In the Sail Fast, Live Slow weekly newsletter we’re building up an A-Z of yacht maintenance tips. I thought it’d be handy to have them all in one place, so here they are 🙂
A is for…
- What is it: A special paint applied to the bottom of a boat, usually made of cuprous oxide (or other copper compounds).
- What’s its purpose: To slow the growth of sub aquatic organisms that attach to the hull and which can affect a boat’s performance and durability.
- Maintenance tip: This article gives advice on frequency, how to choose the best type of paint, the tools you’ll need, what you’ll need to be wearing (it’s a messy job!!) and how to go about it.
- More information: Copper isn’t great for the environment so some countries are threatening to ban the use of copper in antifouling by 2020. What happens then?
- What are they: Sacrificial anodes are chunks of zinc, aluminum or magnesium which are fitted to a boat underneath the waterline.
- Why are they needed: Their job is to help prevent corrosion of expensive metal boat parts (prop shaft, engine) by sacrificing themselves to be corroded away first.
- What causes corrosion: When two dissimilar metals are in close proximity underwater a constant stream of electricity passes from metal with a higher value to metal with a lower value (in the Galvanic Series). The result: the more active metal (confusingly the one with the lower value) will corrode first. When an anode is fitted, it becomes the most active so gets eaten away first.
- Maintenance tip: Anodes need replacing when they’re about 1/3 degraded (which in practice usually means annually).
- More information: Watch this guy replace his anodes underwater, read more about marine corrosion and what to look out for and, for the data enthusiasts among you, take a look at a Galvanic value table.
B is for…
- More detailed maintenance tips are covered here.
- How to choose a marine battery: this video gives a nice explanation of the things to consider as does this article.
- Lithium-ion vs AGM is covered here.
What are they? They’re one of the most essential pieces of hardware on any sailboat. Lines run through blocks to create purchase systems or change the direction of the rigging or line. Take a look at some here.
Block and traveler maintenance isn’t something that springs to mind as the most exciting of projects, and for many of us this may be something that gets put to the bottom of the to do list. According to this article by Harken, it really shouldn’t be.
C is for…
What are they? Chainplates are metal plates (usually made from stainless steel) used to attach a shroud or stay to the hull of a sail boat.
What’s their job? Chainplates transfer load from the rigging (the lines, cables etc which support the mast) to the deck and the hull.
Where do you find them? Most standard chainplates are found amidships bolted to the hull, cabin sides, or to a bulkhead. They pass from inside the cabin, up through the deck, usually through a chainplate cover and then bolted to the deck. The job of the chainplate cover mainly is to stop water getting into the cabin.
What can go wrong? Two things mainly. Due to the loads inflicted on them from the rigging, eventually they’ll start to leak. When water starts to seep in corrosion is unfortuantely inevitable (mainly due to the mix of materials; stainless steel, fibreglass, salt water). Chainplate failure can be catastrophic and is one of the leading causes of dismasting on older boats.
How will you know something isn’t right? You’ll see evidence on the hardware (corrosion) and perhaps watermarks around their installation in the cabin.
How do you maintain them?
- Visual inspection: This article gives some practical advice about how to visually inspect them. He recommends to do this annually.
- Rebedding: In this article the author documents and photographs the process he went through to rebed the chainplates on his yacht after they started to leak.
What are they, and what’s their job? They are valves which ensure fluids (and in some cases also air) only flow in one direction. See some examples of what they look like here.
Where do you find them? They’re often found in water, sanitation and sewage systems. Sometimes in certain applications, they can also be found in fuel and exhaust systems. They come in two main types:
- A swing check valve which has a little one-way gate system which shuts if liquid tries to flow in the opposite direction.
- A spring-loaded disc value, which is located in the fluid stream. Pressure from the fluid compresses the spring, pushing the disc back into the valve body and opening up a path for the liquid to flow around it. Liquid which attempts to go the wrong way seals the valve shut.
What can go wrong? Check valves have a habit of becoming lodged (open or closed) when they’re used infrequently, for instance, if you have them in your bilge pump setup. It’s therefore vital that you can access the value in order to clear it out.
How will you know something isn’t right? Common signs include: noise (water hammer), vibration, reverse flow, sticking, leakage, missing internals, component wear, or damage.
How can you maintain them? There’s not a huge amount you can do in terms of maintenance. The main thing is to check that you have the right type installed for the job. This article explains what you need to know (and it’s where the above symptoms came from).
Some words of caution: Check valves may prevent some electronic bilge pumps from working. Imagine a situation where you stop pumping and valve closes. When you try to start pumping again, the standing water on the downstream side of the hose might be too heavy and prevent the value from reopening. The pump will run and make turbulence in the water however it won’t actually be pumping any water out. Very disconcerting!
For this reason they’re not recommended to be used in a bilge set-up, a prefered solution is a diaphragm pump as described in this article. These types of pumps have the added benefit of completely emptying out your bilge leaving no leftover water.
What is it, and where do you find it? A boat’s propeller shaft is supported at both ends. At the inboard end it’s held by a coupling attached to the transmission. At the outboard end (the bit in the water) it’s supported by a fluted rubber tube called a shaft, or a Cutless bearing. This consists of two main parts:
- An outer circular shell made from naval brass or a nonmetallic composite.
- An inner tube made from a hard rubber-like substance called nitrile.
What’s its job? It supports the outward end of the prop shaft and ensures that seawater can be sucked in and easily passed to the shaft in order to lubricate it. The inner tube has ‘valleys’ which are designed to improve water flow and to flush away any grit or other hard material that might wear on the shaft.
How will you know something isn’t right? You’re likely to hear rumbling or feel vibration that increases gradually over time.
What can go wrong? Although they’re pretty durable, bearings do wear out and need to be replaced to avoid vibrations or worse shaft damage. Premature wear can also be caused by doing a lot of motoring in very shallow water with a sandy bottom as more silt, rocks etc will be sucked up into it. Other possibilities include a misaligned drive train as well as a bent prop shaft, as this will cause uneven pressure and accelerate wear.
How do you maintain it?
- How to check a Cutless bearing: This video gives a nice short and sweet explanation.
- Replacing a Cutless bearing: If you’re feeling brave and want to give it a go yourself, this is the best article I could find which explains what’s involved. Although he does appear to spell Cutless with an “a”? I couldn’t find a video decent enough to share.