This page is for owners and/or builders of all Farrier designs, and is intended to be a reference page for many matters such as plan updates, regular maintenance, frequently asked technical questions, and various notices. Further information, open discussions, and a good way to get questions answered from both owners or Ian Farrier is also available on the new F-boat Forum:

There is also a forum for owners and/or restorers of the early Tramp/Eagle design. Details at:

Plus a forum for the original Trailertri designs:

First introduced in 1985, this trailerable trimaran quickly became a seminal boat in the world of multihull sailing. Designed by Ian Farrier, a Kiwi who emigrated to California (by way of Australia) with the specific goal of perfecting his concept of a production-built trimaran with folding amas, the F-27 is both an excellent high-performance coastal cruiser and a competitive one-design.

The following are downloadable Adobe Acrobat PDF documents (just click on the highlighted title).

Build to Plan! One of the biggest problems over many years has been the few builders (both professional and amateur) who do not follow the plans. Farrier designs are very well developed and tested, and leaving out a particular reinforcement, or placing it incorrectly, or deciding something is not really needed can cause many problems.

Having been involved with production boats for many years, where a rate of two boats a week is not unusual (six in the case of the original 19′ Tramp), it soon becomes obvious that every boat has to be built methodically, and with consistent well defined procedures, so that it is right when it comes off the line. Otherwise one can quickly generate a mountain of problems.

I have therefore always spent a huge amount of time on each set of plans, constantly checking, and making sure every aspect and scenario is covered. This is why I currently only have 5 basic designs available, which are all very well developed designs having been constantly improved and refined. Follow the plans, and the checklist style instructions, and one cannot help but build a near perfect and trouble free boat

Beware also of those with little experience or qualifications who may want to redesign your boat, as more problems have arisen from this than any other. Should you let Joe Whatshisname redesign your boat, then please call it a ‘Whatshisname XX’. If things don’t work out quite as planned, then be sure to call Joe to fix it. Such re-designers should do their own designs, under their own name, rather than put someone else’s reputation at risk. If something goes wrong they can just walk away, leaving the unfortunate designer (the one with his name on the boat) to take the heat.

In fact any builder changing things or not following plans without first checking with either owner or designer is ‘experimenting on owners’ at its worst. The owner has paid for and expects to get a certain boat, based on the designers reputation. In the case of a completely new and untried design, the owner is aware that some new and experimental features will probably be incorporated, otherwise there would never be any progress. But the owner can at least look at the designers track record with new innovations, and make a judgment if it is worth a punt.
But if any builder then secretly alters or omits things then everything changes, the owner is paying for something different from what he thinks he is getting, while the designer’s reputation is being put at risk. Design changes can of course be made, but the correct way is to consult with the original designer first. Many good ideas and improvements have come this way, but there are also many that have been ruled out, and possible problems prevented.

F-boat maintenance Guide – A regular maintenance checklist of important items to check

Beam and Folding System Care – important notes and advice on the care and maintenance of the beams and folding systems for all Farrier designs.

Beam Compression Pads and their Care – all you ever wanted to know about compression pads

F-31 Float Bow Collisions – things to check, and how to minimize any damage

Helpful Hints – from the latest Sailing Manual

Check Your Chainplates for Crevice Corrosion – Two instances have now been reported of F-27 chainplates breaking off at the deck on the main cabin, causing the mast to fail. This can be caused by crevice corrosion where stainless steel can rapidly corrode and fail if water is present, without any oxygen. A good detailed description can be seen at;

Chainplates that pass through the deck are always difficult to seal properly, and leak prone, so water can get in. If it is then possible for it to collect alongside or around the chainplate then corrosion can be rapid until the chainplate fails around the deck area, even though this is where it is actually the strongest.

Thus it is important to check your chainplates regularly, and if any possibility or evidence of a leak exists then it should be fixed immediately. This affects all boats, not just F-boats.

This risk of corrosion is always there with any stainless steel, including rigging wire, and it is important to regularly check for such corrosion, and eliminate any areas where water may collect.

Carbon chainplates only are now used on all my latest designs, along with synthetic rigging, plus are options for earlier designs, and these will eliminate any such problems.

F-24 Beam Bulletin – cause and repair of cracks that can develop at inner ends of some early F-24 beams

F-31 Beam End Repair– repairing damage that can result from a float bow collision

F-31 Bolt Pad Repair– repairing damage that can result from a float bow collision

Rudder Fences – these can help eliminate any steering problems due to rudder ventilation at very high speeds

F-27 Rigging and Setup Guide (extract from original F-27 Sailing Manual)
F-27 De-Rigging Guide

F-27 Double Spreader Rig Modification
Eliminates inner forestay and makes rig more foolproof

F-27 Trailer details – trailer worn out and need setup details for a new one?

Docking While Folded – Farrier trimarans are designed primarily for trailering, but they can also be folded and easily docked in a conventional slip. However, if left for an extended period, growth on the float sides can become a problem.

An excellent solution is the HydroHoist, which lifts the folded boat completely out of the water, by pumping air into two supporting pontoons. This takes just a couple of minutes. The boat is then high and dry, avoiding any need for bottom paint. Cost of the HydroHoist can even be recovered by the savings in bottom paint, and the boat will have better resale value. Details are at www.boatlift.com.

Another choice is the air lift dock at (photo on FAQ page): http://www.airdock.com

However, always be aware that folded stability is limited on larger models, and care must be taken while motoring or when docked while folded as per:

Don’t Remove Beam Bracket Bolts: It is important to note that the Lower Folding Strut beam bracket bolts are not removable and any attempt to remove may result in the bolt head itself being twisted off.

These bolts pass through carbon fiber reinforcement in the beam, and the stainless steel bolts should be insulated from the conductive carbon fiber. But, it is also structurally very important that the bolts are not allowed to bear directly on the relatively brittle carbon fibers, and any such contact should always be cushioned by an epoxy glue.

Thus these bolts are locked in place for the life of the boat, and the only maintenance should be a regular washing in fresh water.

Daggerboard Case Cheek Block – the best way to fit

Daggerboard case cheek blocks are best secured in place by machine screws, acting as studs as shown. Pan head screws are not secure enough, and leaks here can be an ongoing problem.

Comments: Problems may have been caused in this area on some boats by the use of self tapping pan head screws around the perimeter of the Cheek block mounting plate which do not hold very well in thin fiberglass. This cheek block can see some very high loads at times, and self tapping screws are not very good at resisting such loads. Worse, when such screws are removed to check block, the threading in the fiberglass is not very stable, and can be easily damaged to where the screw will not bite when put back in place. Thus one has a guaranteed leak.
If these are machine screws tapped into fiberglass, then this is better, but still too weak and prone to leaking.

The only correct way to secure this check block plate to thin fiberglass like this is to use machine screws, tapped into the fiberglass, with the head on the INSIDE of the case, so that studs are formed inside the boat, which then take nuts. This makes the plate easily removable, and secures it to the case side in the strongest possible way – it is thru bolted, and there’s no chance of stripping the threads.
This method is used on the F-33 as shown above.

If there are problems with an existing boat, then remove all screws, drill the hole out to the next size up tapping size, and tap to suit machine screws. These will hold better than self tappers, but over time have the same problems – the holding power is limited and the threads are easy to damage. Studs are the only right way.

With existing boats, it may be possible for someone with small deft fingers to insert pan head machine screws from the inside of the case via the check block hole, but this is difficult to achieve.

Another solution is to insert some threaded rod, and epoxy a nut to the rod on the inside, which should be easier than inserting a machine screw from inside the case. Then wind rod back out until nut beds itself on inside of case. Allow epoxy to set and you have studs. Bit of a fiddly job, but definitely doable.

It is also very important to protect from corrosion in this area as per my standard procedures. The cheek block should be bedded on a sealer (silicon or 5200), and all stainless screw heads, nuts, washers etc. should be insulated from the aluminum plate by a nylon washer where possible.

Then, when fitting, make sure the sealer used squeezes up inside every bolt hole to insulate bolt from aluminum.

Modifying Outboard for better Reverse Thrust – an article by Bob Critchely

Multihull Safety Issues – an important issue as there are many misconceptions.

Wiring Diagrams
F-27
F-24
F-28
F-31

Owners of F-28s and F-31s built between 1997 and 2001 should be aware that Corsair used buried wiring in the cabin roof of these models, and care should be taken when adding deck fittings, so as not to drill through said wiring. I requested Corsair to supply maps of the wiring in May 2002 but they have never done so.

Sail Plans – Check on link to download.

F-24 Mk II sail plan updated December 28, 1998

F-27 1996 model sail plan (Also formula sail plan)

F-28 sail plan updated December 28, 1998

F-31 (Sept 2ndhttps://f-boat.com/wp-content/uploads/2019/10/F-31RSail.pdf, 1999 on) and F-9R/F-31R sail plan May not apply to the Corsair 31, as now being manufactured by Corsair Marine

The above files are in an Adobe Acrobat pdf format, which is readable by any computer platform (Mac, DOS, Windows etc.), but to read you must have a copy of Adobe Acrobat Reader for your system. This may already be on your computer (included with browser) and it may open file automatically after download. If not present, it can be downloaded free of charge from Adobe’s Internet site (http://www.adobe.com/), or from Compuserve or AOL. Netscape Navigator handles PDF documents best.

New Boat Delivery Checklist
Taking delivery of a new boat? Here are some things to check – useful also for a used boat

Used Boat Guide
The various versions and what to look for.

Trailertri 680 and 720 – Complete plans for the Trailetri 680 or 720 are now available on CD for refurbishment purposes only. Contact Us for more information.