too little sail area to reach their hull speed in the light wind conditions that I like to sail.

So my cruising guide to boat speed would be find a boat whose owner's complain about having to reef frequently and early.
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Re: Crusers guide to boat speed?

Post by Chris Campbell »

I was chatting with a fellow who sailed across the Atlantic with a bunch of other boats (loosely organized as the non-ARC, in protest of what ARC has become (expensive and a race)). He and his wife were sailing their C&C 38, one of the other fellows was singlehanding his Pacific Seacraft Orion. The C&C 38's PHRF is about 102, the Orion's is about 243. the C&C's waterline is 30' 8" and the Orion's is 22'2". The C&C's hull speed is 7.42, the Orion's 6.31. But the C&C's motion comfort ratio is 22.12 and the Orion's is 33.42. The Orion, despite being singlehanded, was across ahead of the C&C. The reason was that the boat could keep it's sail up when the going got uncomfortable. It rode the seas well, with a slow, controlled motion. The C&C was like a cork - keeping the couple who were sailing it feeling like they were at the edge of control, and requiring them to reduce sail when the weather was less than perfect. The guy in the Orion simply left his spinnaker up and sailed away from them!

I'm sure that a team of racers on the C&C would've been across long before the Orion was - but they wouldn't have had a very good time of it! I guess the point is that there is more involved in daily mileage counts than just the ability of the boat to move through flat water.

My two (additional) cents.

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Re: Crusers guide to boat speed?

Post by bcooke »

whose owner's complain about having to reef frequently and early.
That would definitely be a Triton then. :-)
(though I would disqualify the Triton for long term/ ocean cruising on other grounds)
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Re: Crusers guide to boat speed?

Post by Oscar »

Yes, the PHRF handicap tables will do that for you, assuming both boat models are listed
One thing to keep in mind about PHRF. It is a LOCAL rating. The same model boat can have a different PHRF in Maine, on the Great Lakes or wherever. So, when comparing boats based on PHRF, make sure they are on the same list.
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Re: Crusers guide to boat speed?

Post by Bluenose »

Oscar wrote:
Yes, the PHRF handicap tables will do that for you, assuming both boat models are listed
One thing to keep in mind about PHRF. It is a LOCAL rating. The same model boat can have a different PHRF in Maine, on the Great Lakes or wherever. So, when comparing boats based on PHRF, make sure they are on the same list.
I like to use the Long Island Sound ratings since that seems more representative for light air comparisons. Especially compared to say, San Francisco.
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