Centre Plates & Winches on Finesse Craft.
Early models of the Finesse 21 had a rectangular plate that sat in a slot within the keel assembly and a low box within the cabin.
On later boats (the change of date being unknown) an ‘L’ shaped plate was fitted – its shape being like that of the F24. The aft end of this centre plate comes up into a centre plate box arranged at the aft end of main cabin.
It should be noted however, that some boats of a later vintage, such as the gunter rigged Cumulus (N0. 51) and gaffer, Ivy May (No.63), both had a rectangular plate too, set in a long low box.
It should be noted that even when a rectangular plate was fitted to a later F21, the pivot bolt was sited in the ballast keel and not through centre plate casing. Note location of pivot hole in plate the repaired plate pictured.
The centre plates on all models is manufactured from 13 mm mild steel plate, hot dipped galvanised.
Pivot bolt and lifting wire bond:
On early models the centre plate bolt is accessed inside the main cabin. On the later models, the pivot bolt was moved to the outside and set in the ballast keel.
The size of bolts used may well differ due to owner changes, so it would be wise to make a note when replacing and file the information.
The lifting wire is attached to the upper edge, aft, with a pin riveted between two lugs.
Note the wasted and broken lugs on the centre plate removed from Woodmouse by her then owner some years ago. It was renewed!
During the ownership of a vessel, owners will develop a routine for inspection of this area. I would suggest when the lifting wire is inspected the same should take place with the centre plate itself.
The turning sheaves for all classes of boats need to be inspected from time to time. F21 Drifter has been fitted with an adapted pulley block mounted within a stainless steel support. Drifter’s owner has found this to be effective.
It should be noted that a larger sheave diameter lessens the working and ultimately the hardening and breaking of the wire’s strands.
A variety of winches are likely to be found as time has progressed, however, many vessels still sport their original winch.
A common winch was one produced by Southend Engineering of Leigh-on-Sea, Essex (now defunct). It had a dog clutch with a handle to release/lock the winch and a winding handle with a length that transmits a significant turning force.
The dog clutch is like that of the ‘standard’ F24 winch. A series of plates shows one of these opened out for maintenance.
Points of interest:
Currently we know the whereabouts of several F21s up to No. 11, then we have a gap to No. 27, then on to No. 34. There is some constructional history missing which needs to be filled! No. 27 was severely damaged in a yard fire and owner of No. 34 has not responded to overtures.
There is an inconsistency of centre board designs fitted to F21s. Ivy May, No. 63, is a later built Mk 2 with the stepped coach roof running forward over the fore cabin, yet she was built with a long low box with a rectangular centre plate. No. 51, Cumulus, also has a long box with rectangular plate, but this boat does not have the ‘improved’ cabin structure.
It has become clear that following the change to an ‘L’ shaped plate on the F21, it became a choice for a particular boat’s first owner. This, to an extent was the same for coach roof design.
The F24 has had a standard plate design since the inception of the boat. It is ‘L’ shaped in configuration and fits into the keel and rises into a box constructed at aft end of slot at aft end of main cabin.
The F24 centre plate is manufactured from 13 mm mild steel plate, hot dipped galvanised on completion.
Note: the top of the slot section of keel is covered by a sealing board which can be seen in plate 5. This is in effect a hull plank. On Whimbrel it is bedded on a liberal coat of bitumastic paint.
Following are a couple of plates showing a new centre plate awaiting fitting and then in situ.
The owner of F24 Gypsy modified his plate when renewing c2015. The area round the pivot hole had pads of around 6 mm welded each side, thus essentially doubling thickness. This was to increase amount of plate metal around pivot bolt.
On a visit to Faversham I photographed the removed centre plate from F24, Quo Vadis, in Alan Staley’s yard at Chambers Wharf. The plate thickness has been increased over a wide area around the pivot bolt.
Centre Plate Pivot Bolt & Lifting Wire:
In many respects, much of what is written here will be largely like what F21 owners will need to do.
The F24 centre plate bolt is located outside. It is just aft of the forward end of the plate slot. The hole is about 150 mm above bottom of ballast keel. The recess can be seen to lhs of plate 12.
When I first used metric bolts, I had to drill through the bolt hole – easily done with a large electric drill. It is doubtful if anyone will find an imperial dimensioned bolt now in use.
Leave the slot area clear when you chock up. The slot runs back to just about on the line of the aft cabin bulkhead. Ideally chocks need to be around 400 mm in height for ease of access for bottom work.
The pivot bolts are likely to have deviated from original build and an owner would be advised to make a note of what is fitted. On Whimbrel, I use a M20 x 190 mm galvanised/anodised bolt.
An F24 friend tells me that his boat had a M16 stainless bolt fitted when he purchased the vessel, but he changed to a galvanised mild steel bolt: the stainless steel was causing corrosion of pivot hole in the plate. Beware: stainless steel is not the ‘be all and end all’ in salt water.
Originally the bolts were cemented in. On Whimbrel, for several decades, I have used a filler of waterproof mastic squidged over.
Make a note on which side the nut is fitted This is especially important if laying boat over on a hard to do a bolt renewal when antifouling, for instance. (The method most often used by author).
To change bolt on yacht club hard: expose nut side of bolt first. Careen boat over as tide falls to a level halfway down bilge stub. Push hard on deck edge (takes some effort to get going for boat will happily sit on ballast keel) and then let her over gently. If you are too early, the buoyancy aft will lift her again.
Note: if you do want to sit upright, you can, but chock the bilge stubs. I have a set of legs I screw to outer face of stub.
With boat heeled, accessibility to pivot bolt is easy. Remove whatever covering has been used. Remove nut to last two threads, screw in new bolt (greased) and begin to tap through – club hammer often needed. Taking weight off the pivot bolt by temporary chock on underside of plate edge helps.
Once bolt has moved, remove new and old nut, and tap new through knocking old bolt out.
Part fill annulus with grease, covering bolt head, clean edges and ballast keel face and cap over with water resistant sealant – bathroom type works well. This capping can be seen in plate 10, on the ballast keel.
I have found it increasingly difficult to obtain the ‘ordinary’ 4.6/4.8 grade mild steel hot dipped galvanised bolt. They are made in China and in the USA, but UK suppliers/manufacturers appear to have little to do with them, concentrating on 8.8 grades and above (higher carbon content) high tensile steel bolts commonly used in the construction industry.
On Whimbrel, I have been renewing on a two-year change cycle, but have returned to renewing each year, due to finding the 8.8 grade wasting excessively. They are cheap at circa £50 for a box of ten, from builders/fastening merchants, so does it matter… A fellow owner, locally, also renews annually, stating around 30% wasting.
I should add that Whimbrel is in use often – more than 100 days/year – so plate is being used frequently.
Lifting Wire & Bond:
For the past 37 years I have renewed the lifting wire and pin at around five to six-year cycles. The pin by this time is generally 50% wasted.
If the wire begins to breakdown with a few broken strands, it is time to renew at next annual refit.
Make sure the maker of your new wire fits a ‘long’ cringle otherwise the swage could catch the top of the lugs on centre plate, preventing swivelling. The lifting wire should be of the ‘rope laid’ type and not 1×19 rigging wire which can crease easily and will work-harden far more quickly. If the wire begins to break down with a few broken strands, it is time to renew at the next annual refit.
For Whimbrel, I always have a spare pin in the ‘boat box’ prepared at one end ready to insert, cut and rivet over. I use a length of plain galvanised mild steel bolt. When fitting, cut around 3 mm longer than width across plate lifting lugs, enough to enable riveting.
When removing old wire, tie a piece of light burgee halyard line to old wire to enable pulling new wire back up!
To remove pin, it needs to be cut through and the ends forced out – old screwdriver and hammer needed.
To rivet new pin: with a second person holding a club hammer against pin on rivetted side, use an engineer’s hammer (ball pane) and gradually rivet over cut end, working round in a planishing action.
I have found that natural rusting will seize pin in place – which others have found and reported.
In plate 24, note the turning block that feeds wire to from top of centre plate box and a sister turning sheave within the main upper timber of the centre plate box.
Some years ago, on Whimbrel, I made a new set of bronze sheaves of an increased diameter – by around 50%. Larger ones would be preferable but lifting wires have lasted longer.
Note too, in plate 25, the small brass plate let into side of centre plate box upper timber. There is a sister the other side. I fitted a pin running right through upper timber when renewing a larger diameter sheave.
With the decorative cover removed and with wire completely slackened off, the sheave can be carefully removed whilst afloat(!). This sheave is liberally coated with waterproof grease from time to time.
Centre Plate Winch & Operation – in general.
All classes of boats now seem to have a variety of winches. These notes relate to the Viking winch manufactured by Southend Engineering of Leigh-on-Sea, Essex (Now long defunct). This unit was commonly fitted from early/mid 1970s on F24s. The Viking winch found on F21s is similar.
The small handle disengages/engages a dog clutch. The large handle is used to raise/lower the centre plate.
Winding directions may differ depending on individual boat set ups.
Winch operation – all boats – especially for new owners:
I have been whacked across the back of a hand twice by the winch handle. It hurts … my shipmate will agree, she has done it too…
Take a firm grip on the winch operating handle before disengaging the clutch handle.
Release clutch by unscrewing.
You will feel weight of plate on operating handle. Wind plate in/out as desired.
Re-engage the dog clutch – do not overly tighten this.
Note: If the wire slackens and the plate stays put, then the slot has become clogged with either mud or a stone(s). If you have left a little slack in wire, then by lifting and lowering, the obstruction can be forced out.
If not: you will need to knock top of plate with a punch and club hammer.
First: remove the top decorative cover that hides the lifting wire and sheave in casing top. (If your case top has not been ‘adapted’ to allow use of a punch rod, then the top of the box will require to be removed from the centre plate case too).
The punch needs to fit immediately forward of the lifting wire sheave in the case top.
With the punch located on top of plate and not the wire (it can be felt), hammer hard to try and shift the plate.
If this does not work, it is likely you will need to have boat lifted out!
Or, put the boat on a concrete hard and careen her as previously described.
With boat careened over on hard, run a bent tool (old file/saw blade) along slot either side of plate and try to clear stones/mud/obstruction.
NOTE: On a drying berth, I have ALWAYS left Whimbrel’s plate slacked off about 1/2 to 3/4 turn – it allows the plate to ‘float’ as boat settles/lifts. It has never stuck.
The boat is also used regularly. If you are not out regularly, do at least raise lower the plate to ensure clear of mud if on a drying berth.
Viking Winch Maintenance:
This type of winch is easily dismantled. This should be carried out about every other year to clean and lubricate with fresh grease.
Either lower right down when afloat to take all tension off the wire or onto ground if out on a hard or on a mud berth.
Remove the grub screw (Allen) in end nut, then the nut itself.
The winch drum can then be slid off. Beware of the spring cups.
Inside, there are a number of spring-loaded bronze cups that bear on a bronze plate. The spring pressure is what disengages the dog clutch.
Clean all parts and re-grease. The same waterproof grease used for shaft stuffing box is good.
When reassembling, the grease keeps all in place.
When the parts are cleaned, check for wear. This is not always obvious, however, if when disengaging the dog clutch, the winch is catching when operated, this means the cups and or the bronze bearing surface have worn. It is often the cups at fault.
Over the years, for Whimbrel, I have made two sets of cups, from bronze rod.
Finesse 24 Centre Plate Drawings:
These two drawings differ slightly, so beware. Probably best to get old plate copied, using drawings to give good clues to any finalised shape.
The detail of lifting wire bond lugs on the ‘Whimbrel’ drawing is as per build design. Note: I have increased the diameter of my bond pin to 12 mm.
A note about use of centre plate, F24 biased:
You need to use some of the plate to sail the boat properly. In general, with standard jib set, on Whimbrel I have come to use about 4 to 5 turns down. With genoa set (i.e. full roller set foresail) 6 to 7 turns has been found to be good.
On a broad reach, little or none is needed. Downwind I always wind up fully.
Each owner will have their foibles here, but I suspect have found much the same.
Removal of a Centre Plate.
F21 & F24:
The boat requires to be lifted to a similar height that is needed to carry out the renewal of lifting wire bond.
Prepare the ground – an old sheet of plywood is good to lower plate onto and ‘drag’ clear from underside.
Drop centre plate to ground at aft end. Release wire from winch drum and drop out with a retrieval pendant.
Undo the pivot bolt. With the plate supported by a chock and another person, remove pivot bolt.
The centre plate can then be eased out and down to ground. The weight is easily dealt with by two persons for either F21 or F24.
F21 with rectangular shaped centre plate:
Method passed by Finesse 21 owner, Graham Hadaway.
With the rectangular shaped plate, it is possible to withdraw it into the cabin through the top of the case.
Remove centre plate box top cover and manoeuvre a thin line to go round the plate at the forward end and secure.
Remove pivot bolt. Clearly this cannot be carried out afloat!
Once it is part clear, it can be manhandled by using a couple of ‘G’ clamps on the plate as handles. Hope that makes sense.
Only one Finesse 27 was known to have been built with a centre plate. This was fitted into a slot in her ballast keel. This boat, Bonito, had a probable sail number of 102. Sadly, this boat was broken up during 2019.
The other known Finesse 27, Tugela, sail number 101, was not fitted with a centre plate.
As far as is known, none of the Finesse 28’s built were fitted with a centre plate, it being deemed unnecessary.
The F28 was redrawn by Maurice Griffiths as a development of the ‘27’ and has a look more reminiscent of the two Lone Gull designs built for himself.
Brief Historical Information
For historical purposes, the Finesse 27 was stretched up from the Finesse 24 which evolved from stretching out the successful F21’s design.
The first F24 was designed by Alan Platt in accordance with the wishes of and discussions with the first owner of White Dove (Delphinus as built) in 1969.
It should be noted that ONLY the original hull of the smaller F21 craft was designed by Laurie Harbottell. It was based on a boat he built for himself. This boat, Lady Beatrice, is still sailing and based at Leigh-on-Sea, Essex.
Compiled by Nick Ardley.