Hull Speeds?

[Skipper Dave]

Just curious since we are all about the same size would stand to reason we should be of similar hull speeds, I'm gonna guess around 6.5.  How close am I?

[Frank]

Check out my 'ratios' post some where here and ya can figure out every boat if ya have the specs...plus there are a ton registered there now with specs ready  Just went and got it for ya...have fun http://www.image-ination.com/sailcalc.html   when the page comes up...scroll down until you see where to enter your info..enter it..hit 'compute'..scroll down a bit more for results..it is 'instant' once you hit compute....or...play with the comparisons already there

[Skipper Dave]

Thanks Frank I'm gonna check it out.

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This morning it looked so nice out I thought I'd leave it out.

S/V "Tina Marie" Cal 2-27

[FLIGHT]

Okay, I need some information, if you absolutely happen to know the scientific truth.

I know all about hull speed, and the hull speed for a Flicka is 5.7113078 knots to be precise.

BUT IN OVER A HALF CENTURY, I'VE NEVER BEEN ABLE TO FIND ANYONE WHO COULD REALLY TELL ME WHAT HAPPENS WHEN YOU FORCE A BOAT TO EXCEED HER HULL SPEED.

And here's my reason for asking:  when Heather transits the Panama Canal, she is going to be tied to the side of a tug boat.  But I KNOW that tug is not going to want to poke along at 5.7 knots.  I KNOW he's going to go on up to 10 knots or whatever.

So what is this going to do to Heather's boat?

I KNOW she'll have to double up on her port bow spring, breast line, etc., or it'll just break the lines.

But what else?

Is there any chance this speed could damage her FLIGHT OF YEARS?

Do any of you guys REALLY, REALLY KNOW FOR CERTAIN?

Thank you very much.

Reef early!
Gene

[Auspicious]

Hello Gene! Time is short here isn't it? What a wonderful holiday your family must be having.

I am a degreed naval architect and marine engineer (Webb Institute 1982).

Hull speed is in fact not a hard number. Hull speed is an attempt to describe the shape of a curve of hull resistance against speed. For most boats that is reasonably linear to some point (in knots, 1.1 to 1.4 times the square root of waterline length, depending on hull form -- 1.2 is often thrown around as "the number."). In fact the curve is a slope up to some point where it curves up to a significantly steeper slope.

When a hull is driven to speeds above the point where the resistance becomes nonlinear its response is depend on the shape. This is where planing hulls come up on plane for example. For displacement hulls, the response varies: it could simply plow (pushing lots of water in front of the boat) or it could submarine (self-explanatory, but not comfortable).

To my knowledge there is no algorithm you can plug numbers into and determine the response. That is why model basin testing is still done as part of ship design. If you really want to know in advance I would suggest pulling Flight of Years behind a tow-boat at increasing speeds.

I haven't looked at the lines for a Flicka, but based on photographs I expect that at some point a Flicka would begin to wallow and then submarine (the stern would lift from flow over the hull aft, burying the bow).

From what I have read of Panama Canal transits I think Heather might be best off paying the fee for a two-day transit. A side-tie to a tug in the locks would be great, but Heather will be much happier making the transit between locks under her own power. In fact, I am not aware of anyone who has done the transit in a side-tie, only during locking.

Let me know if I can do anything to help, and please let me know if you have different information about tranisting the canal. I think there is a transit in my future and I welcome any information.

[Frank]

I had the misfortune of being towed at 10knots on Jubilee...all the while yelling "SLOW DOWN'  to the tow captain by cell phone. The bow buries slightly at times and jubilee created quite a swell off her stern.It only lasted about 2 minutes...then the bow chock snapped.I was not happy.She seemed fine and well behaved around 7knots. Don't know what to tell ya...10 is no fun :(

[Auspicious]

It looks like Frank's data supports my assessment. If you go too fast in a Flicka she will eventually submarine. Not so good, not so fun.

[FLIGHT]

Thank you so very much for your INFORMED replies, AUSPICIOUS and FRANK.

Heather was aware of the potential problems which she may encounter in her transit, so she has already retained a prominent agent down there, who seems very eager to help.  And I will contact him further in this regard.

But first, I do not completely understand, Auspicious, what you mean by, "From what I have read of Panama Canal transits I think Heather might be best off paying the fee for a two-day transit. A side-tie to a tug in the locks would be great, but Heather will be much happier making the transit between locks under her own power. In fact, I am not aware of anyone who has done the transit in a side-tie, only during locking."

For openers, I'm not familiar with "paying a fee for a two-day transit".  I know about fines you have to pay if you're too slow, but is that what you're talking about?  They don't sound the same.

And what do you mean by "A side-tie to a tug in the locks would be great, but Heather will be much happier making the transit between locks under her own power."  Normally, when a yacht ties to a tug for the transit, does the tug pull him all the way through the entire canal?  I don't believe that would work, 'cause there's no way you'd be able to talk a Panamanian tug captain to stay at 5.7 knots or less for the entire distance.

But can you arrange to only be tied to the tug from one lock to the next?

But isn't even that distance too long for safety?  I.e., might he not still cause damage to Heather's boat by going too fast even just between locks?

These folks are not sensitive people determined to make your life more happy and comfortable for you!

IF THIS HULL SPEED IS GOING TO BE A PROBLEM - AND OBVIOUSLY IT WILL BE IF THE TUG PULLS HER MORE THAN 5.7 KNOTS FOR ANY LENGTH OF TIME - I'D MUCH RATHER SHE PAY OVERTIME FINES OR YOUR TWO DAY TRANSIT FEE, AND SIMPLY GO THROUGH THE CANAL ALONE LIKE MOST OF THE OTHER YACHTS.

I hate canals with locks.  They've always caused me problems, and I KNOW the Panama Canal will be utterly awful.  AND dangerous.  PLUS can you imagine Heather and four Panamanian line handlers and a Panamanian pilot, stomping their muddy feet all over Heather's polished FLIGHT OF YEARS - ALL THE WAY THROUGH THE CANAL??  Ugh!!!

Auspicious, please tell me exactly what you'd recommend, and then I'll contact Heather's agent and see if he can work it out for her.

Thank you very much!

Gene

[Godot]

I understand the minimum speed through the canal is supposed to be 8 knots or they assess an $840 penalty.  Sucks, but fair enough.  I have been reading the log of Carina (posted earlier by Skylark: http://www.meder.hu/ ... sadly the period where he actually transited was not documented), which is only 19' long and obviously doesn't come close to the 8 knot minimum.  Áron paid his fee, paid his deposit, and paid his penalty ($600+$850+$840) expecting to only get his deposit back.  Happy days, they also returned his penalty. 

Makes it sound like there is one rule they publicize, but another rule they follow. 

I thought it was interesting.

Good news: got word that the Canal Transit only cost $600, the extra $840 was credited back to the account. In reality the officials told me about two cases: if there was no towing, then they won't use extra $840 and it gets refunded. Another person said though that they'll not refund it...

[Auspicious]

Hi Gene!

Following up on the Panama Canal issues, and recognizing that while I have been reading about this stuff for many years, I have not done it myself. You may find, if you have Google Earth, that looking at the satellite imagery may help with the sense of scale tremendously.

But first, I do not completely understand, Auspicious, what you mean by, "From what I have read of Panama Canal transits I think Heather might be best off paying the fee for a two-day transit. A side-tie to a tug in the locks would be great, but Heather will be much happier making the transit between locks under her own power. In fact, I am not aware of anyone who has done the transit in a side-tie, only during locking."

There is a set of locks at the Gulf side and another set at the Pacific side. For small boats, the best deal you can get is to side tie to a larger vessel in the locks and let them deal with all the line handling. Heather would still be required to have four 100 foot mooring lines and the requisite fenders because "those are the rules."

As I understand it, she will follow the tug or other larger boat into the lock and tie up alongside. When the lock is flooded (or drained) she will untie and lead the other boat out of the lock. The larger boat will pass her before the next stage and she will tie back up to that boat (or another if so directed). To my knowledge boats/ships do not move from lock to lock tied together. Regardless, the distance between stages on the two sides of the canal are relatively close together.

The post above describing the requirement to have a minimum speed of 8 knots to make the passage between the East and West sides of the canal is correct. The "too slow" fine is what I was referring to when I spoke of paying the fee for a two day transit. I believe it would be money well spent in terms of both comfort and safety.

Auspicious, please tell me exactly what you'd recommend, and then I'll contact Heather's agent and see if he can work it out for her.

If you are clear about the capabilities of Flight of Years your agent should be talking to you about the realities of a transit.

I do have a number of friends who have made the transit. If you care to PM me the name of your agent I will poke around quietly and see what cruisers have to say about him.

Regardless, my recommendation (since you asked) is to have your agent arrange for the required mooring lines and at least three tires set up as fenders (with bags and lines). He should also be upfront with the canal authority about the speed of the Flicka and make sure everyone knows it will take two days to get through the canal. Heather should also be set to provide line handlers (you can generally get some from amongst the cruising community) and food and drink for line handlers and the canal "advisor" who will be aboard.

[AdriftAtSea]

Most boats don't do well when pushed to speeds above hull speed.  As pointed out previously, they will wallow and are in serious danger of being badly damaged. 

Not only are you required to have four 100' dock lines and fenders, but also are required to have four line handlers and a guide aboard.  Heather will be responsible for feeding the five people, and she'd best have a decent menu for them, since if the food isn't acceptable, they'll often order food at a fairly high cost to be brought to the boat.

[FLIGHT]

That's great, Auspicious, if I understand you correctly.

If all she has to do is tie up to the tug while the chamber fills or empties - THEN UNTIE and go on under her own power to the next lock?  THAT WOULD BE GREAT!

No hull speed problem.

BUT ALSO, since she would be tied to the tug, I would assume she would have need no line handlers, lines and such (other than her own lines and finders or the rental tire fenders), because there are no lines to the tug?  Or would she have to use lines from one lock to the next?

Heather was just here, a moment ago, and we discussed this at some length, but obviously she'll have to spend some time with her agent when she gets to the Canal.

I don't remember his name, but he is the one Jimmy Cornell recommended to us by email.

Thank you very much!
Gene

[AdriftAtSea]

Her agent should definitely be able to tell her whether she'll need line handlers and lines/fenders. :)

[Auspicious]

BUT ALSO, since she would be tied to the tug, I would assume she would have need no line handlers, lines and such (other than her own lines and finders or the rental tire fenders), because there are no lines to the tug?  Or would she have to use lines from one lock to the next?

As I understand it, *everyone* needs line-handlers, lines, and fenders in case plans change.

Heather should be prepared to provision for and feed herself, four line-handlers, and the canal advisor. There should be plenty of time for shopping and advance food preparation after she arrives and checks in while she waits for her appointment to transit. As I understand it the advisor will almost certainly go home over night during the two day transit, but she will need to provide for the line handlers. I expect if she hires line handlers they will go home, but she will be expected to pay transportation. Cruisers are more likely to stay aboard. I think the cruiser option is better, mostly because you don't have to worry about someone showing up on time the second day. It's always good to have people you are counting on where you can see them!

Whether Flight of Years is normally "dry" or not, Heather should have some beer aboard for the end of each of the two days of transit for the handlers and the advisor.

If I recall correctly, Heather is not carrying an SSB radio. I suggest she watch for other boats heading for the canal who do and stay in touch through them with the cruiser's nets on HF -- she can probably line up friendly line handlers that way and be all set when she reaches the canal.

I'm excited about her departure just having read all the pages on the web site -- you all must be spinning!

sail fast, dave

[FLIGHT]

Great, Dave, I apprecite this.

No, though Heather drinks beer, she will not normally have any aboard, and she will not be drinking while at sea, but she would stock up for her help as you suggest.

Yes, she has a SSB receiver, but no transceiver.

We're still fighting the weather here.  A relatively violent cold front is due to come in the day after her departure date - January first - and it's really messing us up just now.

Interestingly, she went out sailing yesterday, so she could warm up her engine, on the way back in, and check the drip rate from her stuffing box, and she several times, under sail, got the boat up to its hull speed of 5.7 knots.

Thank you very much again!
Gene

[Auspicious]

I'm pleased to be of some small help.

I participate in a lot of fora at various levels of enthusiasm, so I have watched with some interest the different level of discourse on the subject of your daughter's adventure. It is an interesting practical exercise in sociology, although perhaps a bit too personal for you. <grin>

Something somewhere (I think a discussion on water capacity) leads me to suggest -- baby wipes. One of the refillable plastic containers and half-a-dozen or so refills can make it much easier to feel clean which helps with morale as well as conserving water.

Similarly, if somewhat inelegant, several containers of Tucks also help with feeling clean and again improve morale.

As long as I'm offering unsolicited advise, Heather should plan to touch (not just look - touch) all fruits and vegetables at least every other day. Whatever is soft can be pulled into the galley and worked into the meal plan. I'm not a huge fan of the Pardeys (I differ with them on outfit and heavy weather issues), but I do commend Lyn's book "On the Care and Feeding of Sailing Crew." It is a useful and entertaining reference. Heather would be well-served to take a copy along. It doesn't weigh much, and if she doesn't like it as much as I do she can trade it for something else down-island.

We all make our own choices. I outfit my boat with SSB rather than sat phone. Perhaps I am influenced by my long ham radio licensure (although I am more a builder than a talker). I do think there is much to be said for the community that builds in the various nets. At this point choices have been made and Monday morning quarterbacking is not useful. Tactically, I think Heather should work to develop a VHF connection as much as she can as larger, faster boats pass her and keep in touch with the SSB nets through other boats. The VHF connection can serve as a back-up to the sat phone. Does Flight of Years have a fixed VHF? Does Heather have a handheld or two? I would hope so.

I envy Heather her set date to launch her adventure. I think often of sailing to the mouth of the Chesapeake and turning right. Perhaps if I leave soon enough I can catch up!

sail fast, dave

[FLIGHT]

Thanks for the note, Dave -

Boy have you got me pegged - I'm decidedly not a forum person.

This particular forum, SailFar, is the only forum on which I've lasted more than two or three days.  But I've never encountered as many kind and courteous gentlemen as I have met here.

My age and background pretty much prevent my relating to the average forum person, or rather perhaps his relating to me.  But I surely have enjoyed every post I've read here!

Heather has a SSB receiver, in the form of her Grundig World Band portable, and having used SSB transceivers for over thirty years, I've personally found most of the chit chat is mostly yachtie wives swapping receipts and gossip, endeavors into which Heather is not involved.  If there is something important to be heard, like weather information, she will hear it, but she won't need to swap gossip at the same time.  AND, if she has a real emergency, the sat phone will reach help far more rapidly that a skipping SSB.

Yes, Heather has a masthead 6db VHF and the top-of-the line handheld unit, one or the other of which will always be turned on 24/7.  She also has the USCG Disaster Relief phone numbers, which she can reach in mere seconds on her Iridium sat phone, and they have assured her that if she is in an area which they cannot service, they will instantly relay her distress message to the appropriate authority, and follow through on it.

Yes, of course, go on out the Chesapeake, turn right, and you'll catch her slow boat in no time.

Thanks,
Gene

[CharlieJ]

This particular forum, SailFar, is the only forum on which I've lasted more than two or three days.  But I've never encountered as many kind and courteous gentlemen as I have met here.

My age and background pretty much prevent my relating to the average forum person, or rather perhaps his relating to me. 

rofl Gene- some of us are in the same age range you are- I'll be 67 next month and my wife is the same age Heather is, or really close.

We don't REALLY know how old CapnK is though ;D ;D ;D

But there ARE a lot of really nice people on here- we've had a jerk now and again, but they seem to fade away soon.

[Captain Smollett]

We don't REALLY know how old CapnK is though ;D ;D ;D

He is, to within a few months I think, the same age as me.  That helps, right?   ;D

[FLIGHT]

Charlie . . . .

Dear boy. . . .

I'm TEN YEARS older than you are!

I'll be 77 February 25th.

Gene