Fitting Out A Cherub.

Disclaimer

This document is compiled by an amateur, not a professional. It has been compiled in good faith, but almost certainly contains errors and inaccuracies. "Best practice" also changes frequently with changes in technology and materials. None of the procedures listed are guaranteed to work, and some or all of them may be hazardous. If you feel unable to take responsibility for your own actions and errors without resorting to the legal profession then you are advised not to read it, let alone build anything based on information here. In any case you are advised not to use epoxies and composite construction without someone experienced in the materials to contact for advice
Gear & Fittings Installing a Bowsprit Building a Rudder Gantry Building a Rudder Stock

Rigging

Keep It Simple.

There is absolutely no need for complex controls on a Cherub. The modest sail area means that the rig is kept powered up most of the time, and spectacular rig controls only distract from the serious business of sailing the boat as fast as possible.

Rig Tension

Most modern Cherubs use loads of rig tension - enough for many SMOD boats to just fold up! 300lbs plus on the shrouds is not unusual and often a lot more. The primary reason for using lots of rig tension is because the crew is on the trapeze. If you have 100lbs of rig tension on the windward shroud, the leeward shroud just slack, and the spreader holding the mast straight - as might be the case on a sit out boat - then when your 140lb crew gets out on the trapeze the windward shroud will go slack and there will be 40lbs tension on the leeward shroud, with its spreader pushing the mast mid section up to windward, depowering the whole rig. This is slow! Consequently most boats start with 200lbs plus of rig tension. On the other hand you have to be sensible with older boats. If I put the 400lbs odd tension I use on the foam sandwich and carbon reinforced Bistro on my 3mm plywood topsides 1972 Farr then the poor old lady would just bend up and probably break. A good clue is to watch the foredeck as you put the rig tension on. If the boat is distorting the gunwales will spread between the mast and the forestay, and the foredeck will distort and go into humps and hollows. You have no foredeck? Another reason why its a bad idea to lose it! Obviously extra rig tension also tightens the jib luff etc, but I suspect that by the time you've got enough tension to make the spreaders work right with the crew bouncing on the wire the behavior of the jib luff has ceased to be an issue. Its good to have the shroud anchorages as far outboard and aft as possible to reduce the peak loads when nosediving etc, although obviously you also have to be able to let the boom out.

Standing Rigging.

Cherub rigs need to be strongly supported at gooseneck height. The short boom and big roach means there will be a lot of kicking strap load which will try very hard to bend the mast sideways and dump all the power. All fittings must be stronger than you think. Everything should be bolted on, and attached to something secure. If you have the slightest nagging doubt about something it will break. Cherubs seem to put phenomenal loads on fittings, and most especially anything to do with lower shrouds.

Gooseneck Level Control.

The anchorage point for the lowers needs to be incredibly strong T terminals are the only choice in an alloy spar. Any kind of rivet will either snap or pull through the mast. A plateround the mast front like an RS800 is about the only alternative. On a carbon mast T terminals are also OK, and another good alternative is s/s rings bonded in with a lot of carbon. The other end should be absolutely rock solid, bolted, and ideally putting its anchorage in compression - e.g. running round the gunwale. A well monted anchorage loaded in sheer will also be fine, but any trace of tension and it will just peel off.. On a foam sandwich boat a stainless steel ring firmly located with a lot of unidirectional carbon is a good solution. On single spreader rigs you normally need what we in the UK call a prodder - a strut to gooseneck height from the foredeck.They do, of course, preclude self tacking jibs. On twin spreader rigs the extra control of the mast further up seem to make these less essential, and it seems to be possible to get away without them, especially as a prebent rig resists mast inversion - one of the most common causes of failiure (other than fittinsg breaking!). An alternative you will see is to have the mast supported by "rigid" lowers - struts to the gooseneck to replace lowers, which at the cost of a bit more windage lock the mast very rigidly. Gavin Sims currently has a post to gooseneck height supported by rigid struts, with the mast stepped on top. The twelve foot skiffs use a similar arrangement without the struts - just a post of truly massive construction integrated into the hull. This weight goes into the hull weight total and is towards the middle of the boat so its quite acceptable on a new boat. The loads at gooseneck level are magnified by this arrangement as the rest of the rig doesn't assist, so don't underestimate the loads involved. Your editor did back in the late 1980s and put a mast through the foredeck twice in 3 days.

Single Spreader Rigs

This was the most common setup prior to the extra sail area introduced in 1997 and will still be found on older boats.
Two shrouds, one set of spreaders, lower shrouds to gooseneck height, and prodder - used as much to induce pre-bend as anything else, so needs to be strong in tension as well as compression. The lowers don't need to be adjustable, but you need an easy way to tension them. A kevlar/spectra/other high tech rope lashing is as good as any, very cheap, and very effective. Kevlar 's tendency for unannounced failure is always a worry though. Although in theory raked back spreaders lead to better gust response in practice on a Cherub you are hunting for power much of the time, especially with a pre 94 rig, and so spreaders would be neutral or slightly angled forward to keep the lower mast straight in conjunction with the prodder, leaving the top mast to flex and provide what gust response their is. This is probably still the best solution for a boat with an alloy mast. Tall alloy masts with twin spreader rigs seem generally to have too much weight aloft and performance suffers upwind. I think Andy Paterson was the only person to manage a competitive two spreader alloy rig. The spinnaker halyard can be appreciably above the hounds. You can probably go to about two feet or 60% safely, although this depends some on the mast section. The most extreme was probably my rig seen on earlier picture of 2641 on this site, but I had a particularly solid mast section.

Twin Spreader Rigs

With the greater sail area since 1997 and the much lower weight of carbon spars these are pretty much universal on newer boats. A typical two spreader rigs with masthead upper shrouds will have quite a lot more wire. The most common setup is to have conventional spreaders to a conventional height, plus "D2" or checkstays running from the shroud plates to the root of the spreaders. This locks the bottom of the mast fairly rigid. The masthead shrouds are actually diamond stays, normally running through spreaders on the hounds then through the main spreaders, and then back to the mast around gooseneck height. These shrouds will reduce sideways bend considerably, and also support the tip of the mast for a masthead spinnaker. You can also use them to induce considerable pre-bend in the top mast, similar to a skiff/49er rigs.
There is a lot of variation in the staying arrangements. Most UK rigs use shorter upper spreaders, with the caps attached to the lower spreaders about halfway from the end to the root. The cap spreaders are heavily raked aft, introducing greater or lesser amounts of prebend, according to your sail cut. Most prebend is seen on the Andy Paterson designed Superspar/Caws rigs, and least on Batt based rigs like Dave Roe's and Robin Russell's. At the lower spreaders the caps are set with relatively little deflection so that they have little effect on mast bend. Some rigs - noticeably Andy Paterson's and Robin Russell's have the caps pulling the mast forward at the lower spreaders and the shrouds pulling the mast aft and acting against the pull from the caps. This has the effect of locking the mast to a certain extent at spreader height and can mean that you can do without the check stays and all their extra windage.
By contrast my New Zealand designed C-tech rig has a lot of aft rake on both sets of spreaders and full length spreaders at the hounds. Both sets of spreaders are well raked back, and the check stays are vital, taking at least as much tension as the shrouds in order to hold the mast straight. This holds the mast very firmly with a lot of control of the prebend, which is largely above the hounds.

Over Rotating Masts - Wing Masts

It hasn't been done in this country for many a year, but in Australia a couple of boats have recently been seen with over-rotating semi wing masts, based on NS14 sections. This is a classic example of the wheel turning round, as such rigs were used in the early 70s, although the masts were spruce and balsa then. Such spars ought to be effective if you get them right. Supporting the bigger UK kites, especially masthead ones, could be a challenge, but it can be done - Alex Vallings of C-tech Spars in New Zealand has recently won an R Class Championship with a mast which has the tip supported by rotating spreaders. He tells a story of spending some time with a model made from broomstick and string working out how everything needed to be set up to avoid wires clashing as the mast rotates. In 2002 we permitted a mast with a greater chord than previously provided the area is measured in, and there is probably a performance benefit to be gained for a project with a considerable development curve. Bethwaite is good on the subject in "High Performance Sailing".

Necessary Gear

· Main sheet
· Jib sheet
· Spinnaker Sheet
· Spinnaker halyard/retrieve
· Pole or Bowsprit/retrieve
· Kicking strap
· Cunningham
· Outhaul

Optional Gear

· Jib slot (barber hauler etc.)
· Prodder adjustment
· Main halyard

Unnecessary Gear

· Jib halyard
· Adjustable standing rigging
· other trendy trivia

Mainsheet.

There are two popular mainsheet systems. One is to have a central post (like a hoop, but lighter and cheaper), and the other is to have a fixed bridle at the transom which joins the mainsheet at boom height. In either case the mainsheet is led to the centre of the boat, has a ratchet block, and if there is a jammer it should be arranged so that the crew can use it from the trapeze. Very often the mainsheet is lead from a ratchet block on the boom direct to hand, and not to the floor. This is definitely the preferred setup if the crew will take the mainsheet on the beats. This may sound weird, but try it!

Jib sheets.

They can be led to anywhere convenient, with a jammer that can be freed and jammed from just about anywhere in the boat, since the crew will be trapezing right at the back of the boat on windy two-sail reaches. Inboard from the shrouds is a good place, out of the way but accessible. Continuous jib sheets are popular. Sheets should be long enough for the crew to be able to fully free the sail from on the trapeze at the back of the boat. If they are too short you will regret it!

Self Tacking Jibs

The sailing techniques are different, especially upwind, where you don't just leave it and forget it - see the heavy weather sailing article. They're best done with a track and roller bearing car - the smallest available say Frederiksen 020. The track is bent to slightly less than the radius from the tack of the sail to clew. The sheet is 2:1 under the deck, with the final lead exiting and going round a cheek block just behind the sail tack. The track is bent in one plane (forward but fitted angled up slightly , i.e. the ends are slightly higher than the middle). The ends are fixed in foam/carbon supports, and one screw in the middle into the mast step structure. It's a very good idea to have two bolts in the track at the ends, because if the track comes undone you will not only break the track, but also lose all the bearings out of the car. You also tend to hold on to the track launching, so it needs to be prettu substantial. The track is angled/bent/fitted so that heavy sheet tension will pull the car to the centre of the track in no wind.
The wind pressure in light winds and low sheet tension is enough to move the car to the ends of the track. In stronger winds it also works fine, but needs rubber stops at the end of the track.. In general people don't seem to have stops for sheeting angle, so it would be wise to have numbers or marks on the track. Sheet tension varies the leech tension as required. The pulley on the track is suprisingly tricky. It wants to be as light as possible for light airs, but it takes a lot of abuse when the jib flogs. A block with plastic cheeks will waer theough quickly, and it takes quite a bashing so should be strong.
Most people have a swivel jammer not unlike a mainsheert jammer for the jib, and a single sheet. This is probably neatest. An alternative would be to split the sheet to each side and run them to a conventional sort of location. In any case remember the crew will still need to play the jib sheet on two sail reaches and while tacking. And just because there's a two to one purchase don't use a thin rope. The crew needs to be able to use the jib sheet to pull themselves back to the boat if you teabag. Given a 4mm line and a cold day this just doesn't happen. Trust me in this!
The clew position on the sail is crucial. You'll probably end up getting the sailmaker to change this once the setup is all sorted out. Mutiple holes on the jib clew give you a choice of slot angle/twist in the jib against the sheeting angle.
It can be a good idea to add backing lines. These are a couple of light lines running from the car to the shrouds on each side, long enough not to restrict the normal movement of the jib. If you need to back the jib for some reason then pull on the line. To heave to between races hook it over something handy! But if you find they get snagged take them off, they're not that vital!

Spinnaker sheets

These are invariably continuous. Ratchet blocks are essential, and the same comments on jammer location apply. The turning point for the spinnaker sheets will never need to be aft of the mainsheet, and may be as far forward as the shrouds with some sails. Not everyone has jammers, but I find them handy for keeping the sheets in the boat upwind, and for quicker hoists in light airs (keeping the sheet jammed). Mind you if you hoist with the sheet jammed in 25 knots you'll swim. Most boats with snouts have a hollow in the gunwale line between the snout and the shroud. This makes spinnaker sheets especially prone to be washed into the water on the beats. Andy Paterson has small "hooks" made from very flexible polyethylene on his gunwale. Flick the sheet onto this and it stays on board, but they're too soft and flexible to snag anything or damage the spinnaker. Again sheets should be long enough for the crew to be able to fully free the sail from on the trapeze at the back of the boat.

Other Spinnaker Gear.

The adoption of asymmetrics has simplified spinnaker handling a lot. There is no spinnaker guy, and the sheet is really easy to handle and rarely cleated. The spinnaker halyard will double as the retrieve line. A double patch system is normal, with a chute or hatch about a foot behind the stem to reduce tangles with the jib foot. The halyard and the retrieve should be arranged so that helm or crew can handle it. Launching and retrieving is quicker if one takes the halyard and the other the pole and sheet, but if its blowing 30 knots the helmsman will be a little preoccupied with keeping the black plastic pole with the translucent sheet above his head rather than below the water.

There's more than one way of dealing with the bowsprit of course, and there are some ingenious "one string" systems about. Much less hassle when they work properly, although you do end up with more halyard to pull up. The following is probably the simplest system to rig and set-up. The Tack of the kite is attached to a "guy" coming through the pole and to an anchor point in the boat. Its set up so that the line is taut and the spinnaker tack pulled right down to the pole end when the pole is pulled right out. A second line runs up to the bow and back to the end of the pole to pull the pole out. Depending on the friction in the system and the strength of the crew you might wish to have a 2/1 purchase on this. There's no retrieve for the spinnaker pole as such, the act of pulling the spinnaker back into the chute is enough to bring it back in.

If at all possible have a spinnaker pole strong enough to be unstayed. But if your spinnaker pole isn't strong enough to operate without a bobstay then the best way of arranging one is to have the "guy" running through the end of the spinnaker pole and out again and then down to the bow. In this case the line is tidied up by having it pass through a ring or pulley inside the pole, which in turn is pulled back with shock cord. This works well enough, but you'll probably need a little more purchase on the outhaul to make sure the bobstay is tight enough. You might get the occasional snaggle inside the pole too.The anchorage at the bottom of the bow is also a problem. Apart from the water resistance if its not made strong enough you can pull the bottom of the stem off.

Sail Shape Controls

Kicker and Cunningham are usually led back to mid length so that the helm can adjust them while sailing. You will need at least 6/1 Cunningham with a Mylar mainsail, and probably more.

One important tip with the cunningham - attach it to the boom. What I mean is that the fixed end of the purchase needs to be pulling up on the boom. This means that the ciunningham load offsets the kicker load and thus reduces the strain on the gooseneck fitting. Don't laugh - they break!

Kicking strap purchase should probably be 16/1 or 24/1, but it all depends on where the take-off on the boom is, and how low the other anchorage is. The boom take off should be a nylon strap. Proctor make very good and extremely expensive ones for the 14s, but any sailmaker will be able to oblige. A cascade type purchase is most common, but is quite draggy. DAve Roe uses an old fashioned differential winch, but with rope rather than wire, and this certainly makes for a much cleaner boat, although no-onme else does this.

The outhaul is normally cleated on the underside of the boom. You may not use it much when actually sailing, but you will need it when you see exactly what the wind is doing when you get out to the start. 6/1 is probably about right as you won't get a good pull at it.

Optionals.

The jib slot normally has a lateral control on a short length of track. About 3" of movement is all you will ever need, but if you don't know where that 3" is going to come you will want it longer. A lot of people have a height control, but it can be as simple as a cleat on the track, because you usually adjust it on the opposite tack. Don't clutter up the crew's area with a lot of string designed to let you adjust the slot in any direction at any time. He'll only trip over it and fall out on the last tack when you were about to win your first Cherub race.
Some people have a control to adjust the prodder. I don't bother because I want a rigid prodder to induce pre-bend. A length of track on mast or foredeck with a locking pin on the prodder slider is normally all you need. If you are inducing prebend make sure the prodder is strong in tension!
If you sail in some places you may feel the need of a main halyard. Wire is probably still best if you don't have a halyard lock. Be very cautious about Kevlar in this application because its notorious for breaking without warning. Spectra on the other hand seems prone to slippage or stretch due to the polyester sheath. With a 10/1 cunningham you can stretch just about anything, and of course the halyard also increases compression loads on the mast. A reliable halyard lock is great - again Proctor make a really good and expensive one for 14s. Personally I consider the loop of rope and hook approach to be far safer since you - or the rescue boat - can get the main off so much faster when capsized. Don't use kevlar for the loop though - it breaks. Use pre-stretch terylene - the length isn't enough for stretch to be a problem.
Whilst on the subject of main halyards I'll mention my favourite technique for landing on lee shores. Bring the boat hove to a little short of dead upwind of your destination. Pull both foils right out of the water (daggerboard rudders are great for this). Now you can just drift in sideways until the water is shallow enough, then immediately let the boat capsize, pick it up and carry it up the beach. (Don't try this at home with a Laser 5000 people). Even at inland clubs I find this easier than using a jetty.

Unnecessary.

A jib halyard is basically a device to put a 2/1 compression load down the mast. As no one uses a forestay you can't take the jib down while sailing, and rigging a boat on its side is so much more civilised. Have a wire strop and a T terminal, and use a short lashing to get the tension.
Adjustable standing rigging has never been used in Cherubs. Its heavy, expensive, and complicated.
Other gadgets also have no place..
Most of all, remember that the boat is weighed dry. Take all those ropes, weigh them, soak them in water and weigh them again. The difference will amaze you!
Finally, don't spend too much time worrying about gear. Instead go sailing! Provided all the gear works and is reliable then it is probably good enough. Being able to change the sail shape in the middle of the race is unlikely to make much difference to your final position, but capsizing at every gybe mark certainly will. There is absolutely nothing that improves boat speed as much as crew speed!
Gear & Fittings Installing a Bowsprit Building a Rudder GantryBuilding a Rudder Stock
In the old days making your own gear used to be a part of the game. Nowadays you can get most things ready made, but there is always scope for a bit of ingenuity to complete the job. This neat jib tack cover is from Dangerous Strawberry.

[Picture : Jim Champ]

Installing a Bowsprit.

The Pole.

Unstayed Carbon fibre poles are now more or less standard. Most are now home built, but a the lower section of a sailboard mast (7.4 or better stiffness) will also be good, as is the bottom section of a carbon dinghy mast. If you can get a broken one with the right bit left so much the better. The length of the pole is not restricted, but 1.8m from the stem is typical. Give the pole a nice rounded end, with a central hole for the string. A tapered pole is much to be preferred as it retracts much more easily.

Spinnaker Pole Mountings

New Boats.

Now that snouts are allowed getting the pole in becomes a lot easier. Because the pole is allowed to be 300mm from the end of the snout when retracted its possible to have the pole exactly on the centreline because it won't reach the front bulkhead when retracted. The snout will need to support the bowsprit in two places, and these will need to be very strong. The snout itself also needs to be very firmly attached - thoroughly integrated into the boat really! You'll probably be anchoring the job to the end of the snout too, so the loads will be pretty serious. The jib takeoff point will probably be right above the hole for the pole. This is not great engineering wise, because there will be a tendency to pull the hole oval - which, apart from the loss of rig tension, would also jam the pole! It would be as well to fabricate a carbon ring, about 2 inches long by about 5mm thick, and integrate the jib fitting into this. Its probably best to use a stainless steel D-ring or a shackle and bond it in place with generous quantities of uni-directional carbon The second point should be a small bulkhead about 300mm or so further - the stem position.. Have two rings with proper bearing surfaces. Probably the best is Tufset, from (Inter alia) RS Components as its a polyurethane that bonds well with epoxy. Nylon is also a very good bearing surface, but must be mechanically fastened as it won't glue in with epoxy. The whole assembly needs to be very thoroughly glassed in. The whole structure must be rigid, and you may have to reinforce the topsides, especially if its a wood boat. (You're not really building a new wood boat are you!).

Old Boats.

Life is a bit tougher for you. If you're doing major surgery and building a snout its just the same as above really. Otherwise the pole will be coming right back in the crew area, ideal for tripping up the crew every tack. Ideally the boat would have a tunnel besides the plate case for the pole - as we did on new boats in the days before snouts - but the chances of having a suitable tunnel on an unconverted boat are minimal. I don't know of any UK built boats which have one. Rather than coming through the bow on the centreline, a conversion will need the pole offset to one side, through the topsides just to starboard, so that it clears the mast. As far as the kite is concerned the existing stowage arrangements will do, but don't forget the longer luffed asymmetric will come further back in the boat. Arranging the pole is very much a matter of compromise. It wants to be as low as possible in the boat so the crew doesn't trip over it too much, but you will be limited by the height of the bow tank, not to mention the need to keep the end out of the water! If you have a full height bow tank then you will either have to rip the foredeck off and put a low tank in or else make a tube that extends right through the tank. If you do this the bowsprit will retract nearly back to the transom! The pole support arrangements will be much the same as on a new boat, but the bulkhead and anchorages will need to be looked at very carefully as loads are being put on that the structure was never designed for. Wood boats with 3mm topsides will have particular problems and will need extensive reinforcement.

Making the bits.

The tube that the pole slides through should be at least 4 layers of 200g glass (or better). Mould it round the pole. The technique used with mast building of coating the "mould" in wax and melting it out afterwards with hot water will be best, but failing that put on several separate layers of polythene sheet. It needs quite a few layers because the lay-up will shrink a little on curing. Unless you use wax you will have a lot of trouble getting the tube off the pole. Cooling the whole assembly down to shrink the tube helps.
I suppose foam sandwich is probably favourite for the bulkhead, even on wooden boats, because the width of the foam helps support and keeps everything stiffer. Glass it in well, and make sure its attached to something strong. If its just glassed onto topside and decking it will all warp.

Assembly.

This is definitely a job for measuring 3 times and gluing once. Start by fitting the bulkhead, but leave a bit of play where the tube comes through the topside. Check and double-check that everything is lined up correctly both with the pole in position and retracted. There is at least one boat where the kite tacks down 6 inches from the centreline - you don't want yours to be the second.
Gear & Fittings Installing a Bowsprit Building a Rudder Gantry Building a Rudder Stock

Building a Rudder Gantry

These are by no means essential. They help keep the back of the boat clear and aid steering on a two sail reach. On the other hand the loads are tremendous and a failure is a guaranteed race loser. A rudder gantry isn't that difficult an item to build, so here are a few pointers.

Materials

Successful gantries have been made out of:-
18mm diameter pultruded glass tube
Ordinary 1/2inch wood merchants dowel, reinforced with carbon or glass.
One inch balsa dowel core coated with carbon and glass
Aluminium tube
Titanium!
The trouble is that unsuccessful gantries have been made out of just about all these materials too.
The secret of a good gantry is the joining of all the components. The individual beams rarely fail, it's usually a join or the attachment to the boat. If you stick some bits of wood dowel together and bodge it with a bit of epoxy filler it's unlikely to stay together. Similarly if you attach a gantry - which creates considerable and variable tensile loads - straight to the outside skin of a foam sandwich transom the transom will delaminate and the outer skin will be pulled off.
Aluminium - let alone Titanium - fabrication is a rather specialised area, and best left to those with appropriate experience. Aluminium gantries assembled from pieces bolted together tend to fail, and an all welded construction is recommended. Without specialist facilities and experience you will be better off using composite construction.

The Bars

A typical gantry looks something like this. It consists of two V shaped assemblies top and bottom to take the loads, plus a further tube running diagonally upwards from the centre of the lower assembly to the transom to brace the structure further. Depending on exactly how your boat is engineered it may make more sense to have this brace running from the top downwards. Ready made pultruded tube has got to be the easiest material for the bars. Glass seems quite strong enough, but you can use carbon if you want to. If you feel like it and can reliably make good solid tubes then you could make some and use those for the structure, but purchasing the ready made stuff is not too expensive.

Assembly.

This is where the project will go right or wrong! I like to make up carbon brackets to join the components. I started by making up two V shaped assemblies for the top and bottom.
The join was made by making two triangular carbon/glass plates, about 3mm thick, and gluing them each side of the horizontal tubes with plenty of strong (with microfibres) filler. When this was cured I drilled and cut it for the next join. The vertical piece (that the pin slides through) was glued into the holes drilled in each bracket, and then the diagonal brace in the slot cut in its bracket. At this stage the joins look something like this.

Fill and smooth all the edges, fillet all the angles, and make all the corners nice and blunt. An angle grinder is quick and dangerous, a file slow and safe and essential in the trickier places. Now wrap every join with generous quantities of unidirectional carbon, and perhaps a layer of cloth over the top to keep all neat. Extend the carbon wrapping an appreciable way - maybe an inch - beyond the solid webs, and make sure that it tapers off neatly and smoothly to avoid "hard spots". The webbing of the joints with the plates, plus the tapered carbon wrapping, is what gives the construction its strength, so fiddle though it is, don't skimp this hassley job. The vertical tube can have nylon bushes top and bottom for the pin to save wear. If you have no other source buy RS400 ones!

Attaching to the boat.

Also vital. A solid stiff rudder and gantry assembly floating a few feet behind the boat has no effect on the steering! There is no substitute for having really stiff and solid mounting points built into the boat. Take the bars of the gantry right through the foam transom and glue them in with a nice strong filled mix. Cut them off flush with the inner edge, radiusing the corners. Cut some strips of unidirectional carbon about 4-6 inches long., "fray" one end, but leave the other end untouched. Wrap it into "sausages" and wet it out thoroughly with epoxy. You want to aim for enough strips that the sausages can only just be crammed into the end of the tube. Feed the good end into the bar for two or three inches, together with enough filler so that it is really thoroughly sticking to the inside of the tube. You'll need to use a small stick or something, but really get it in there. Now spread the "frayed" end, about another 3 inches, all over the adjacent inner skin, so that it fans out in every direction. In this way the loads from the gantry come right through the transom and are well spread out over the skin, avoiding the risk of delamination of the transom. On wood boats the bars should come right through the transom beams and be well epoxied and filleted in.

Fittings

A lot of problems with composite gantries and rudder stocks come when aluminium or stainless steel fittings are attached. It is virtually impossible to get a reliable bond between metal and composites. If you must use metal fittings then bolt them on solidly to ply pads - nothing else will do. Much better is to fabricate the fittings from epoxy/glass. A pintle will rotate just as happily in a glass tube as in a metal one, and you will find it a great deal easier to integrate the glass tube with the rest of the structure. No doubt it would be possible to create carbon pins for the male part of the fitting, but I prefer to have female fittings on both stock and gantry and run a single stainless steel pin right through the lot.
Gear & Fittings Installing a Bowsprit Building a Rudder Gantry Building a Rudder Stock

Photos (c) Jim Champ. They're of the gantry on my singlehander, not a Cherub, but its built like a Cherub!