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Sprite Plus
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About this boat
This Sprite Plus is a lengthened version of the LesRo Sprite that is now 30” long to make it a better boat for use in all weathers, 12 months of the year.
The plans for this lengthened model were drawn up by Chris, who is also planning to build one for himself to use it with an outboard motor - something that looks really good and should be a superb combination.
Meanwhile I am building this as the “prototype” Sprite Plus with a conventional single shaft drive, and I will keep Chris aware of any changes that I make that may be of benefit to him when he builds his own version at a later date.
The main design change (apart from the length) is the front cabin detail that has changed from a flat screen to a “V” shaped double windscreen design.
Chris had drawn this on the plan, but (as is the way with prototypes) I have changed it a little as things tend to “evolve” with prototype builds and my version has been planned to be built right from the start with an integrated cabin construction with access being gained via a “lift-off” cabin top.
Chris prefers to have a complete lift-off superstructure that does give better accessibility, but I prefer to forgo a little accessibility and gain the superior strength and water-proofing that the integrated construction type provides.
My build choice has been ingrained in me ever since I raced my Aerokits Swordsman in an off-shore race in the open sea in the late 1960’s and my friend who had a very similar Swordsman (but with a lift-off cabin) was unable to complete as his complete superstructure was easily “washed-off” by any wave or heavy wake, and even when it was able to stay in place, any “deck-wash” tended to enter the hull as it crept in under where the superstructure sat on the deck.
My friend was a superb craftsman who earned his living as a furniture maker, and so his build quality was far better than anything that I was able to achieve (then or now!), but the construction method could never be as water tight - even with his perfect fit between deck and superstructure.
My build is not yet complete, so I will change the “lead picture” when it is finished, but for now the picture shows the design as it is being built.
Bob,
The plans for this lengthened model were drawn up by Chris, who is also planning to build one for himself to use it with an outboard motor - something that looks really good and should be a superb combination.
Meanwhile I am building this as the “prototype” Sprite Plus with a conventional single shaft drive, and I will keep Chris aware of any changes that I make that may be of benefit to him when he builds his own version at a later date.
The main design change (apart from the length) is the front cabin detail that has changed from a flat screen to a “V” shaped double windscreen design.
Chris had drawn this on the plan, but (as is the way with prototypes) I have changed it a little as things tend to “evolve” with prototype builds and my version has been planned to be built right from the start with an integrated cabin construction with access being gained via a “lift-off” cabin top.
Chris prefers to have a complete lift-off superstructure that does give better accessibility, but I prefer to forgo a little accessibility and gain the superior strength and water-proofing that the integrated construction type provides.
My build choice has been ingrained in me ever since I raced my Aerokits Swordsman in an off-shore race in the open sea in the late 1960’s and my friend who had a very similar Swordsman (but with a lift-off cabin) was unable to complete as his complete superstructure was easily “washed-off” by any wave or heavy wake, and even when it was able to stay in place, any “deck-wash” tended to enter the hull as it crept in under where the superstructure sat on the deck.
My friend was a superb craftsman who earned his living as a furniture maker, and so his build quality was far better than anything that I was able to achieve (then or now!), but the construction method could never be as water tight - even with his perfect fit between deck and superstructure.
My build is not yet complete, so I will change the “lead picture” when it is finished, but for now the picture shows the design as it is being built.
Bob,
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We popped down to The Fisherman - a really nice pub close to our local club lake that serves up some good food, and an ideal place to have some lunch on my 77th birthday.
Not wanting to miss an opportunity to drive a power boat, I popped my orange Avanti into the car…..just in case……
After our lunch, we walked over to the lake and grabbed the Avanti .
This particular ARTR Model from Thunder Tigre is sadly no longer available, and there are NO SPARE PARTS available for it anywhere world-wide!
This may be the reason why this super little boat has only had one previous drive, but I realise that there is no point in keeping it and not using it, so I now intend using it as often as possible - starting today!
As soon as the AVANTI hit the water I remember why I like it so much - after all, it is only another plastic RTR model boat, but this one runs so smoothly and is really very nice and QUIET - not at all like most of the other small fast plastic boats we occasionally suffer on our club waters!
Sadly, my spontaneous action of bunging it in the car did not allow for any preparation (!) and proved that LiPo batteries do not indefinitely hold their charge !
In addition, the lake was unusually full of floating weed that almost immediately stopped the rudder working, and then the prop, and then the rudder again !
After clearing the weed yet again (4th time) the boat set off - and died - right in the middle of.the lake!
Fortunately, Andy was there with his two impressive amphibious craft and rescued my “dead” boat by gently pushing it back to shore.
This got me thinking that maybe I should start thinking about building that PUSHER FRAME that I originally thought about including when the idea of a 30” flat nosed “punt” type of boat became the Sprite Plus.
This would not have helped me today, but this was the first time that I had ever only taken ONE power boat with me, and the ONLY time EVER that I have not prepared a boat and fully charged its batteries before leaving home with it.
Lesson learnt…..and as soon as I have water-tested the Sprite Plus , I will take another look at designing a pusher-frame that can be bolted onto the flat nose of the boat to allow it to double-up as a recovery boat.
Bob.
Hi Chris,
Either of those shaft options work for me - I probably do have an M5 12’” shaft in stock and cutting it down to 11” is not a problem either.
When I go home next, I will take a look to see what shaft length I used on the Sprite Plus. I probably stayed with the shaft length drawn on your plan.
Positioning the water-cooled alloy motor mount over a bulkhead worked well on the Sprite Plus - more work and a little head scratching at first - but once completed, it made a very strong integrated platform that included the bulkhead.
I will be using the same size and type of mount again, so if your motor mount template is the same as the one you used on the Sprite Plus, it will work perfectly.
Bob.
That’s a good point Chris - not too many youngsters are taking up model boat building and/or restoration as a long term hobby.
Bob.
Bob.
You guys are such perfectionists—it makes my heart race!
I’ve had other work to attend to lately, but now I’ll be back among you
and bombarding you with my progress reports...
That’s how I planned it, because things usually turn out differently than expected.
We send you greetings from the remainder of our vacation
(though as pensioners, one doesn't have a vacation—just a different kind of free time...).
Your Michel-C.
PS: There are no lakes or ponds nearby where we are, so—with his permission—I’m taking my grandson’s airplane along.
This Blériot glides and cannot crash, unless the transmitter is operated incorrectly. 🤣🤣🤣🤣🤣🤣🤣
And . .I miss my ships so much . . .🤧🤧🤧🤧🤧
This is the space over the front cabin that needs a lift-off roof making to cover it.
Bob
When talking posh I was alluding to the cockpit roof screen and console. But with the increase in size there is more scope for enhancements and they will look good. Nothing bodgy about your workmanship!
The wheelhouse roof for the LesRo Rapier - as supplied in the kit - is just a single bent piece of plywood skin glued over the top of the wheelhouse sides.
That’s it - just about as simple and basic as it could get, and it looks really poor.
When I restored Rapier 1 during lock-down, I put a decent fitted removable roof on it and as well as providing much better access, it also looked a lot better.
What surprised me was the amount of small formers that needed to be made and fitted onto a decent baseplate before it could be skinned .
This “improved” roof cover needed somewhere to sit, so that needed a bit more “bodging” to be done, so compared to the original kit’s one piece wrap of ply skin, it became a comparatively complex construction ..but to be “posh”. It would have had to have been made by a craftsman - not a bodger!
My roof making reached slightly better levels of fit when I made them for Rapier2 , Kopy Kommander and the Swordsman where I enjoyed the challenge of making them fit so well and so tight that a thin layer of sanding sealer was enough to make it almost impossible to “force fit” the cabin tops on, and almost impossible to pull them off.
Subsequent sanding has made them a more reasonable fit that is tight enough not to lift off at high speed, but loose enough to be able to lift off with enough suitable resistance to feel like it is still a nice tight fit.
If I can, I would like to make a lift-off cabin roof for the Sprite Plus that also fitted nicely enough not to fall off at high speed, but first I have to determine the shape that would look best .
Bob.
I have been giving the cabin roof design some though - and need to make up my mind shortly so I can get some wood cut and start the assembly.
At first, I considered the idea of having a slightly pointed roof with a central joint running along the apex from front to back.
More recently I have thought that a slightly rounded roof shape would look better and that is probably the way to go .
I will need to make some formers to make a small fixed cabin roof area towards the rear of the cabin opening to give a matching fixed area for the removable top section to fit back against, and also perhaps to provide a base to mount a cockpit windscreen onto?
This fixed cabin area could also extended back into the cockpit a little too to provide some sort of a dash board to further support the cockpit windscreen , and maybe (at a later date) provide an area to mount an instrument panel and steering wheel onto etc as well.
The front pointed part of the cabin will also need formers to be made that have a constant curvature with those at the rear of the cabin.
Once all the above has been decided and fitted, the base for the removable section of the roof can be cut and fitted with formers with the same curvature as the fixed parts of the roof structure.
Once all the above is completed, I can skin both the fixed and removable sections of the roof with the same curvature - and hopefully make an almost invisible joint between them.
The pointed roof option is still alive and is how I made the Kopy Kommander cabin roof pictured here.
A similar construction is currently being made to fit on the Rapier 2, and was used on the Javelin, KopyKommander and Rapier 1.
Bob.
Can you “almost intend” to balance the water-cooled motor mount on a bulkhead in the Swordsman 37 Chris?
……..is has worked-out beautifully on the Sprite Plus !
…..all those extra bulkheads - maybe one of them has drifted into the engine bay in exactly the right place…………..
Bob.
I've only had to drill the hole for one prop shaft. That was for the Fisherman as I used a solid mahogany keel. I only had a couple of mm each side to play with and did manage to break out of the side in one place but soon sorted. Had to buy a longer drill for that job.
I usually use the doubler method and file out each one to give some room to manoeuvre for the prop shaft. Once one doubler is glued in place I saw through the keel a bit wider than the prop shaft and then fix the other doubler. I then use the same method as Bob for fitting the motor using a solid connector and whilst fitted in place epoxy the prop shaft in. Much better than drilling and less stressful!
I think that accurately boring the long prop shaft hole through the keel is probably one of the jobs that most builders enjoy the most (!) - and that is probably the job you are referring to?
Aligning the motor with the fitted shaft becomes easy when a solid coupling is fitted between the prop shaft and the motor shaft.
With the motor already fitted to its mount it is often quite easy to slide a suitable piece of 1/2” thick plywood under this suspended assembly, and work-out the shape of the supports to fit between it and the lower skins.
I enjoyed making the motor mounting platform for the Sprite Plus as a bulkhead passed under the motor mount at exactly the right height to support the water-cooled alloy motor mount that I was using - thanks to the actual type of mount that I was using being accurately drawn on the plan by Chris.
This made it easy to include this supporting bulkhead as part of the motor mounting plate, so the plate was divided into two parts and fitted on either side of it, making a really strong integrated motor mount.
I added a pair of “spats” on either side of the mounting to further bond the two halves of the mounting platform together . These spats were also bonded to the bulkhead where they crossed it and were shaped to the angle of the bottom skins, so everything was fully bonded together.
This is probably one of the strongest motor mounting assemblies that I have ever fitted into a model power boat, and I am really pleased with it.
Bob.
I made a pair of 6mm “spats” to fit on either side of the completed motor platform to completely unify the assembly together.
Bob.
Bob.
The combined sandwich of bulkhead with the fore and aft motor plate has made a really strong integrated motor platform that I am really pleased with.
Bob.
As you say it is the prototype build! All part of the fun!
It just happened to rest on the bulkhead that crosses the engine bay in the correct position, so the motor mounting plate will be made to include this bulkhead as part of the sandwich with some of the platform in front of it and the other part behind it.
Bob.
Initially I will position the LiPo battery (the only significant movable weight in the hull) to give a similar weight distribution ‘fore and aft” to the Kopy Kommander/Remora/Rapier that I currently run the most as they all drive really nicely.
The boat will have plenty of power to lift the bows during the test run if I get it wrong, but I am hoping that it will drive as well as Les Rowell’s other designs and that the first run will be “incident free”.
Extending the length of the original Sprite design should not make any significant difference to its handling - although the increased size should make it more stable.
Bob
The way that Chris leaves a space for the rudder position in his keel drawings forms a helpful square shaped hole that only needs to be bored-out to fit the rudder, and its extended height supports the rudder shaft better than any other power boat I have built previously.
The prop shaft slot was opened out to fit the 5mm shaft and was bonded into position with 24hour Araldite epoxy resin…the rudder mount was also epoxied into position at the same time.
I had added an oiling clamp to the shaft, so this had to be loosened and slid up and down the shaft as it was pushed into the hull before being tightened into its final working position.
Next step is to make and fit the engine mounting baseplate. This will be a bit more “interesting” than it would usually be as there is a bulkhead that will need to be straddled by it, so the base will be split into two parts with this bulkhead becoming and integral part of the baseplate.
A solid coupling of the same length as the flexi coupling that I will be using will be fixed onto the end of the shaft and the motor to make sure of the alignment as the motor base plate is made and fitted into position.
Bob.
The bottom skin templates were made from cereal packets joined together with masking tape to make them long enough.
Once happy with the shape, I drew around them with a Biro and cut a pair of them from 1.5mm ply skins using a Tamiya razor saw and then test fitted them to the hull bottom.
The skins were then glued and fitted to the hull bottom and held in position with small clamps around the outside and brass nails into the bulkhead frames and keel until the PVA glue dried overnight.
Whenever possible, I prefer to fit BOTH SIDES of the bottom skins during the same building session to help avoid any twisting of the hull as they dry.
Bob.
The cabin sides remain exactly as Chris drew them.
Bob.
On the original Sprite the cabin front was flat.
On the Sprite Plus it was changed to a two part angled screen that will look better on a larger size version of the Sprite.
The front cabin spacer/window frame former was made the same width as the engine bay firewall and shaped to accept the two halves of the cabin front. This was glued between the cabin sides at the front top part of the cabin.
The windscreen was drawn onto the new cabin fronts and cut-out before being glued into position.
Since the cabin front was not longer flat, I though it would be nice to add a little shape to the foredeck so that was no longer flat and so some formers were laid onto the solid tops ready for the deck skin to be added later.
Bob.
The cabin will be visually extended forwards to some extent once the vee shaped windows are fitted.
Will
At this stage I decided to extend the length of the fuselage sides to fill the gap left between where they end and the next bulkhead.
On this prototype build I simply added these extensions using some 4mm birch ply.
I understand that Chris will extend the fronts of the cabin sides on his own build to save adding these separate extensions in as I have done.
As these extensions were added at a later date, I decided to extend them all the way down to meet the bottom skins so they could be shaped and glued onto the skins to make a solid box section.
Bob.
Lots of clamps were used to add the second row of obechie stringers to the first row to laminate and double the size of them to 1/4" square.
The laminated stringers are much stronger than a single piece of 1/4" square obechie would have been, and were MUCH easier to fit.
All of the stringers were cut to the correct length where they over-lapped the transom and the surface was sanded smooth - before covering the transom with a piece of scrap 1.5mm ply skin.
This transom cover was clamped all the way around and several brass tacks were also used in the middle to make sure it became a tight laminated outer cover.
The brass tacks heads were all cut off and the shafts driven down into the skin surface to cleat them and to fill their own shaft holes.
Bob.
The first row of 1/8" x 1/4" chine and the gunwale stringers were added next and were held in place with elastic bands.
The hull is now beginning to take shape.
Bob.
The keel and doublers were cut and glued together in the usual way and the bulkheads were slotted onto the keel in the 4mm space that was left between the doublers - followed by the cabin sides.
Everything inter-locked perfectly.
Bob.
I am really pleased with it, and I am happy that you have also decided to use it for yourself to mount your outboard motor on as I think it looks absolutely “right” with your chosen outboard motor on the (modified to fit) stern of the Sprite Plus.
I had already started the build before your idea about the curved cabin sides was added, but I am happy with the straight sides on the prototype as I think that it suites this punt bowed boat very nicely and that it also compliments the original LesRo Sprite - even though we have changed the windscreen shape…….
I am certain that they will both look and drive very well, and the integrated construction will be water-tight and able to withstand reasonably rough water without failure or leaks.
The weather is looking a bit “damp” next week, so I may be able to take another look at my Sprite Plus and get the engine bay painted so I can install the motor and ESC platform.
Once I have enough paint cover on the hull, I will test run it to check out its performance and handling and let you know how it runs.
Bob.
But you are right I usually prefer a lift off superstructure though in some of my builds since the Fairey sports cruisers I have used fixed. I did in fact start looking at lift-off for my Sprite Plus build but there were problems with doing that so I reverted to fixed which was reinforced for the outboard version as less access was required, particularly in the cabin area.
As well as the modifications for the outboard I took the proposed angled cabin/ coaming sides a stage further and curved them.
To be honest I wasn't sure in the end about building an outboard version of the Sprite Plus and drew up some plans based on the Sports Fisherman using the modified Stiletto/Rapier hull. But having looked at the plans again for this thread it's got to be done hasn't it! The Sprite Plus is so different to any of our other builds! But none of these drawings will be wasted as they can be used for prop driven models if needs be. Then again? Doh!!
Just prior to this a centre line was added to each bulkhead shape and it was folded along this line just to ensure that each template was perfectly symmetrical (old habits die hard), and they were !
One of the original bulkhead drawings was intended for the boat to be built with a “lift-off” superstructure, but I wanted my version to have an “integrated” build with access to the hull via a removable cabin roof and a removable rear aft compartment floor, so the bulkhead around the cab area needed to be joined together at the right height.
The correct height for the modified bulkhead was taken from the drawings, and it became a solid bulkhead with no cut-out as it would become the engine bay firewall and the front wall of the cockpit.
These two patterns were carefully taped together where needed but the overall shapes remained the same.
Bob.