|Topic Review (Newest First)|
|03-23-2007 12:53 PM|
"what's the point of that crappy emergency tiller handle "
You can bring it home and use it to beat to death the alleged engineer who designed the rudder component that failed? (That was the builder doesn't have to pay unemployment for firing him.)
|03-23-2007 11:38 AM|
Originally Posted by T34C
i will give Hunters their due, they are very swank. at my previous slip i was next to a Hunter 30, and i drooled over all the shiny bits. looking at my 40 year old Islander 29 in comparison made me feel very light in the jockstrap. however, with my 1960's over built hull, and in general built like a tank structure, in any but ideal circumstances i would feel a heck of a lot safer in mine...
|03-17-2007 05:23 PM|
Originally Posted by camaraderie
Your comment set me thinking about the rudder on my CS 36T, which I think serves as a good example of how design details set the good apart from the not so good. The 36T has a spade hung off a skeg and the rudder is about 2.5' shallower than the keel. The hidden detail is that the SS rudder post and flange within the rudder ends half way down the rudder - the lower part of the rudder is a sacrificial shell designed to fail if the rudder is subject to extraordinary forces. There are a number of stories in owner lore from the 20-25 year life of these boats, of owners reaching port with half a rudder, but not any I've heard of total rudder loss.
Sometimes what you can't see in a boat is as important as what you can. It wouldn't cost that much more to design a rudder to avoid total failure, but you can't add quality details, especailly hidden ones, like that to boats built to a bottom-of-the-market price point.
|03-17-2007 04:39 PM|
It is possible the CG instructed the crew to secure the tow hawser to the windlass. This could, and would, be done with larger vessels. The towed vessel, assuming the hawser is clapped on to the anchor chain, would then fleet out sufficient chain to make abrasion of the hawser a non-factor. The anchor windlass is also likely to be the most secure fixture on the bow. We now get around to the point raised by Valiente and Blue, most yachts have cute, shiny, and weak fixtures in their bows. A cruciform bitt, as pictured, provides the width of base to be securely backed below and distributes the load over a wider area of deck. The greater the area of contact with the deck, and by extension the backing plate, the greater the strength imparted.
The next factor to be considered is the tow hawser. When being taken under tow by a large hawser it is essential that a large amount of catenary be allowed to develop. This means a long hawser. Two to three hundred feet would not seem out of line, and perhaps substantially more. What cannot be allowed to happen is 'straight lining' of the hawser. A relatively small yacht, being towed by a large diameter hawser, will never stretch the hawser prior to structural failure on the yacht. The stretch we take for granted in our anchor rode will not be present in the size hawser likely to be passed. The anchor line, doubled up and passed through the eye of the hawser, can provide a measure of stretch not provided by the hawser and it is probably the strongest part available on the yacht.
The towing vessel should gain way slowly while taking up the tow. The weight of the catenary will bring the towed vessel into motion. Foolishness arrives when the desire to yank the towed, possibly off a lee shore, overcomes the benefits of a gentle strain. The old adage regarding lines, any lines, is "strain it-don't part it". Whether the line parts, or the attachment point, the towed vessel is adrift and probably worse off.
A possible compromise, necessitated by inferior hardware forward, would be to secure the hawser to the available fixtures forward (more than one cleat) with mooring lines. A rolling hitch with the mooring line around the hawser and thence to the cleat, using as many cleats and lines as available, would work. The procedure for doing this involves bringing approximately a length of hawser equivalent to the length of the vessel on board, claaping on the mooring lines with rolling hitches, and then fleeting out the hawser to one half the length of the vessel, and making the mooring lines fast to their cleats, taking an even strain on all parts. Then the hawser could be led aft and, assuming a keel stepped mast, secured about the base of the mast. Smaller lines can be rigged at the bow to fairlead the hawser dead ahead over the bows.
This is also the time at which it will be found desirable to have an axe, or more practically a hatchet. If it becomes necessary to sever the tow immediately, your basic knife (I don't care the blade is hand forged of unobtainium!) will prove deficient. A good sharp hatchet will allow you to use much more force in severing the line(s). The resultant damage to your deck probably not being a major concern in this eventuality.
The CG does not do as much towing as one might think; certainly nothing like the experience of your tow boat operator. Good communication, if possible, can preclude worsening the situation.
I would also caution of drawing too much from the media in dissecting these types of incidents. The "allision" I was involved in, anchored in the roads off Little Creek, VA, was reported in the local paper. There was little follow up, as my vessel fortunately did not blow up (1,500 tons of ammo in No.1 hold made this a concern) and what was printed in the paper seemed to come from the designated CG pr personnel. Suffice it to say, they got the name of the vessel and the anchorage correct. After that, one began to wonder which ship they were discussing as it did not sound like the incident of the night before.
|03-17-2007 03:19 PM|
I am suprised that the delivery captain did not require the boat to be equipped with an emergency rudder system for the trip to Hawaii. A independent steering system is the only truly redundant setup IMHO. I'm pretty sure this is a requirement to enter either the TransPac or Pacific Cup.
I think it's amusing that the rudder is a weak link in a +200k boat; what's the point of that crappy emergency tiller handle they provide when you have no rudder? (Only supplied to make the buyer much more confident in the seaworthyness at the showroom)
|03-17-2007 12:58 PM|
Originally Posted by camaraderie
It's really a matter of how you want to sail. The list of "fast" fin keeled, spade-ruddered boats that are also good for extreme or even stormy conditions is pretty short, in my view, and as the Americas Cup designs hint at, we may be approaching the limits of our materials science in getting ULDBs that can take the kind of hits the sea can dish out.
Would I like a J/160 or a Saga 48 or a Swan or even a more conservative Moody? Yes, I would...because such boats are on that list. Nothing by Hunter, Catalina, Beneteau, Jeanneau, Dufour or Bavaria is on that list. Tartan is a maybe.
Of course, I'm the annoying bastard who shows up at boat shows with a dental mirror and a flashlight to view the backing plates under the (too short) stanchions, or who counts the hand holds in the (too wide) saloon. The Lloyd's Ocean certification is handed out far too liberally, in my view. But I am very much in the minority these days, and frankly, if one in 100 production boats actually goes offshore, I would be surprised.
|03-17-2007 12:11 PM|
Redundancy is always nice when help is 1000 miles away... I agree that the keel and skeg mounted rudders are better supported both at the top and bottom.
I have a kickup spade rudder on my boat, but it is really a requirement of the desing, being a multihull, with a draft of 14" with the board up.
BTW, the rudder on my boat works, although not as well, in the up position.
|03-17-2007 11:37 AM|
|PBzeer||I remember reading in one of the sail mags that they had a couple of boats lose rudders (neither of them Hunters) in one of the recent East Coast to Caribbean races.|
|03-17-2007 11:33 AM|
|T34C||Anyone want to weigh in on weather the Hunter should have been out in the middle of the Pacific in the first place??|
|03-17-2007 11:29 AM|
SD...I know you know this..but a lot of comments about skeg rudders focus on the protection from debris and other objects afforded the rudder by the skeg. Just as important to me is the support for the bottom end of the LEVER that a spade rudder becomes and the spreading of those forces to the entire hull through the skeg rather than focusing them on the rudder stock alone.
As you point out...the rudder also doesn't go to king neptune if one of the two supports should fail. Of course a spade post can be over-built to minimize the risk of failure...but i prefer redundancy especially for offshore cruising...even at the cost of some speed.
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