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S&S Swan General - Swan 41 Safety Audit
05 October 2015 - 00:33
Join Date: 01 January 2011
Posts: 36

Swan 41 Safety Audit
We're preparing Scotch Bonnet for a safety audit to allow racing this year. One requirement which is worrying me and I can't think of an easy fix is that under ISAF/YA Rules bilge pumps are not allowed to discharge into cockpit or cockpit drains. I've found only 1 website that qualifies the discharge into a cockpit drain by saying "unless water can run uninhibited to the sea", which in our case would be fine. May I ask the experience of others on this point, I'm assuming that Scotch Bonnet's pump outlets, which branch on to the cockpit drain pipes just above the skin fittings, are standard? If there is any danger in the existing arrangement I can't see it but it would be nice to have a documented answer in advance of meeting the safety auditor. Many thanks, Andrew Scotch Bonnet 41/039

05 October 2015 - 09:59
Join Date: 02 March 2007
Posts: 83

Dear Andrew,

I had the same problem when I was getting the UK SCVC (small commercial vessel certificate) for my 41. As the arrangement was in the original design, and the boat was built long before there were any regulations, I was allowed a concession on this and a few other points.

Cosmo Little

05 October 2015 - 20:07
Join Date: 02 January 2008
Posts: 1547

Dear Andrew
The requirement you mention origins from the Fastnet 79 investigations. It was concluded that bilge pump and other hoses connected to cockpit drains allow water to enter the boat in heavy weather.
When the cockpit contains water the drains are filled, and a pressure head forms in them. The pressure head will then cause water to flow back through the connected hoses aided by siphoning.
The bilge pumps have one-way valves, but if there is any debris in the water this causes the valves to leak.
Kind regards

05 October 2015 - 21:14
Join Date: 27 January 2011
Posts: 140

Hi Andrew,

it looks like Scotch Bonnet is in good shape again, after that amazing odyssey. I am impressed that you did not give up on her!

Christian 411/028

07 October 2015 - 14:28
Join Date: 28 July 2008
Posts: 79

One of our bilge pumps connects to one of the aft cockpit drains via a Y piece, down by the overboard discharge. I recall at the time the surveyor didn't really like this arrangement, but agreed it was Ok in this particular instance. This followed a long discussion on exactly the points that Lars raises.

To my mind there is one overriding issue here, do you find the current arrangements satisfactorily safe, irrespective if whether or not you can get a surveyor to agree / to the and get a concession?

At the end of the day, a lot of the regulations are based on hard lessons, e.g. 79 fastnet and whilst over time the origin and importance of some of these regulations can be diluted/lost, they are there for our safety, even if some of them appear to be a bit superfluous!!

10 October 2015 - 00:10
Join Date: 01 January 2011
Posts: 36

The history of the Rule is interesting, do you know Lars if it was exactly the element of our design which was found to be dangerous or were there more dangerous designs and we have been caught in the overall solution? In fact looking at our design I can only imagine gravity would stop the cockpit water rushing out as intended if the existing drain exits were immersed, and if that were the case and we installed new dedicated bilge pump skin fittings next to the current exits, we would potentially have similar problem with the ocean entering? Until starting this exercise I've been a fan of the effectiveness of the combination of our cockpit and drain size as well as the bridge deck, having filled up to the coamings a number of times I thought it drained very efficiently. So I''m not currently worried about the safety element of our design but am keen to hear from our S&S racers whether this caused them any problems with their safety audits and if they were obliged to change design? Many thanks all for your time and advice. Andrew 41/039

10 October 2015 - 18:13
Join Date: 02 January 2008
Posts: 1547

Dear Andrew
I would suggest that you have been caught in the overall solution. Siphoning may cause surprises, however, and to prevent this adding shut-off valves on the bilge pumping hoses would eliminate this danger altogether. The valves should preferably be close to the pumps, so the operator easily can open and close them.
He will certainly notice if he tries to pump against a closed valve.

Suggest you discuss this with the safety auditor. Pls note that this is just loud thinking from my side, will not back you up if he does not agree
If you have electric pumps they have no feel for high back pressure, nor for siphoning, and adding a valve would need special precautions and instructions.

Another thing you could do is to time the cockpit draining time. The European Recreational Directive requires that a cockpit filled to the coamings drains in maximum 5 minutes to a water level 0.1 m above the cockpit sole.
If you need to speed up this, particular attention should be paid to eliminating possible inlet restrictions or just sharp edges where the drain begins.
Pls note that there is a big difference in draining time if the exits are above or below the water surface. It can be remarked that if there is a big seaway and heel this is likely to throw out much of the water right away.

If you are required to move the bilge pump exits it is suggested that you check if they can be on the transom.
Kind regards

12 October 2015 - 12:23
Join Date: 02 February 2007
Posts: 202

Hello every one.
This is an interesting subject! I am surprised - to say the least - that no one speaks about the way to clean the manual cockpit bilge pump if it gets obstructed, or to change the membrane. (Still speaking of the 41). To my opinion it is almost impossible to do with the original arrangement, especially in an emergency.
I have personnaly cut a trap in the cockpit of Soeur Anne to access the cover of the pump, and think it is indispensable!
Kind regards.
Philippe 41/022 Soeur Anne

16 October 2015 - 10:22
Join Date: 01 January 2011
Posts: 36

Thank you very much Lars, we will submit to the safety audit with these possible solutions in mind, if the auditor requires. Philippe, thank you for raising such a good point, I for one hadn't thought of that. Do you replace the pump membrane periodically as a service item or only when signs of deterioration? Cheers Andrew 41/039

22 October 2015 - 18:09
Join Date: 02 February 2007
Posts: 202

Hello Andrew.
I do check the membrane every-year and , by the way, need to buy a spare.
Reading articles about trying to get rid of water entering in a boat due for instance to a valve failure one can notice that this water will come into the pump with lots of unexpected solid materiel, and absolutely needs to be cleaned at regular intervals, even if a filter exists.
I am really surprised to notice that this is not possible in a 41 without crawling uner the rudder quadrant... Forget about it in a emergency!
Really surprising indeed for such well designed yachts...

01 November 2015 - 09:33
Join Date: 02 February 2007
Posts: 202

A picture of the above.

05 February 2017 - 10:29
Join Date: 01 January 2011
Posts: 36

Dear Philippe and other 41 owners. I have finally got around to servicing our cockpit bilge pump and understand exactly the problem described. I am very reluctant to cut an access hatch and having looked at today think it impossible that the pump was accessed past the steering quadrant - certainly not an option fixing a problem at sea. But the pump must have been serviced in the last 40 years, how? The only possible way I can see is to dismantle the bulkhead at the aft end of the port bunk in the aft cabin.  Still not realistic in an emergency, perhaps cutting an access hatch in the bulkhead may work? But still doesn't explain how it has been done so far, there must be another way? Much appreciate any advice from someone who has solved this puzzle. Andrew  "Scotch Bonnet" 41/039

07 February 2017 - 08:19
Join Date: 02 January 2008
Posts: 1547

Dear Andrew

You could also consider cutting loose the panel where the cockpit pump is mounted, and reattach it with a flange covering the joint, or make a new overlapping panel for the pump. The connection should have easily opened fasteners which can not drop out. The panel could be hinged, provided the hoses allow the pump to swing out into the cockpit.
I wonder if during the build there was access through the helmsman's seat, but this route was then closed by some additional partition.
Kind regards

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