Sunday, 31 January 2021

Restoration of 25ft Motor Cutter - 6

 Following on from the previous post where we made a small repair section for the forward end of the keel and cut scarfs to fit now we fit it into place....

With the section in place holes were drilled for the new bolts and 3/8" bronze threaded rod used to make them. The existing bolt holes through the fore deadwood and hog were re-used 

Bedding compound was made up in the traditional manner by mixing red-lead with linseed oil putty thinned with raw linseed oil.

The bolts were sealed by smearing them with bitumastic compound and a cotton grommet and everything was bolted-up tight.

Ingredients for making re-lead putty

Red-lead putty mixed and ready

New section of keel being offered-up

Bronze bolts sealed with bitumastic and cotton

Bolted up tight

There was a smaller section of timber right on the curve of the forefoot that was crumbling from being encased in the iron 'shoe'. This again was a later addition and presumably a repair after past damage.

With the old bit of timber chipped away the remains of the fixing screws were extracted and the remaining timber cleaned-up. A new piece was cut from the remaining oak and once a snug fit was achieved the mating surfaces were primed with sealing epoxy.
Forefoot having a clean-up for a new piece of timber to be fitted

At this stage in our works the weather got colder and wetter and the virus pandemic halted our works.

I have continued with some small jobs such as priming and varnishing bare wood inside the boat and doing some jobs on the engine.
Varnishing - 3-coats for now to seal and protect the new timber

The Dorman engine is missing its dynamo and instead the drive shaft - which is an extension of the governor shaft - had been fitted with a 'V' belt pulley but no clue as to what it drove. Looking at the engine's drawings it appears that this shaft runs in plain bearings that are splash-lubricated inside the gearcase; hence this shaft is not really suitable for a radial load that a 'V' belt drive would apply. Originally a C.A.V. dynamo was coupled to this shaft and directly driven.
I have been hunting for the 'correct' D45R dynamo for a while without success but then realised that the '45' means a 4 1/2" body diameter and instead a Lucas type C45 dynamo would fit and would have a low enough 'cutting-in' speed. To check this before splashing out on a suitable machine I made a cardboard mock-up to check for fit on the engine - which it does.

Cardboard mock-up Lucas C45 dynamo to check for fit. The oil pressure gauge is temporary.

Now I have obtained an enclosed (i.e. non-ventilated) C45 dynamo with a 1955 date that was probably from a tractor. To fit it to the engine I have to make some clamping straps and a coupling hub as the drive is basically a short piece of 1 3/4" rubber hose secured by hose clips. The drive hub is on order as it has to be made specially and I've no access to a metalwork lathe.

This pulley had been fitted to the drive hub

Pulley removed to leave the 1 3/4" spigot - this turns at 1.4 times engine speed

The engine is also missing its 'dashboard'/control panel on which controls and instruments are mounted. I have a tachometer and have obtained throttle control lever, oil pressure gauge, ammeter and various buttons and switches and the current job is the manufacture of the mounting board, roughly copying the illustrations and drawings in the engine manual. I have made a frame from 1" angle to support a panel and this is as far as I've got now.

This is what it should look like

Control panel manufacture underway

Just before Christmas 2020 a timber supplier I occasionally order from was offering 1m3 bundles of sapele offcuts. I purchased one and a whole stack turned up so now we've got sufficient timber for pretty much all the internal joinery and also the framing for the cuddy and cabin top.

Plenty of sapele - most of these are more than 4m long.

Wednesday, 28 October 2020

Restoration of 25ft Motor Cutter - 5

 Work to repair the keel involved cutting a new scarf on the forward end of the keel which had been lopped off by the original repairers. We had previously driven out and removed the four 5/8" copper rivets that held the forward lifting eye plate but there remained a 3/8" copper keelbolt through the section in which we were to cut the scarf.  There is a bolt like this every 6-7" throughout the length of the keel.

Keel bolt being driven out. Line of scarf marked on keel timber.

The scarf line was marked on the keel and using a power reciprocating saw (which was a Godsend as the timber is very, very hard) the scarf was cut to near the line.

Sawing along the line of the scarf

We attempted to rasp, chisel or plane the scarf but lying on one's back under the boat coupled with the hardness of the wood made this a very difficult task. We opted for the router solution and carefully made and clamped a guide ramp to the keel and ran the router fitted with an end mill over it.

Router guide clamped to keel

Cleaning up the face of the scarf didn't take long

The scarf was given a final clean up with the chisel.

Completed scarf. The holes are the lifting eye-plate bolts

The shape of the keel repair piece was marked onto our new length of timber and it was sawn and planed on the bench till a good close fit was obtained. This took time.

Cutting and fitting the new timber section

Checking the new section for closeness of fit.

The forward scarf had an existing stopwater tight in the joint between forefoot and hog underside and the new timber's scarf was cut to match this. The sides were carefully planed to give a seam for caulking and it was made to fit snugly up to the underside of the hog.

Next job will be to drill new keelbolt holes and bed this in and fasten. I've got some bronze rod, nuts and washers on order - eye-wateringly expensive!

Tuesday, 6 October 2020

Motor Cutter Restoration - 4 Work continues

 Work on the boat slowed somewhat during the lockdown as I was only able to visit the boat occasionally on my way home from work. My buddy, Pete, was unable to work with me. However I was able to clean down her bottom and get some primer on to slow her opening up as the weather became warm and dry in April.

Underwater primer going on

A couple of coats of primer on the bottom

Another job I tackled was to find a coupling to fit the propeller shaft that would match the output flange of the Dorman's gearbox. Nothing was available off the shelf so I drew a dimensioned diagram of the coupling to suit the 12:1 shaft taper and keyway and had it made by a specialist. Not cheap but it is an excellent job. The Cutter has 1 1/8" diameter tail shaft which is a non-standard size these days and I was warned that if a new shaft was required it would have to be specially ground. Fortunately the shafting is in good condition with very little wear, straight and no damage.

Custom-made prop shaft coupling

Perfect fit on gearbox...

...and shaft taper.

Various small holes in the hull were plugged and repaired..

This was were the engine intake seacock had been moved to.
All these holes were plugged and a tingle glued on the inboard side.

Nasty holes and damage caused by a sacrificial anode mounting studs

Holes cleaned out and iroko plugs glued in place - grain orientated in line with plank's.

Fortunately the boat's original seacock had survived and it was carefully dismantled and cleaned. Its original location and part of a bronze adaptor plate still existed, although plugged and covered with a wooden tingle.  This was removed and the fastening holes opened up again since I'm going to re-install the seacock in its original location as per the plans, since it will be adjacent to the engine's pump intake.

Seacock checked and cleaned - a lovely bronze fitting.

Original seacock location

Part of one of the mounting plates; holes line up exactly.

Some small repairs were done to the engine beds; removal of studs from a former engine installation and filling of holes. Loose paint was stripped from the area around where the engine sits and also in the stern sheets under the thwarts. Primer was applied followed by bilge paint and white undercoat.
Bilges under engine cleaned and primed

Loose paint - lots of it - stripped in stern sheets

... and primer applied.

Repaired frames primed

Bilges given a coat of grey bilge paint. Orange glow caused by sunlight shining through the cover.

The midships bulkhead was sealed and fastened into place and the thwart screwed down tight on top. The knees were then nailed and riveted - these used 6-gauge copper nails up to 6" long with 3/4" roves to suit.
Bulkhead finally fitted and fastened

Knees being fastened

Midships and forward thwarts fastened

These stiffen the boat up considerably

We were itching to have a 'play' with the engine - one of two that I have. The first is complete but the second has been partially dismantled - goodness knows why!?
It was over a year since the engine last ran so we removed the rocker cover, checked the tappet clearance and poured plenty of oil over the valve gear and cranked the engine over by hand. A fuel supply was rigged up, battery and starter button connected and after some bleeding of pump and injector lines she started and ran..
Checking valve gear

Fuel and cooling water hooked-up

It lives!!
I have made some threaded adapters that have allowed me to install some more modern glow-plugs to aid starting. The originals were low voltage series-connected but I've fitted some from a Land Rover diesel that work really well.

There are a few jobs to do to the engine before it can be installed: It needs a dynamo or alternator to be driven from the 'Vee' pulley on the side of the engine, speed control and linkage and a control panel to mount gauges and switches.
In the meantime we cleaned the engine, primed it with red-oxide and enamelled it in a more appropriate grey that may approximate the colour it originally wore in service.

Cleaned and de-greased

Red oxide on

Two coats of grey enamel...

..and black fitments.

There are lots of parts on the Dorman that can be polished.

Back to the Cutter we investigated the suspicious steel 'shoe' that encased the forward part of her keel. It was bursting with rust and so the remains of bolts were cut off and driven out and the thing was sliced and prised-off.
Underneath was a tidy piece of oak that had been slotted-in forward of the lifting plate and scarfed to match the original stem piece. The after scarf was too short and was obviously weak so we drove out the four heavy copper rivets holding the lifting plate to enable a long scarf to be cut. 
Cutting away at the steel 'shoe'.

Peeling it away

Freeing the forward keel section

Cutting the lifting plate fastenings

..and driving them out.