Friday 13 December 2013

Check Your Fuel Filler Cap O-ring Seals

Diesel or Petrol fuel filler caps are often located on an exposed area of horizontal deck or cockpit floor, particularly on sailing yachts. I recently performed a pre-purchase survey on a Nauticat Pilothouse Ketch, located at Woolverstone Marina, Ipswich. The image below shows the fuel filler cap & sealing O-ring of the starboard fuel tank of this motor-sailer. Note that the nitrile rubber has aged & hardened, resulting in numerous circumferential cracks in the O-ring, each one allowing moisture into the fuel tank. Additionally, the part of the fitting that was set into the deck was poorly designed, allowing sea water, rain water or dew to collect in the rebate that runs around the opening hole.

Fuel filler cap seal on sailing yacht
Typical deck-mounted filler cap

Prior to this discovery and during the survey of the rest of the vessel's fuel system, I had carefully inspected the glass-bowled primary fuel filter of each fuel tank. I noted that the colour of the liquid inside the starboard tank filter suggested that there may be water in the tank.

These were the recommendations made in the report:


1. It was found that the primary fuel filter for the starboard fuel tank had a layer of water at the bottom of the glass bowl. It is RECOMMENDED that any water in the bowls is tapped off from the primary filters for both fuel tanks. The fuel tanks should also be drained off and the contents checked for water contamination.

2. The two fuel tanks are refuelled via separate filler caps located on the port and starboard side decks. They were appropriately labelled with the text ‘diesel’. It was found that the O-ring seals that seal the filler caps were heavily perished. It is RECOMMENDED that the filler cap O-ring seals are replaced.

The new owner of the Nauticat was able to drain off two buckets of water from the starboard tank! He was lucky that there was no evidence of diesel fuel fungal growth in the tank as disel fuel with a high moisture content tends to encourage their growth.

In the UK, you can obtain new O-rings through Screwfix: www.screwfix.com/metric-o-ring-set You might not want to purchase a whole set of varying sizes just for this purpose, although it would be money well spent!

Monday 2 September 2013

Check Your Seago 150 and 175 Lifejackets

The older Seago 150 and 175 lifejackets have been subject to a recall notice for a few years now, but I'm still finding ones on boats that I survey. The first thing that I do when I discover that the item might be faulty is to remove the cylinder and this is why the jacket in the photo doesn't appear to have one.


Recall notice on Seago 150 or 175 Lifejackets
Check the date of manufacture of your Seago 150 or 175
The lifejackets are marked with the manufacturing date on the reverse of the white labels found sewn into the lifejacket below the inflation system. The lifejackets affected by both recalls all bear the following marks:
IV/05, I/06, II/06, III/06, IV/06, I/07 and II/07
If you check yours and find that you have one or more  that have a date of manufacture noted above, remove the gas cylinder from the inflation system and telephone Seago on 01825 873632.

Tuesday 4 June 2013

Gas Locker Drain: A Water Trap Could be a Death Trap

Thankfully I don't come across this defect very often. It is probably something that many owners would never notice as everything looks as though it is in good order, although in the photo below, the hose should be of the reinforced type and two hose clips should be used if the skin fitting allows this.

Yacht Survey, Gas Locker Drain
Gas Locker Drain Hose with Water Trap in U-bend
It isn't entirely clear from the photograph, but the drain hose from the boat's gas locker has a bend in it that can trap water. If water were to enter the locker, it would find its way into the tube where a small amount would be trapped. Similarly, when the boat is healed over on a close-haul, seawater could easily enter this drain. Until the water is able to evaporate, the locker drain will effectively be blocked, preventing any leaked gas from escaping harmlessly overboard. Cooking gas or LPG is a very 'searching' gas and will seep through gaps that might normally be airtight. On this vessel, it would have entered the aft heads and then into the bilge, with potentially devastating consequences.

This simple but important defect was discovered on a standard Insurance Survey on a 33' sailing yacht. Owner's are usually reluctant to have these surveys done as it is often considered that the report is purely for the benefit of the Insurance Company. The above example clearly shows that the vessel's owner can gain significantly from having a thorough survey performed on their craft, even if they think that they know their boat inside-out.

Tuesday 19 March 2013

Domestic Plumbing Hardware Used on Boats

It might be perfectly acceptable to use PVC plumbing fittings on the vessel's fresh water system, but if one was to fail, I would still be rather upset if the contents of my water tank were to sit in the bilges for some weeks whilst un-attended on her mooring. However, during my survey work I often come across more serious situations like the one shown in the photograph below. It's not uncommon for an owner to search amongst the shelves of a chandlery, looking for a marine-grade fitting of a specific size. After a frustrated search he finds what he's looking for, but neglects or forgets to consider the items' suitability for the application.

In the situation shown in the photo, a domestic plumbing fitting has been installed in a location that is below the waterline. The hose and fittings (un-reinforced hose and with single clips) are for the generator exhaust coolant outlet on a 51' motor cruiser. Even above the waterline, this situation could cause significant ingress of water if the relatively weak fitting were to fail: The generator's coolant would be pumped directly into the engine room and is also in close proximity to the vessel's batteries. In the situation shown, the hose attached to the 'un-reinforced PVC fitting' would drop down, allowing water to flow into the boat.


In this example, the skin fitting is about 12 inches below the waterline and the internal diameter of the hose is about 1 inch. For a length of hose such as that seen in the photo, the resulting flow rate will be around 9 gallons or 4 buckets of water per minute. Of course, the vessel's pumps may be able to handle this amount, but in this case a few low cost preventative measures would minimise the chances of this scenario occurring.

For advice on the installation of your vessel's skin fittings or through-hulls, contact fieldhouse-yacht-surveys.com
PVC skin fitting on yacht generator exhaust system
Generator Exhaust System