Minimum size for ride comfort?

[SamM1234]

I am in the process of negotiating with a boatyard to custom build a power boat for me. My main concern is the ride comfort for the passengers. Currently, I have a 35' sailboat, which I love to sail myself. The problem is any time I have guests, especially women, someone always gets seasick, which ruins the whole experience. Sometimes, I have people getting sick even in near calm conditions. In about 3 - 4 foot swell, one can't move around the boat without holding on to something. Can anyone advise what minimum size of the boat I have to go for to have sufficient comfort level for people, who are on the boat for the first time without taking any medicines? I read many posts on here that say that the size is a matter of preference. But, I think there should be some objective known number above which, one can say that the first time sailor will be comfortable on the boat. Maybe, someone has charter experience taking groups out on different boats??? I am considering a larger power monohull or a catamaran. It needs to provide comfortable ride in 3 - 4 foot swell at slow speeds and at anchor. It would be a shame to spend the money and have to sail by myself again! Your opinion is much appreciated.

[ted655]

:confused: So many questions!
Type of powerboat? Center console, open? Cuddy? Cabin cruiser, salon? See & be seen speed boat with bow & aft "waving hands" seating? Trawler?
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I would want to be on a boat where I could quickly move to a more secluded area, where I might do my retching in private. Also, be able to sit THERE, in comfort until my trips to the rail had run their course. I would not want to stink up the whole boat or ruin the outing for the rest, OR have everyone watching my misery up close & personal.
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Seating also depends on the length of time on the boat. We just completed a 1,000 trip where we were @ the helm for around 10-12 hrs a day. EVERY seat on the boat wore thin after 3 days out. The 4 of us ALL wished we had our home recliners to sit in. For extended rides, the seating must be the most comfortable that $$$ & space can allow.
.
I'll tell you this... typical factory boat seating SUCKS! You are right in thinking that seating is a very important part of enjoying a "pleasure" boat. Kudo's to you for thinking ahead!:)

[mmd]

There are many questions yet unanswered (How many passengers? How long a voyage? What speed do you want to cruise at, etc.), but given the small amount of info provided, if the boat is going to be forty feet or longer, I'd give serious consideration to a catamaran. I designed & built cats, both power & sail, for the charter trade in the Caribbean, and the ride ine even 6 - 8 ft seas was quite tolerable.

However, there is always somebody who get's seasich looking at a picture of waves, so it is impossible to please everybody. E-mail me at mmason2@eastlink.ca if you would like to discuss a design further.

[PAR]

Sea sickness can affect everyone differently, so a size would be difficult to pin down. My wooden, 63' ketch, which I chartered in the Caribbean for a number of years, didn't experience much difficulty in this regard, but there were occasions that someone would get ill.

Many things can affect the likelihood of this. Drinking, remaining below, not being able to focus of a specific task, some types of food, physical issues, genetic disposition and mind set can all cause someone who normally wouldn't get sick to become sick on an outing.

Some people are just more likely to get sick then others.

Things to look for in another yacht would be a D/L of 250 or higher. Also boats with not so high a ballast/displacement ratio, will help.

Many modern craft have a pretty quick roll moment, which doesn't help things. These boats are usually pretty fat butted too, which can increase the yaw tendency in some conditions. Look for a full bellied yacht like an older Island Packet or Cabo Rico.

In the end experience, personal preparation and life aboard will govern who will get some motion discomfort. The key is to nip it in the butt, before it's an issue, because once the cycle is started, it has to run it's course. Wrist bands, medication, a boat with a comfortable motion, keeping the guests busy, limiting drinking, not permitting someone with a hang over aboard, eating habits, etc. will help, but you'll always run the risk, because ther's only so much you can control.

[SamM1234]

Thank you for all the feedback! Good point about having a secluded place for retching, btw. To answer the questions, my design is not done yet, but I’m leaning towards a cruising power catamaran with two or more state rooms, main saloon, and open or enclosed fly bridge. Most of the trips will be only a couple of hours at 8 to 15 kts with up to 10 people, and a lot of time at anchor. I guess what I had in mind is the worst case scenario, when you have a girl, who is the first time on the boat, was drinking the night before, and didn’t take any motion sickness medicine (if you invite a couple, and the girl does not have a good time, the guy will not have a good time either). I know on cruise ships, not many complain about motion sickness. On my boat, almost everyone gets sick. So, is there some reasonable size in between that 99% of people would not even get a hint of seasickness, or is it just too large and prohibitive to build? I am also still not sure about going with a catamaran. Is the two-hull design more comfortable at all boat sizes, or is there some size, beyond which, a catamaran does not offer any comfort advantage? Most commercial passenger vessels or large yachts are not catamarans.

[Frosty]

[QUOTE=PAR;172210]
Many things can affect the likelihood of this. Drinking, remaining below, not being able to focus of a specific task, some types of food, physical issues, genetic disposition and mind set can all cause someone who normally wouldn't get sick to become sick on an outing.

Nothing to do with the boat going up and down then?

Sea sickness is simply a confliction of information from the eye and from the ear.

The eyes say things are not moving but the ear says differently.

Once up on deck the eyes and the ears agree that things are moving. Thats why its best to be up top looking forward , then when the boat moves the eyes see the reason for it and there is no confliction

From a womans point of view size does matter, and where boats are concerened --very much.

Catamarans give a very violent motion that can be as sicky as a mono hull,--. A semi displacement cat on the other hand is a very soft ride.

[rwatson]

Good luck - sea sickness will occur on any and all boats! The only really effective method is to leave the boat tied up at a sheltered dock - and even then some people will feel queasy!
Effective sea sickness pills were only resaerched during world war ii, when many sailors had it chronically. They were on veeery big boats - much bigger than most of us can afford.
The BIG factor, is if the visitors actually take something for sea-sickness in plenty of time. You almost need to watch them take it, especially kids, as many people are averse to pill taking.
Previous advice about diet, weather conditions etc, is extremely pertinent.
One hint I can give you, a sea sickness preventative that seems effective 95% of the time - keep the tips of your or guests fingers in a cold airstream. I was first told this as a kid on a bus trip. By sticking my fingers of one hand out the bus window as far as the first knuckle, my nausea went.
Years later on a boat, I tried this with other people. You cant really stick your fingers out a window, but tell them to hold onto a railing or edge that is on the windward side of the boat- seems to work a treat.

[Frosty]

Keeping the knuckles cool in a cool air stream only works if you stick your tounge right out and balance a spoon on your forehead, Works for me!!

[SamM1234]

Interesting. I thought planning hulls or semi displacement were less comfortable than full displacement. Can you explain about that?

I don't know if I should use something new like that, but what about wave piercing or foil assisted cats? Would any of that help to have a steadier ride or better speed and range? My objective is to have a vessel with long range and good economy at slow speeds, 8 kts or so. But, it will still be nice to have a high speed capability on short trips.

[rwatson]

Re wave piercing catamarans - I have travelled on them and displacement ferries. Was never as sick as on the cat.
So was everyone else, and they discontinued the cat service across Bass Strait after two seasons.
They certainly rolled a lot less, but the constant veering and dipping caused by the water jets doing the steering made even a calm crossing real upchuck material.
I have never travelled on a foiler, but seeing films of them travelling in really rough seas in the mediterranean was very impressive.

[FAST FRED]

"Most of the trips will be only a couple of hours at 8 to 15 kts with up to 10 people."

The USCG requires a far different vessel to risk over 6 folks at a time .
If these folks are going to PAY for the priveledge you will need a license and the vessel will need to be built to USCG specs.

Fire retardant resin (if GRP) collision bulkhead and proper bilge pumps as a start.
The CG will need to review the plans before any building is done , and will come by at times .
Google USCG Subchapter "T ", and be prepared to follow the requirements to the letter.

Have you looked at the USED market ?, you can usually save 50% to 80% if a production boat will fit your needs.

Look in "Boats & Harbors" for the boat of your dreams , and save 2-3 years of building, outfitting , testing.

FF

[ted655]

:confused: What's up with Cat lovers? Catamarans seem to hold a spell over some people that I, frankly don't understand. Just like 7 bar jazz, I guess it's a beat that is only soothing to some.
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For my money, they have more "issues" than rewards & jazz sounds like every instrument is on a different tune. NOT knocking either, but I just don't see the allure to either. I must have a simple ear & a too practical eye.
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Sea sickness has so many causes that combine, there probably no way to design a silver bullet for it. Some can't ride in the back seat of a car. Others are sick 1 day out & then get their sea legs. Others do OK as long as they see a horizon. Some are set off by diet or drink, & still others can't put their ear up to a sea shell @ home. I say don't design a boat to prevent sea sickness but design it to deal with it. Lots of rail space & wash down scuppers:D

[masalai]

Keep the boat & go cruising solo to meet a seaworthy crowd, or sell the big boat & get your fix on a "beach" catamaran as they are fun and easy to launch solo & keep at home.

[tom28571]

Having recently crossed the English Channel on the huge and high speed cat ,"vomit comet", I can report that neither size nor number of hulls guarantees a smooth ride.

[Fanie]

The most comfy ride is on the BIG boat called land.

You could of course have this boat with LCD screens on the windows which looks like you're on the sea - have nice calm weather all year round, the dolpins and whales will be there consistently every time, and somewhere in the trip you could even have some scene happen where your experience and bravery saves the day. Be a hero every day ;)

[masalai]

Long, Long ago, in the days before steam, a cruising sailor suggested

Your boat should be as small as will meet your needs, yet as big as your maintenance budget will allow.

[Fanie]

O-hor, you must choose the chicks better so they won't get sea-sick on the one you have :rolleyes:

Why hasn't someone come up with a sea simulator you can practice in so you won't get seasick after a while ?

Did you take your sea sickness pills ?
No, I was on the simulator this time... :D

[SamM1234]

Yes, I'd be interested in hearing more cons of catamarans as far as the ride is concerned. Efficiency wise, I know they are about the same as mono hulls at slow speeds. The builder is suggesting a cat saying it is better at anchor and more comfortable. But, I could obviously save some money if I go with a mono hull (or build a bigger one). I've also never been on a wave piercing cat. Does that really help anything or is just a fad?

No way, I'm not cruising solo any more. I need to get a girlfriend!

[masalai]

Sam, I was not suggesting to cruise solo, but in cruising, attract a sea-kindly partner.

Might I suggest several bare-boat charters of different cats to get the feel. That is the best way to sort out any differences in form & function.

I may be biased (I am but), from my observations, American designs seem to have a narrower beam overall (to fit in marina berths?) than cruising forms in Europe, South Africa and Australian regions.

Your ocean playground looks as though it will be the Pacific. Compare the seas in your area, I guess at a long swell as opposed to the short chop (comparatively) in the Caribbean? - showing my lack of local knowledge - having never sailed that side.

If that is the case, look at NZ and designs built/popular in Qld Gold Coast, NSW in Australia, or South Africa. Not to discount others, but to narrow the initial range/choices arbitrarily.

[longliner45]

the old addage comes to mind,,,you cant please all the people all the time ,,if they get sea sick ,,its not your fault,,,you can try to accomodate them all ,but that is futile, they must help themselfs,,if they cant do that ,,after you have gone through some lengths and exspence,,,,,,get new friends ,its cheaper and easier,,espesially if you have a boat,,,longliner

[masalai]

Yo longliner, Great minds think alike. My play area as power-linesman was 33k & 11K volts of private powerlines from Dampier thru Tom Price to Parabudoo iron ore mines. It powered after transformers, the switch gear & railway controls. Good fun when major work was at hand otherwise dead boooooring.

[ted655]

Seats should be...... 17" high, 34" wide & 14" deep. That was THE question, right?

[rwatson]

Ted655

You missed the real minimum dimension - lay back seats - people dont get sea sick when they are asleep, and closing ones eyes cures sea sickness.

Just dont pack the layback seats close together - the snoring keeps everyone awake!!

[Fanie]

I have a better idea. You dump the scuba gear when no one looks. Then get a piece of cedar (I've heard the Kiri may even be better :rolleyes:) and use it as the plank. Then get a friend who likes to go diving walk the plank and disappear after falling off, reason is he got sea sick last time, sorry standard practice of getting rid of sea sickness in these parts. No one will sleep and no one dares to get sea sick ;) No snoring either.

Eh, there's a shark ! Who's sea sick ? Come on people we need entertainment around here.

[SamM1234]

This will work, but you can't seal the deal if she's ill, if you know what I mean!

I think we need to come up with some objective standard for ride comfort measuring. In my previous life, I was a pilot. In aviation, they have a way to report in flight turbulence, which is different from how the sea states are recorded. Sea states are classified based on something that can easily be measured such as wave height. In the air, no one can see the air flows, so they apply the "coffee cup" scale. E.g. a mild turbulence is the one that creates some ripples on the coffee, but none is spilled, moderate is when some amount is spilled, and so forth. Severe is when the cup is thrown violently around the cockpit. Now, it is a well known fact that the turbulence experienced inside an aircraft is inversely proportional of its size (and the wing load ratio). What a Cessna reporting as heavy might feel only as mild in a 747.

Maybe, we can apply something similar to boats. I know in my boat in 3' swell, objects will shift and often fall of the shelves, if I do not secure them (I haven't attempted the coffee cup). Obviously, as the boat gets bigger relatively to the waves, there should be less motion inside. But the question remains, given the constant wave height (say up to 6'), is the motion inside a linear function of the size? Or, does it drop fairly quickly at small sizes and then the slope becomes shallower as it approaches 0 at big sizes? I think it has to be the latter, as the motion cannot be less than 0. Sorry if I sound technical, but what I mean is if the motion feels mild in a 100 footer, it will still be mild in a 200 footer, so there’s no need to spend the money on a 200 footer, if a 100 footer will do (for sickness purposes). So, I'm looking for that critical boat size, beyond which the "slope is shallow," and the motion is only felt as mild. Any thoughts, anyone?

[PAR]

MCR = Disp / (2/3*((7/10 * LWL)+(1/3 *LOA))*Beam4/3 )

Above is a commonly employed formula, which has marginal results. Below is taken from Ted Brewer's web site describing this "Motion Comfort Ratio" formula.

"This is a ratio that I dreamed up, tongue-in-cheek, as a measure of motion comfort but it has been widely accepted and, indeed, does provide a reasonable comparison between yachts of similar type. It is based on the fact that the faster the motion the more upsetting it is to the average person. Given a wave of X height, the speed of the upward motion depends on the displacement of the yacht and the amount of waterline area that is acted upon. Greater displacement, or lesser WL area, gives a slower motion and more comfort for any given sea state.

Beam does enter into it as wider beam increases stability, increases WL area, and generates a faster reaction. The formula takes into account the displacement, the WL area, and adds a beam factor. The intention is to provide a means to compare the motion comfort of vessels of similar type and size, not to compare that of a Lightning class sloop with that of a husky 50 foot ketch.

The CR is : Displacement in pounds/ (.65 x (.7 LWL + .3 LOA) x B1.333). Ratios will vary from 5.0 for a light daysailer to the high 60s for a super heavy vessel, such as a Colin Archer ketch. Moderate and successful ocean cruisers, such as the Valiant 40 and Whitby 42, will fall into the low-middle 30s range.

Do consider, though, that a sailing yacht heeled by a good breeze will have a much steadier motion than one bobbing up and down in light airs on left over swells from yesterday's blow; also that the typical summertime coastal cruiser will rarely encounter the wind and seas that an ocean going yacht will meet. Nor will one human stomach keep down what another stomach will handle with relish, or with mustard and pickles for that matter! It is all relative."

http://www.tedbrewer.com/yachtdesign.html

Like many of the formulas used in yacht design, it isn't perfect by any means, but can serve as a base for comparative study, across several yachts.

[SamM1234]

This does seem like a good estimate based on a boat reaction to a single wave. It should work well for comparing boats of similar size. But, I think as the boat size goes up relatively to the length of the waves, it no longer fits entirely in a trough and sits on multiple crests. So, multiple waves are acting on the hull at the same time; some are causing it to raise, some to descent. In this situation, many wave forces cancel each other out. If the boat size is really large relatively to the waves, they would not be felt at all. So, the larger length should actually increase comfort in this scenario.

[longliner45]

I also dont think it matters that of the size of the boat; people get sick on super yachts and dingys ,,I recomend ginger root ,,gingerale and dramamean patches ,,and a view of the horizon is good too,,some times people who are alreaddy a little bit sick on land ,,like a cold or light flu,,have the symptoms amplaphide on a boat because your body never really gets to relax.you are constantly holding or pushing or gripping,,even when you sleep ,I have always felt sorry for people who get sea sick,,longliner

[Frosty]

Admiral Lord Nelson was sea sick for the first 3 days of a voyage.

Every body can get sea sick or at least nausea. Fear of sea sickness can make you sick.

There is no reason to be sick ,--it is all in the head.

However it can cause loss of conciousness in a serious case.

Throwing a violently sick person over the side with a rope tied round them may seem cruel but it will revive them. It cuts out the third motion ---just you and the sea instead of you, the boat and the sea.

It also cleans them up a bit.

[Willallison]

Aha - at last! Frosty, you have made a sensible suggestion;)

The problem is - as others have already said - is that different things will make different people sick. Catamarans, as a result of their increased beam and subsequent initial stability, tend to have a short, fast, jerky motion. Vessels with less initial stability and a slower roll period have a correspondingly slower more gentle motion. Some will tend to be upset by the 1st set of circumstances, others the latter. Then there are those who get motion sickness on an escalator.

The wave-piercers tend to be very good in a surface chop. The sort of slop that would make many other vessels uncomfortable. But the instant they are exposed to larger waves (like swell), then they are definitely one of the quickest means of recycling carrots...

[Frosty]

Talking of mono hulls and cats --both motion can make you sick if its not what your used to. You can get land sickness if you have been at sea long enough.

Its simply a motion that you are not expecting.

I remember a friend who had a cat paid me a visit on my mono hull on anchor, after a while he excused himself to return to his cat as he was feeling nauseous. I visited him and experienced nausea too.


I know many people that aclimatize them selves to ocean motion by going on a mooring for a day or two. This is not a cure but it helps a lot, especially if you've got a newbie on board.

[FAST FRED]

D Gerr covers "Surge" , in his book. Graph included for ocean going boats.

FF

[ted655]

Maybe this thread is still alive. I just ran across this picture of some of the BEST seating I've seen OR set on myself.:)

[Fanie]

Couple a complaints already Ted. No drink holders, ash trays or rod holders. I suppose the personalized table is out of view, otherwise how is this going to be comfy ?

[ted655]

This isn't "rod holder" seating. The post was for comfortable guest seating while taking in the sights on a sunset tour.
Ah, but you're right, mo good deed goes unpunished1 Sorry I woke you.:(

[Fanie]

I'm not shooting your post down Ted, I was just looking at the pic and they do look really nice, you confirmed the comfort of them. Since one is going to pay top $ for them, I missed the functionality, but that's probably just me.

Given a choice of the ones like on your picture and the same ones where you can put a bit of loose things in, like keys, binoculars or other loose ends and yes a drink holder, I'll choose the latter. Te-he... someone may forget some small change in their's :rolleyes:

Personally I prefer seating with arm rests too, feel uncomfortable for me if my arms hang. One can also make a faster get-up out of a chair when THE FISH IS BITING :D

Really nice looking chairs. An don't be so sensitive, if it has tits, tires, or a transom, there's gonna be issues !

[ted655]

I am in the process of negotiating with a boatyard to custom build a power boat for me. My main concern is the ride comfort for the passengers. Currently, I have a 35' sailboat, which I love to sail myself. The problem is any time I have guests, especially women, someone always gets seasick, which ruins the whole experience. Sometimes, I have people getting sick even in near calm conditions. In about 3 - 4 foot swell, one can't move around the boat without holding on to something. Can anyone advise what minimum size of the boat I have to go for to have sufficient comfort level for people, who are on the boat for the first time without taking any medicines? I read many posts on here that say that the size is a matter of preference. But, I think there should be some objective known number above which, one can say that the first time sailor will be comfortable on the boat. Maybe, someone has charter experience taking groups out on different boats??? I am considering a larger power monohull or a catamaran. It needs to provide comfortable ride in 3 - 4 foot swell at slow speeds and at anchor. It would be a shame to spend the money and have to sail by myself again! Your opinion is much appreciated.
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Sorry, you're right, a bit sensitive. The guys boat is probably fitted out by now anyway.
I thought these seats were a good "visual". Not perfect, but intended more for inside seats I think. I can see 2 sets, facing each other, with a couple "plug in" tables, (WITH drink holder holes), and 6 people enjoying their cruise.
BUT... that's just me, I'm a hopeless &**%* romantic. My arse has sat on worse.:D

[Fanie]

I always say, the dog chasing the rabbit doesn't know it has fleas. It is the one lying about the yard that does the scratching...

My advice to SamM1234 would be to get his passengers to keep buzy and make it fun, there mustn't be time to become seasick. I almost doubt if the seats would make that much of a difference.

Have some ginger cookies for everyone, the green ones you force feed ;)

You can't and won't please everyone every time and all the time. Some people were sea sick already when they heard of the trip. My ex is like that.

Maybe if the seats really hurt, like the church ones they won't have time to get sea sick but complain about the seats instead :D

The best trick would be to keep everyone buzy and interested.

[ted655]

Allow me to translate that for landlubbers:)
"Sick, pucking & rushing to the rails"
:D :D :D :D :D

[messabout]

The other option for cruising as well as "closing the deal" is a motorhome RV . Some of those things are opulent beyond belief. The big ones wont rock or pitch even when there is some athletic pursuit inside. You won't even need PFDs. Cost about the same as an equivalent boat. The only drawback is that they do not sail very well.

[TeddyDiver]

Submarine, any size...

[eponodyne]

The other option for cruising as well as "closing the deal" is a motorhome RV . Some of those things are opulent beyond belief. The big ones wont rock or pitch even when there is some athletic pursuit inside. You won't even need PFDs. Cost about the same as an equivalent boat. The only drawback is that they do not sail very well.
I've often thought of buying an old Airstream and putting it on an oversized pontoon boat. That right there's high-style livin', y'all!

[ted655]

It ain't no Airstream, but.......:D

[SamM1234]

Actually, looks like someone took this idea very seriously. Take a look at this http://www.terrawind.com/terrawind.htm, an amphibious motor coach yacht. It's good to see that for every conceivable idea, there's an entrepreneur who's done it already. I bet I could find a submarine coach too if I looked on the net some more…