Re-design your boat drains and thru hull fittings.

[john_morris_uk]

I can understand your worries if you have had problems with a boat taking in water, and I seem to remember your thread on the subject. It sounded as if the boatyard didn't take as much care as they might have or it was an extremely unlucky co-incidence.

However I do nearly all the maintenance on our boat. When we bought the boat, many of the skin fittings and sea-cocks were suspect and mentioned as such in the survey. I replaced them all personally and I KNOW that they are bedded properly, made of good quality materials and don't leak. I have no reason to think that things will change, and (as I said before) I check them and make sure that they are not seized or gently corroding away. We have FOURTEEN underwater holes in the boat - and I have no intention of altering things. It works fine as it is.

Get a surveyor to have a look if you are worried and then keep a seamanlike eye on your boat and fittings and you will be fine.

 

[jimbaerselman]

[ QUOTE ]
He said my deck and cockpit drains should be re-designed and simply let drain somewhere above the waterline, and not as they are presently lower down below the waterline, you can also use nylon and no need for bronze or whatever.

[/ QUOTE ] I would hope no-one 'qualified' recommended nylon on an above water skin fitting. Nylon is subject to UV deterioration, and after sufficient exposure, the lower part of the fitting is likely to crack. Then when the boat heels . . .

Bronze, fitted with compatible bronze bolts, or Marelon are suitable.

 

[richardandtracy]

Jon_Morris_UK, No, I'm not a troll. I do have my reasons.
I plan to take a yacht as far south as I can get it - basically until the sea goes hard. In these conditions I half expect to get iced in and need the boat to be as strong as possible while I attempt to get it out. Through hull fittings are vulnerable to that type of abuse. Others can do what they wish, and with my blessing.
Oh yes, I see little point in having un-necessary luxuries in the boat that I don't have at home. I have been accused of being an 'eco-freak' simply because we have a composting toilet to save the soil for growing vegetables.
Regards

Richard.

 

[Bajansailor]

Just my two cents worth re how we do drains....... my philosophy is to turn everything off (re skin fittings below the waterline) whenever there is nobody on the boat, especially when we leave her on the mooring.
We used to have 2 x 1.5" diameter cockpit drains exiting the hull via a couple of skin fittings directly under the cockpit, about 18" below the waterline. Had to leave them on all the time when the boat was on her mooring, unless we wanted a flooded cockpit. So a few years ago I took them out, glassed up the holes, and fitted 2 x 1.5" drains out the back of the cockpit, going to skin fittings under the counter P & S, about 12" above the waterline. New system works brilliantly - only disadvantage is that water comes in the leeward drain when heeled, and the helmsman gets damp feet if standing on the cockpit sole.

Here is a true story about failure of a skin fitting leading to a complete loss while on an Atlantic passage - and the vessel concerned was owned by Prof Arthur Beiser, who wrote the two volumes of 'The Proper Yacht'.
Have a look at http://www.bwsailing.com/01articles/issue/0802/special%20section.htm
and scroll down to 'A sinking out of nowhere'. I have read elsewhere that they had approximately 34 different skin fittings below the waterline on Isle, and they could not establish which one was leaking, resulting in the boat foundering.

I

 

[john_morris_uk]

[ QUOTE ]
Jon_Morris_UK, No, I'm not a troll. I do have my reasons.
I plan to take a yacht as far south as I can get it - basically until the sea goes hard. In these conditions I half expect to get iced in and need the boat to be as strong as possible while I attempt to get it out. Through hull fittings are vulnerable to that type of abuse. Others can do what they wish, and with my blessing.
Oh yes, I see little point in having un-necessary luxuries in the boat that I don't have at home. I have been accused of being an 'eco-freak' simply because we have a composting toilet to save the soil for growing vegetables.
Regards

Richard.

[/ QUOTE ]Well good luck to you. I have been in the Antarctic and the Arctic(albeit on a large and warm ship!) and I assume that if you are going that far South you have a steel vessel. I certainly wouldn't like to take our GRP boat however sturdily she is built into the ice. We were iced in a couple of times, and the noise and pressure of the ice is difficult to explain. It probably helped my peace of mind that I was on a Lloyds 100A1 Ice Breaker!

Not too sure if having no fittings below the water line will really help. You Porta Potti contents will have to go over the side eventually. I dodn't have a problem with it. The sea manages to eat up all our human body waste so long as its not too big a quantity at a go...

The very old ice (you can read up how to tell old from new) and I mean 'old' ice that is 1000 years old or more 'pings' when you put it in your gin etc The gas bubbles have been compressed over the years, and they 'ping as the ice melts in your drink.

 

[alec]

[ QUOTE ]
[ QUOTE ]
...The Health and Efficiency...

[/ QUOTE ]
Now that is a totally different organisation than the one you meant - Freudian slip? /forums/images/graemlins/grin.gif

[/ QUOTE ]

It's a fair cop..................

It must be the imminent school break-up's that reminded me of my own school days.

 

[l'escargot]

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
...The Health and Efficiency...

[/ QUOTE ]
Now that is a totally different organisation than the one you meant - Freudian slip? /forums/images/graemlins/grin.gif

[/ QUOTE ]
It's a fair cop..................

It must be the imminent school break-up's that reminded me of my own school days.

[/ QUOTE ]
Innocent days....

and why was there always someone leap-frogging? /forums/images/graemlins/grin.gif

 

[alec]

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
...The Health and Efficiency...

[/ QUOTE ]
Now that is a totally different organisation than the one you meant - Freudian slip? /forums/images/graemlins/grin.gif

[/ QUOTE ]
It's a fair cop..................

It must be the imminent school break-up's that reminded me of my own school days.

[/ QUOTE ]
Innocent days....

and why was there always someone leap-frogging? /forums/images/graemlins/grin.gif

[/ QUOTE ]

Yes they were always leap frogging ! Perhaps only naturists know why.

My copies were far more dog eared than this one. Hardly readable er I mean gawp-able.....

 

[richardandtracy]

John,


You lucky so & so. I have dreamed for may years of doing just that. One silly thing I want to do is to have some Arctic and Antarctic ice cooling the same drink.

My Spray was a steel Bruce Roberts Design. I've done some considerable stress analysis on it and finally came to the following conclusions:
1) The the through hull fittings could be sheared off by ice.
2) The vessel would still float in a severely distorted shape provided there were no fittings that leaked because circular holes turned oval. The hull could stand about 150 tons crushing it before deformation exceeded 300mm. If the load were applied within 300mm of the water line, the boat would pop upwards out of the water at 100 tons crushing load.
3) The stress concentrations, when the boat was being crushed, around the fitting holes were about 1.5x the basic stress, leading to them being the potential cause of a hull failure under extreme deformation. This stress occurred at approximately the same crushing load as would lead to the vessel squeezing up out of the ice (floe shape permitting). Removing hull fittings meant that there was a margin of about 50% between being squeezed up out of the ice and hull failure - definitely on the right side.
4) Under 2 or 3, I could probably say goodbye to the prop and its drive shaft, hence the well & layshaft.

Other analyses showed the boat could probably survive a 100ft wave, but only if I could submarine the boat into the front face of the wave before the top fell on me. Deformation of the cabin top in this case would be around 150mm and it would need luck for the hatches/ portlights to stay sufficiently watertight with such distorted frames (needless to say I built my own frames to reduce deformation and ensure a geometrical lock so they would follow the hull). To be honest, I'm not sure if I'd have the nerve to save my life in those circumstances. I'd probably freeze with fear for too long, but if I didn't..

The biggest problem though, for this boat, was a noisy neighbour. We had to sell the boat & house so that we could afford a quieter place where SWMBO could live without a nervous breakdown. C'est la vie.

Regards

Richard.

 

[Danny Jo]

[ QUOTE ]
Here is a true story about failure of a skin fitting leading to a complete loss while on an Atlantic passage - and the vessel concerned was owned by Prof Arthur Beiser, who wrote the two volumes of 'The Proper Yacht'.
Have a look at http://www.bwsailing.com/01articles/issue/0802/special%20section.htm
and scroll down to 'A sinking out of nowhere'. I have read elsewhere that they had approximately 34 different skin fittings below the waterline on Isle, and they could not establish which one was leaking, resulting in the boat foundering.

[/ QUOTE ] Fascinating link, thanks. I like especially the quote in the last paragraph where Callahan replies to the question, does he still sail?

“What else would I do? Where else can I find a place where knowing very little about a lot of things is so useful?"

The very essence of a YBW forumite?

 

[john_morris_uk]

Its taken me a while to get round to reading the article that you linked to. I am not sure that it alters my feeling about skin fittings at all. His boat was also a loss due to going to sea ill prepared and with poor vessel knowledge and poorly installed batteries and bilge pump arrangements. These were just as a big a factor in the loss as the skin fitting failure.

In fact if he had found which skin fitting or pipe had failed, and simply put a bung in the hole, the vessel would not have been a total loss at all, and would have experienced a minor incovenience during the transatlantic passage.