28 foot Ranger type yacht by Mark Pearse - 1:12 - FINISHED

[Mark Pearse]

Hi Row

 

my thinking is for 2 reasons: to help stabilise the hull shape, & also to make the planking process easier in a part of the hull that might be difficult. The lower part of the hull is full forwards & slims out aft to an extension of the keel, so the planks that have to do this transition will probably have a fair bit of tension. The area I'm concerned about is the stern, up to about the top of the turn of the bilges.

 

If, for say the last 4 or 5 moulds, I cut away the lower part of the plywood & insert of 4mm thick solid piece of timber to the same profile, the planking can be permanently fixed to the timber & I will know that it won't distort. It's not much work to do it, & I suspect it will make the planking much easier as I can face fix the planks to the blocking pieces.

 

Here is a sketch to show the idea more clearly than I have described, plus a photo of our own boat Cherub - a similar hull shape - that shows the relevant area, where the lower planks at the stern are close together, below the turn of the bilges.

 

 

 

 

 

 

 

 

 

 

[Twister]

Mark,

 

Fully understand your reasoning now - clever solution to a potential build problem, it's almost a 'half' POF I guess.

 

It appears from your photo of 'Cherub' that you've been busy re-caulking the garboards - not the most pleasant of tasks but very necessary...  Also, 'Cherub' appears to have some of her keel cut away aft not shown in your drawings or photo's on the first page, is that something peculiar to her particular size or was it a modification to improve helm balance or simply part way through a repair?

 

Looking forward to seeing how you progress with this,

 

Regards,

 

Row

[michael mott]

Mark that looks like a very good solution.

 

Michael

[Mark Pearse]

thanks all, it's very helpful to get the comments

 

Row, yes the stern part of the keel was cut away, Ben Lexcen (designer of Australia II) was a mate of the original owner, & when Cherub was converted to Bermudan rig she initially didn't perform well, Ben had a go & added some more lead & did the cutaway. She tacks faster but probably has a heavier helm as a result. The garboard plank is hardwood & had been leaking pretty badly - we glued hardwood strips on to the edges of the plank to bring the seam back down to a sensible size for caulking. We were converting her back to gaff rig & improved the balance with a longer bowsprit rather than by adding lateral resistance aft.

 

I have realised that I need to work up a drawing of the boat to get the lines right - I can't confirm if the transom shape is good without checking the lines. My first go is below, but the stern section is definitely a bit flat, it needs to kick up a wee bit at the stern lines.

 

I'll work on this a bit more before finalising the transom on the model.

 

 

bye for now, MP

[Jim Lad]

Love that profile, Mark!

 

John

[Mark Pearse]

I checked & the transom height that I used previously was wrong, & with the correct height the lines are much better. They will be done by eye on the model, but I need to know that the height of the transom/gunwale intersection is good.

 

Much better, I am going to proceed with this

 

[Mark Pearse]

A little more progress - I shaped & fitted the stern knee (sorry, not sure what it's called), & fitted a removable temporary transom.

 

The stern knee has been roughly shaped & the rabbet approximately cut, a bit more shaping required but after the fairing has been done. The lower edge of the garboard plank will lie along the underside face of the keelson. The knee was, as before, pinned with brass rods & glued with epoxy, I find that this technique allows a good cleanup as there's no clamps in the way, & it will all stay where it's supposed to be while you do it. The pins are clipped off & sanded flush afterwards.

 

 

The transom is removable & temporary because I sense that I will need to adjust it a little, it has to look good - sort of like the final chord in a great piece of music. A good solid structure to hold the transom was made, which will have some pieces fitted to hold the transom accurately in place.

 

 

thanks for watching, bye for now

MP

[Mark Pearse]

I've done a bit more: the solid lower bulkheads aft have been cut & glued in, & the inner part of the keel has been faired. I'm satisfied that these solid pieces will help, perhaps if I'd planked a model boat before I would know if this shape would work without them or not, but for a small amount of work I'm making it a bit easier to get that important part right. To me, the most important part of the hull shape in these boats is the water exit lines. It's not an accurate scale version of the way the hull would be constructed, but the main objective is to end up with the right hull shape externally. Internally, if I'm happy with the logic, that's enough.

 

The solid bulkheads still need to be stabilised so that they stay in the same plane as their plywood bulkheads during the fairing process, & yet are able to be separated - for when I remove the ply later.

 

Next steps are:

 

- checking the temporary transom, & fitting pieces to stabilise it also for the fairing process.

 

- glue in more bamboo skewers generally, the brace the moulds & hold them rigidly in place

 

- temporary pin for the inner stem, same reason

 

Then I can fair the hull. I might also do a profile of the outer face of the stem & inner keel, I could do a fairly accurate template now while it's still removable. This would give the inner shape of the keel & outer stem for later.

 

 

In the photos, the inner keel is sitting up a bit - it does actually sit down flush on to the tops of the stations.

 

 

 

As an aside: I asked a boatbuilding friend about the piece I'd been calling a stern knee - he says this is the correct term. But he also said that my use of keelson isn't correct, there is such a thing, but apparently it sits above the ribs. So I'll call it "inner keel" for the same reason I call the stem piece the "inner stem", for practical model making reasons I've separated the stem & keel into pieces, divided along the rabbet line.

 

thanks, until next time

Edited February 6, 2015 by Mark Pearse

[Mark Pearse]

goodness how time flies...

 

Well I have done some more this week: final fairing of the keelson & inner stem; making the outer stem & the strip below the keelson. I have separated the stem & keel into parts at the planking rebate line, & I'm now making the outer pieces.

 

The keel piece will be screwed & glued to the keelson, & I put some of the screw holes right on top of previous brass pins, so I had to do some new ones - but I'll justify the extra holes by using them to pin down into the keel. I will need to pin the outer stem, for the same reason, that I'm always concerned that the pieces stay exactly where they are supposed to be during glueing. Also, these pieces have some twists etc that need to be taken out & the screws & pins help to remove the twist.

 

The keel piece is Queensland Maple, really nice quality timber from bunk support pieces from our boat. The timber is nice, fairly light but still quite resistant to dents. It curved quite well too, I used a heat gun to put some curve into it, so that I doesn't want to pull the existing structure up & out of shape.

 

I have shaped the underside edges of these strips to be perpendicular to the planking.

 

 

 

 

The scarfed joints between the pieces are not sound in themselves, but are more or less the correct joint scaled up - the actual stem forefoot piece would have been a grown Tea Tree (Melaleuca) knee piece, but there is no issue with strength here & it will be painted so I'm not going to try & replicate the curved knee in this case.

 

 

 

 

thanks, more soon I hope, MP

Edited April 27, 2015 by Mark Pearse

[mikegerber]

Hi Mark

Well done! It's great to see your project newly growing ...  

 

And yes, you're right: time goes by so quick and often we have to steal some hours for working on our builds. But fortunately it is not a competition - it takes as long as it takes. So, I'm looking forward to all your future logs - if time has come to ...

 

Best Regards!

Mike

Edited April 28, 2015 by mikegerber

[kees de mol]

I am amazed by your shipbuilding abilitys now allready. Looks very professional and well tought.

 

Regards, Kees

[Mark Pearse]

I am currently fairing the moulds & anything else that needs it - work now to be easier later hopefully.

 

The shape of the temporary plywood transom was ok - so I cut the actual transom from the 3mm Huon Pine. In this photo it still needs to be faired, so the will be a bit finer again. Also, you can see slight asymmetry, the fairing & planking will reshape it enough that I don't need to worry about that now. To me, the transom shape of a boat is absolutely crucial to a good looking boat - like the final chords in a piece of music - & it's good to see that this one is looking right for this boat. The shape is soft & gentle, but with the suggestion of the amount of volume that the hull will have - she is a day boat designed to carry reasonable loads, not a racing yacht.

 

 

The transom was pinned & glued. 

 

 

 

thanks for the interest, MP

 

 

 

[Mark Pearse]

some photos of a similar yacht to the one I'm building, designed also by Cliff Gale : Maluka, photos from the last Sydney-Hobart, seen here on a close reach in 25-30 knots rounding the Iron Pot entering the River Derwent at Hobart

 

nice footwear, too

 

 

 

 

 

 

[Mark Pearse]

The garboard plank is on, & I can now set out the rest of the planking. To set out the garboard I used the example of the 24' Ranger garboard plank, which goes forward about as far as the forefoot.

 

 

The reference

 

 

The notches are to take ribs, the rib spacing won't be to scale, my estimate of enough to help hold the hull together.

 

 

Edited May 23, 2015 by Mark Pearse

[Mark Pearse]

Hi 

 

I've been lining off the moulds for the planking using strips of balsa wood. The balsa has the advantage of being easy to cut into strips, easy to pin, & is fairly even in bending, but they are delicate & get damaged so easily.

 

The planks themselves will be about 6mm maximum width, or about 72mm to scale. The plan is to: finish the lining off; mark this on to the moulds; make final adjustments to the moulds. I hadn't thought that more fairing would be needed, but the balsa battens laid along the actual lines of the planking showed that there is still some wobbles. I mocked up an approximation of the curved cockpit gunwale capping piece in black cardboard, it's not obvious but you can see it in the photos. This is the line that the topsides will be trimmed down to after the area is planked.

 

You can see that a stealer plank is probably necessary, near the turn of the billed at the stern, I'm not sure exactly, but I think that where it wants to go will become clear when planking.

 

 

 

 

 

 

 

 

thanks, bye for now

 

MP

[Omega1234]

Hi Mark

 

I love the framework of the hull. It has a beautiful symmetry and gracefulness that's hard to describe. It'll be a shame to plank it, but plank it you must (of course).

 

She's certainly a real looker.

 

Cheers

 

Patrick

[Mark Pearse]

thanks Patrick & others,

 

I am looking forward to seeing the keel on, & might even do it sooner than later, so that I can enjoy the effect on being able to better see the hull shape

 

You can see clearly the way the water exit is clean despite the voluminous hull, it's my theory on why they sail well for a tubby boat.

 

MP

[Twister]

Mark, you really are doing an incredible job on Ranger; she looks absolutely stunning!

 

The time taken getting the fairing 'right' will pay dividends in the long run - I had it so much easier when building the mold for Enterprise knowing that copious amounts of filler would hide a multitude of sins...

 

Keep up the excellent work & I look forward to reading / seeing your next instalment.

 

Regards,

 

Row

[Jim Lad]

Just catching up, Mark.  She's really looking the 'cat's pyjamas'.

 

John

 

PS. By the way, I just noticed on your Sydney-Hobart photos of Maluka that the drew are sitting out in bare feet!  I know it was summer - but bare feet off the Iron Pot?

[dvm27]

Just found your build log, Mark. She's a beauty of a ship as well as model. Love your photos and techniques.

[Mark Pearse]

Hi there

 

I finished fairing the moulds & have done a few planks. The intention is to first do a band of planks from the top edge of the transom down, to help stabilise the whole thing. There are some planks above this line due to the raised deck design, . When there's what seems to be a stable band of planks I'll probably start planking back up from the garboard.

 

They are going on well, I've been using toothpicks at the stem & transom to help hold the planks in position - they will want to pull away under the tension on the planks, but the glue gets slippery & it would be a bummer if a plank slipped & set in the wrong place. The toothpicks act as pegs & hold the planks in place while the glue goes off. 

 

An interesting scale comparison is a new casting for our boom.

 

hanks

 

 

 

 

 

 

[Mirabell61]

beautiful built model Mark,

 

thanks for sharing youzr work and for the actual boat...

 

Nils

[Jim Lad]

Nice to see the planking started, Mark.

 

John

[Omega1234]

Hi Mark

 

Nice progress!

 

Cheers

 

Patrick

[druxey]

Just found this log. Lovely work so far, Mark.

[Mark Pearse]

thanks all for the encouragement, it is great to see a hull shape slowly appear

 

MP

[dgbot]

Mark how are you going to keep the planks even when the frames are so far aoart and the wood you are going to use? Inquiring minds would like to know.

David B

[Mark Pearse]

Hi David, the stations are about 60mm apart - a little under 2.5" - if this is wide then I didn't realise it in my lack of experience. But I'm confident that I'll work out something if it does become an issue. I can see a couple of possibilities: the planks are about 0.5mm thicker than scale, to allow for some of this; I might be able to work out some sort of jig to hold them in line while the glue hardens ... but I think that the run of planks are quite close to how they would be in reality, & the width is certainly about right at a scaled up width of about 70-75mm maximum.

 

The timber is very supple, so it will take shapes well without requiring heat - but if heat will help then heat it shall receive.

 

Any suggestions? 

 

thanks, MP

[Mark Pearse]

I've noticed that the planks spread a little away from the moulds, perhaps it's because there's only 3 planks per side on, but I decided to put in at least one full frame & deck beam now as it's going to be easier now than when more planks are on. If that doesn't seem to be enough then I may do more, but we'll see. The frame I chose to make is right at the edge of the raised deck. I cut some 10mm strips of hardwood veneer - Jarrah - & glue laminated them into shape by some judicious clamping & hopeful intentions. The photos show the starboard one clamped & glued in place, & also the port one afterwards, slightly sanded & clamped back in the approximate position. It's still about 8mm wide, which might be reduced, but in any case I never intended the interiors to be accurate to scale & construction so it's ok at that width. 

 

The veneers were quite easy to get into position, I was unsure of how difficult this would be, but it was quite easy & the resulting frame is good, stiff enough & also springy enough. Because the planking lines at this point of the hull swell outwards by perhaps 0.5mm, & the shape I made with clamps & battens doesn't have any of this swell, I hoped that they would be able to expand a little if I wanted, to suit the actual shape. 

 

 

 

Next is to make the deck beam, some simple knees & then glue it all together.

 

bye for now

 

MP

 

[michael mott]

Mark Great progress, I'm still catching up on a number of builds. I like the look of the ribs that you have installed as well. I really like the lines of this boat.

 

Michael