Laser Bailer Repair

Springs, not rings, give reliable function and allow use of broken bailers

Laser sailboat or dinghy bailers suffer frequent O-ring failure. LaserSmartParts stainless steel replacement springs cost £4.20 and are fit-and-forget; they will outlast the boat. No more racing with the chute down causing drag when you want it up, and reduced risk of damage when coming ashore. The more positive action also helps keep the bailer open when selected, so you will not have to take off the bung and tape down the rod. (recent rule change).

LaserSmartParts springs are easily fitted without changes to the bailer. Fitting these will save you time and money on an awkward and fiddly repair; they will also work with broken or weakened pivots, saving the cost of a new bailer.

Customer endorsements

You can read endorsements from customers who purchased through Ebay here.

Comments include

• 'if you have a Laser, get a set of these'
• 'now fitted on both our Lasers'
• 'more orders coming'
• 'every Laser sailor should have one'

and those with broken bailers wrote

• 'saved me buying a whole system'
• 'worked like a charm'

Rules

ILCA Rule 13 has been changed for 2010 to include the following words- 'The builder-supplied O-rings may be substituted with non builder-supplied alternatives provided the basic function of the bailer is unchanged.' This change was requested by my customers because of frequent O-ring failures.

The Laser Forum suggests this method for replacing rings and achieving the smoothest hull form 'Remove bailer and silicone sealant, replace rings, set bailer in new sealant flush with hull and allow to set for 24hrs. Tighten screw'. Unless you carry a set of rings and sealant with you, you will have to make a visit to your boat without being able to sail it. If you live near your boat, it's a nuisance; if you are far away, it's costly and time consuming.

Background

Early Movevirgo bailers had weak pivots and the front part often broke if the bailer chute was down and hit something. The chute was often down because the rings had broken! After 25 years, at around boat number 160000, the opportunity to improve it radically was lost when the bailer was retooled by Nautos with only minor changes. The pivots were strengthened, which meant that the ring hook had to move further from the pivot. This results in the ring getting stretched even further beyond its elastic limit. The pivot clearances were also reduced, changing it from a free moving pivot to one with inherent friction.

So we now have a design with pivot friction and an even more over-stretched ring, which results in the chute not closing fully after a short period of use.

What's wrong with O-rings

O-rings are designed as piston seals, to be fitted into a groove in a piston by stretching them 10-20% just once for a few seconds during fitting. They are formulated for resistance to wear and chemical attack. They are not formulated to be stretched to approximately twice their size frequently. This causes 'permanent set', reducing the elastic force, and they break at the weak 'weld' point where material meets after flowing round both sides of the mould. They should never have been specified.

If you buy O-rings from your local hardware store, they are likely to be Nitrile rubber (cheapest and best for resistance to oil and fuel), whereas Neoprene (best for resistance to ozone and sunlight) or EPDM (best for resistance to water) are the best choices. The hardness is also likely to be 70-80 Shore; 50 Shore is probably best, but you won't be able to buy those. If it's not right, it'll last even less time.

How the springs work

The positive spring action maintains the 'over-centre' action keeping the chute down, making an accidental closure less likely, and helps to pull the bung back into the hole when you close the bailer.

The springs act on the chute stop, not on the hook close to the pivot. Hence the force applied is much smaller. The upward force applied on the fulcrum of either the cam axis, (with the chute up), or the cam foot, (with the chute down), means that there is always a downwards force at the pivot.

Hence the pivot strength is not important, and bailers can be fully functional with weakened or one broken pivot. The pictures show my Movevirgo bailer; the right hand pivot has a typical break, one spring is fitted on the left.

I have since added the right hand spring to increase the force holding the chute down. This is shown on the video below.

Test data

Rubber rings apply an initial force of 1300g (2.85lb) each to the hook with the chute down, 750g(1.65lb) with the chute up, but these values decrease rapidly with use. LaserSmartParts springs apply only 330g(0.70lb) to the stop with the chute down, 200g(0.45lb) chute up.. Both springs apply 400g with the chute up, which is 2-3 times the Nautos friction force, hence the chute will always fully close, even with sand around the pivots causing extra friction.

To close the bailer chute, a force of 1.7Kg (3.6lb) must be applied to the operating rod, hence accidental closure is unlikely. This is similar to new O rings, but is maintained for life.

The spring material does not exceed its elastic limit. 1000 operations caused only light polishing of the bailer body as the spring end slid on the body when it was deflected.