Topic: McLachlan Class Lifeboat (Read 11543 times)

gribeauval · « **on:** December 31, 2012, 06:19:57 pm »

Over the holiday period I have been banned from any building work on the big boats I have on the slips.
HOWEVER I can't be banned from playing with my Christmas presents !! These are nealy all drawings of lifeboats from the RNLI that I didn't already possess and amongst them was two drawings of the 18ft 6in McLachlan Class Lifeboat, a small boat used as an inshore rescue craft prior to the introduction of the Atlantic 21 class. Very few were built and when the Atlantics went into service some became boarding boats for large ALB's (Aruns etc)which were kept afloat. One of the class has been preseved in the National Collection of Lifeboats at Chatham Historic Dockyard.

So I scanned the drawings, which are 1/8th scale, and reprinted them at 1/12th scale. As the boats had twin inboard/outboard drives and no way of making scale ones to fit ( commercial ones are too expensive and too big!!) I decided that the answer was to emulate the old Lesro Atlantic 21 kit and fit a single prop on the centreline and use the outdrives as rudders. This means that when on the water it looks OK and doesn't look too bad out of the water. A check of space available below the cockpit floor showed that a Speed 400 and a 30mm prop could easily be fitted.

A ply keel was cut and the propshaft inserted and glued in place.

As the drawing does not contain a set of lines the frames were made using the sections given, with a little 'lofting' where needed, to produce an acceptable shape.

gribeauval · « **Reply #1 on:** December 31, 2012, 06:32:36 pm »

The inner cockpit walls and the deck edge stringer have been fitted to give the hull stability and prevent it from warping. A start has also been made on the angled rear and side decking.

The rest of the side and fore deck have been completed.

The hull planking has been commenced using 3/32" balsa, this will produce a lightweight hull and the oversize thickness will allow any lumps to be easily sanded out.

The large cockpit drains have been made and fitted so that the planking can be completed around them.

gribeauval · « **Reply #2 on:** December 31, 2012, 06:37:43 pm »

The planking has been completed and the bow section filled with balsa block. The whole hull has been sanded to shape and is now ready for a little filler where needed and then a layer of finishing grp tissue will be applied.

Next thing will be to add the multiple spray chines to the hull.

Rottweiler · « **Reply #3 on:** December 31, 2012, 06:49:20 pm »

Wow, thats quick progress Mike,its looking good already.I like the idea of using a single prop instead of the jet/Z drives.
Mick F

gribeauval · « **Reply #4 on:** January 03, 2013, 07:09:26 pm »

The multi spray rails have been fitted onto the hull. To obtain the correct triangular hull section 1/16th" square obeche is glued onto the hull in the correct positions (8 each side).

When they are all in place the spaces between each one is filled with filler and allowed to dry. The filler is then sanded to shape until the obeche is exposed at the lower edge and the hull is just exposed under the upper strip of timber.

This now gives the hull its stepped appearance often known as a 'ragged chine hull'.

Rottweiler · « **Reply #5 on:** January 03, 2013, 07:25:16 pm »

Mike,one of your latest photos does not appear on my 'puter? The hull really does look like it should,thats a clever way of getting the correct shape.Cant wait for the next instalment!
Mick F

gribeauval · « **Reply #6 on:** January 03, 2013, 07:35:02 pm »

Quote from: rottweiler on January 03, 2013, 07:25:16 pm

Mike,one of your latest photos does not appear on my 'puter? The hull really does look like it should,thats a clever way of getting the correct shape.Cant wait for the next instalment!
Mick F

They all appear on mine Mick, try hitting refresh.

Mike

Rottweiler · « **Reply #7 on:** January 03, 2013, 07:47:20 pm »

yep that worked! thanks!

gribeauval · « **Reply #8 on:** January 06, 2013, 03:29:27 pm »

Next problem to be addressed is the question of steering. The original boat used steerable outdrives but as this model is single central prop driven then the twin outdrives can be used as rudders.

Profiles have been cut from two layers of styrene laminated with a section of hinge between them and a control horn added.

After priming and painting satin black they are test fitted onto the stern where the other part of the hinge is fitted and connected to the steering servo. The hull has also had the first of three coats of spray primer.

Rottweiler · « **Reply #9 on:** January 06, 2013, 04:28:30 pm »

Very very clever.Well thought out Mike.She is coming along nicely.
Mick F

triumphjon · « **Reply #10 on:** January 07, 2013, 12:44:47 pm »

looks good , id be interested in obtaining a set of your working 1/12th scale drawings please ?

gribeauval · « **Reply #11 on:** January 07, 2013, 01:01:11 pm »

Quote from: triumphjon on January 07, 2013, 12:44:47 pm

looks good , id be interested in obtaining a set of your working 1/12th scale drawings please ?

Drop an email to the Engineering Secretary at RNLI HQ in Poole and they can supply the two drawings @ 1/8th scale very cheaply, ( they need all the cash and support they can get to continue their good work!!) then a quick trip to the print shop and have them re printed at 67% of full size to give you 1/12th scale drawings.

mailto:louise_chapman@rnli.org.uk

Mike

gribeauval · « **Reply #12 on:** January 07, 2013, 01:59:34 pm »

Whilst sanding down the filler/primer coats I had a niggling feeling that something was wrong with the chines I had fitted. A check through the photos I have of the boat showed that the chines at the bow do not sweep up at a constant spacing but are spaced closer together at the stem thus the work I had done was wrong !!!
The offending forward third of the chines (No's 4,5,6,7,8) were marked up for removal

The section has been removed with a combination of scalpel, very sharp small chisel and scraper back to the grp layer of the hull.

New stringer sections have been glued onto the hull with the correct spacing giving the sweep of the chines the correct flow from stern to stem.

Filler has been re-applied and when dry will be sanded to shape to match the rest of the hull.

Moral of the tale is never assume........ CHECK !!!!

Rottweiler · « **Reply #13 on:** January 07, 2013, 03:11:09 pm »

I suppose you could say better you found out now rather than later! I am sure it will turn out right in the end! Keep up the good work Mike.

triumphjon · « **Reply #14 on:** January 07, 2013, 04:49:08 pm »

thanks for the email link , i will get to build one eventually , much easier these days with the better quality motors and more compact radio equipment weve got available to us ! your example looks really good . jon

gribeauval · « **Reply #15 on:** January 10, 2013, 01:49:24 pm »

After two coats of spray filler, two coats of primer and two coats of orange the hull is ready for details to be added.

Whilst waiting for the paint coats to dry the removable deck has been made to the correct camber and the control console fabricated. This has also had primer and will be painted sky blue (see first post in this thread) !!

I 'borrowed' a couple of crew from other lifeboats to give some idea of the small size of this class of Lifeboat.

gribeauval · « **Reply #16 on:** January 15, 2013, 12:03:57 pm »

The hull has now had the forward spray deflector bent and fixed into place then the whole of the interior painted in the light blue of the original boat. The boot topping was carefully, and with great frustration, masked off over the multi spray rails and painted black and the rubber rubbing strip at deck level added.

The rear engine cover has been made and fitted along with the anti-slip areas on the deck.

Smaller details next.

Neil · « **Reply #17 on:** January 15, 2013, 12:53:02 pm »

Looking superb Mike.

neil.

gribeauval · « **Reply #18 on:** January 15, 2013, 01:06:55 pm »

Quote from: Neil on January 15, 2013, 12:53:02 pm

Looking superb Mike.

neil.

Cheers Neil! Still it's a bit of an ugly looking lifeboat, not very much elegance of line.

Mike

Neil · « **Reply #19 on:** January 15, 2013, 01:34:07 pm »

People say that of the Tamar, and in the past the Solent..............but I wouldn't care how she looked if she were coming over the horizon as I took my last gasp..........

there's no ugly lifeboat, in my mind matey.....and she's a totally different little boat..........as my daughter said last night when she saw it before paint........"AHH! isn't it cute......."

neil.

Rottweiler · « **Reply #20 on:** January 15, 2013, 01:39:37 pm »

got to agree there,she looks better and better.A superb replica Mike.
Mick F

gribeauval · « **Reply #21 on:** January 28, 2013, 03:40:29 pm »

More of the details have been added to the McLachlan, rails, scuppers, nav lights, cleats, radio antenna and the boat number done on the hull. In this case A-505, the Humber Lifeboat boarding boat based at Spurn Point and used to get the crew from the shore to the afloat ALB moored in the estuary.

All the control gear has been refitted and she is ready for the water.

Now that all the snow has gone and the ice on the test tank melted it's 'sea trials' time! First indications show that the use of the outdrives as rudders works very well and the single 30mm prop gives good scale performance with the Speed 400 motor.

Click on the picture below to see the boat in action.

sailorboy61 · « **Reply #22 on:** January 28, 2013, 03:51:17 pm »

Simple but elegant, and great show of building skills.

Rottweiler · « **Reply #23 on:** January 28, 2013, 04:22:09 pm »

what else can I add?A really lovely looking model Mike.Well done.
Mick F

Martin (Admin) · « **Reply #24 on:** January 28, 2013, 05:15:36 pm »

Quote from: sailorboy61 on January 28, 2013, 03:51:17 pm

Simple but elegant, and great show of building skills.

Well put!

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Author Topic: McLachlan Class Lifeboat (Read 11543 times)