beautiful sunny sunday

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Sandro Picchio
Posts: 94
Joined: Tue Dec 06, 2011 3:33 pm
Location: Lago Maggiore (Northern Italy)

beautiful sunny sunday

Post by Sandro Picchio » Tue Dec 24, 2019 6:34 pm

I was typing the draft of a replay to this thread when I noticed that the whole thread has disappeared.
The following is the text of my supposed post.

“The reasons of Chris are highly wise. I shall follow his suggested way and keep on seeing this forum, of course avoiding reading posts we now know by the name of the poster what can be the nature of the contents.
I think the best part of what is available on this forum is worth having to steer clear of certain threads.
I don’t like “being on the same page as the provider of the filth” either, but take or leave.
What I don’t understand is why someone uses this forum for such kind of chatting when there are probably thousands of specialized forums with more keen attenders.
May be it has to do with age.

Still hoping in an answer to the question in my post of yesterday.

Sandro

P.S.: sorry for expressing my feelings not properly because English is not my mother language.”


I wonder why the thread has been removed, as well as previous Grumpy’s thread “two for C”. There was nothing inconvenient nor detrimental for the forum. The honest and gentlemanly discussion was very interesting.

All this saddened me. But never mind, not many centuries of life are left to us, so let’s go back to our boats and our fickle little engines.

Merry Christmas to all

Sandro

Chris B
Posts: 70
Joined: Tue Jan 29, 2019 2:37 pm
Location: England

Re: beautiful sunny sunday

Post by Chris B » Tue Dec 24, 2019 8:21 pm

Sandro -

No need at all for you to apologise for your English. It's better than a lot of English people's English!

It's not an easy language to learn either. Being a hybrid language a lot of it is confusing, contradictory and illogical. I'm 100% English and was born in England nearly 70 years ago - but I consider myself to be learning the language still! And your English is 1000 times better than my Italian.

Ti auguro buon Natale!


Chris

Sandro Picchio
Posts: 94
Joined: Tue Dec 06, 2011 3:33 pm
Location: Lago Maggiore (Northern Italy)

Re: beautiful sunny sunday

Post by Sandro Picchio » Wed Dec 25, 2019 12:20 am

Grazie Chris. Ricambio gli auguri a Te e alla tua famiglia.

For what I can see your Italian is super.
It's the subject that makes me unsure of expressing my thoughts. When it is matter of cylinders or carburettors or rigging I am much more relaxed.

All the best

Sandro

Chris B
Posts: 70
Joined: Tue Jan 29, 2019 2:37 pm
Location: England

Re: beautiful sunny sunday

Post by Chris B » Thu Dec 26, 2019 3:26 pm

Sandro - do you by any chance happen to own a pretty little Dabber called Giulia (in English that would be Julia) with a blue hull and tan (brown) sails?

If so, I've seen some of your woodwork and rigging ideas. All very carefully thought out and beautifully done. My own boats have all been traditionally rigged and I'm currently converting my sloop to a yawl. You and your Dabber - if it is indeed you and Giulia is yours - deserve congratulations because it's a work of art.

Chris

Sandro Picchio
Posts: 94
Joined: Tue Dec 06, 2011 3:33 pm
Location: Lago Maggiore (Northern Italy)

Re: beautiful sunny sunday

Post by Sandro Picchio » Fri Dec 27, 2019 12:58 am

Yes, that's me.
You are too kind about my little works and make me blush. Actually I should care better of the aesthetic side as painting and cleaning.

Among the good things of owning a boat there are not only sailing her but also planning, designing and making all the changes which one thinks better suitable to his own needs and taste, improving the pleasure, the conveniency, or the safety of his proud and joy, (and of the trailer and launching drill) in addition to the normal maintenance and repairs.

It's a pity now I am doing too little sailing. When my children were boys the occasions were much many and with a good crew. Now also the grandchildren begin growing too old. But also studying the triks for singlehandling is part of the pleasure.

All the best

Sandro

Chris B
Posts: 70
Joined: Tue Jan 29, 2019 2:37 pm
Location: England

Re: beautiful sunny sunday

Post by Chris B » Fri Dec 27, 2019 12:04 pm

I'm in accord with you on the importance of detail Sandro. For example, when I bought my sloop (soon to be a yawl) I dumped the builder's standard layout for the accommodation, and fitted it out to suit my requirements. The original designer had intended it to be 4 berth and his standard arrangement used a lot of factory-made GRP mouldings. But I reduced it to 3 berth, refused to use the GRP mouldings, and used a lot of solid mahogany instead. Those changes allowed me to have a full size chart table / navigator's station, the galley is tucked away in its own space (instead of "open plan" and in the way) and the result is that boat feels quite a lot bigger inside than it would with the standard layout. The varnished mahogany joinery gives a warm and solid feel - a feeling of quality and tradition - which I like very much, and prefer to the standard (although much easier to fit and maintain) GRP internal mouldings.

And I promise you that I didn't waste any trees! Nearly all of my mahogany was recycled from a very old country house that had sadly been abandoned and was eventually demolished, so the old mahogany was high quality and had been peacefully seasoning in-situ for a couple of hundred years! In a couple of locations in the boat where there is high wear and tear (the companionway sill, for instance) I've used teak. But even the teak was recycled, because I used large offcuts - wastage - from a nearby factory that makes teak furniture.

The work took a few years and the project is ongoing (boats are never really completely "finished" are they?) but it was worth it, because I've ended up with exactly what I want, instead of what a designer who has never met me thinks I should want!

Same philosophy applies to the rig. I've always preferred single-handed sailing and have rigged all of my boats with that in mind. Hence the yawl rig, which might look old fashioned to the modern eye, but I find it visually attractive and excellent for single-handed offshore sailing.

And then there's the Seagull outboard which is part of the same boat's equipment. I chose the Seagull because it looks right, sounds right - and somehow even smells right, for this boat and the era that the boat represents. But even the Seagull hasn't entirely escaped a bit of modification and customising. Purist Seagull owners probably won't approve of this but I'm going to confess that I got rid of the plastic choke shutter and, having widened the shutter slot in the air intake cowling, I replaced the old plastic shutter with a new one machined from 2mm stainless steel plate.

Incidentally, on a point of detail, I designed the new choke shutter so that it works in the opposite sense to Seagull's original version. When the new shutter is closed, the choke is in the "run" position, and when the shutter is open (i.e. fully visible) the choke is in the "start" position. It was simply a case of changing the position of the choke aperture on the new shutter. I also included an unobtrusive leaf spring (hidden on the carburettor side of the intake) to help keep the choke shutter open / closed / or somewhere in between. I think the result looks nicer - neater - than the original, because when the engine is running the new shutter is tucked away in its slot, which also makes it less vulnerable to accidental damage.

Always nice to get things the way we want them on our boats. Getting it all right takes time though!

C

Sandro Picchio
Posts: 94
Joined: Tue Dec 06, 2011 3:33 pm
Location: Lago Maggiore (Northern Italy)

Re: beautiful sunny sunday

Post by Sandro Picchio » Fri Dec 27, 2019 9:42 pm

Being surrounded by warm varnished mahogany gives a completely different comfort than by bathtub white GRP. We must admit that nowadays GRP is so convenient for the hull (let’s be practic, a carvel or clinker wooden boat is wonderful but too much demanding) but down below the less GRP is in sight, the better.

What a stroke of luck the old house timber salvaging!
One should have lot of indoor room for theese occasions. I saw huge old oak beams being degraded to fire wood but could do nothing.

Your opinion on the architect/end owner relationship is very true and applies also to houses.

Yawl rig. In my instance it is not the case of splitting few big sails in more smaller manageable ones. People hardly believe me when I say my 15’ 6” boat is a “two mast” but she is.
I don’t think my mizzen is of much help concerning power but I use it for handling the boat in way of steering and turning. E. g. tacking with too little wind she can remain in irons. Not so if you tighten the mizzen until head to wind and then quickly slacken it allowing the stern coming up windward. Also the jib must be tended, the other way round and backing it a bit.
The mizzen allows balancing the boat without using much helm and consequent drag.
It is the last sail to be lowered on a mooring, keeping the boat head to wind.
When I crew on a sloop I miss it.
It keeps you busy at sea and gives more chances to experiment and learn new seamanship techniks.

My Seagull 40+ choke shutter being from 1963 is metal, there is no need to replace. I did not understand where your shutter conceals itself when open. Under certain conditions it's a good thing to be able to partially choke the motor.
I had to replace with an M6 brass bolt the plastic pivot of the hook holding the motor tilted, which snapped.
No other modifications except two holes in the wings of a clamp screw (not a serious sin I hope) for fitting a fork into which to lower the tiller for holding the motor straight and steering by the boat rudder. The fork position is adjustable by wing nuts for an accurate straight heading steer angle, that changes with speed, wind, load, load position, etc.
The swinging braking nuts are just hand tightened, if a maneuvering need arises one just lifts the tiller and the motor is free.

I used this Seagull in Giulia for a good few years but it was a little underpowered for the boat. So, not least for the appeal of a neutral clutch, I bought a Jonson 4 hp two strokes which was overpowered and rather heavy. Some years ago I found a second hand Yamaha 3 hp Malta (two strokes) that is the present suited engine of Giulia.
Also for the Malta I fabricated a temporary clamp for the tiller, as the screw adjusting the steering friction is hardly reachable down the well. I lengthened the clutch lever so it can be managed on top of the motor when reversing. I pierced the lower cowling and distorted the air filter in order to reach from outside the carb bowl draining screw.
I would like to switch from time to time between the Yamaha and the Seagull but It is not possible without paying two insurances.

I would be glad to see a picture of your sloop - pardon me - yawl.

Sandro

Chris B
Posts: 70
Joined: Tue Jan 29, 2019 2:37 pm
Location: England

Re: beautiful sunny sunday

Post by Chris B » Fri Dec 27, 2019 10:29 pm

Hi again Sandro -

My previous boat was a yawl also, but the one before that was a ketch. That was a big, heavy boat (15.8 metres) but the ketch rig (plus a 140bhp Gardner 6LX diesel) made it possible to sail her single-handed without working up too much of a sweat. Mind you, I bought her in 1986 and I was a lot younger then (and fitter too) so I'd probably find her much harder work these days! I've downsized since then, so as not to do myself too much damage due to over-exertion on deck!

I should perhaps add that whilst the rig didn't require much muscle power at all once the boat was actually sailing, the sails themselves were real canvas. This made them quite heavy to manhandle when they were dry - but when they were soaking wet they became a bit unwieldy for one person. Reefing the main in a blow (with traditional reef points) especially when it had been raining heavily, was quite hard work!

I entirely agree with your comments about the handling advantages of a yawl. Apart from helping to get her through the wind when changing tack in a gentle breeze (to do that, I heave the mizzen boom across to the weather side and hold it there until the boat's gone through the wind - it works a little bit like an aircraft rudder), I find the mizzen makes it possible to perform manoeuvres under sail in confined spaces, that simply couldn't be done with a sloop or cutter. And, as you pointed out, the mizzen on its own turns the boat into a weather vane, helping her to lie comfortably head to wind - which can often be very useful when sailing single-handed.

On the academic side, one result of changing my rig from sloop to yawl is that the centre of effort of the sail plan will try to move aft, in this case well behind the hull's centre of lateral resistance. You're no doubt aware that would be undesirable, so to balance the new mizzen (and return the CofE to its correct location relative to the CLR) extra canvas will be required on the fore-triangle,

I'll achieve the required adjustment to the CofE by adding a flying jib and a bowsprit. My sail plan calculations indicate that the bowsprit will need to extend 1.7 metres beyond the bow, and its total length will be 2.8 metres . The bowsprit will be made of Columbia pine and will be retractable - otherwise my mooring charge in the marina will increase!

I think I should still have some photos of the accommodation on an old laptop somewhere, or possibly on a disc. If I can find them I'll let you have a look.

Regarding your question about where my Seagull's new choke shutter hides itself: it hides in the normal place - inside the slot in the inlet cowl. However, the way my shutter works is the reverse of the standard arrangement. I'll try to explain with a bit of detail....

So - as you know, with the standard Seagull choke arrangement, when the shutter is sticking up, the choke is "off" and the engine is running without choke. And when the shutter is down in its slot, the choke is "on" for starting.

However...

I've reversed the standard Seagull arrangement and have configured my stainless choke shutter so that once the engine is running, the shutter is pushed down in the slot, to take the choke off. This means that when the engine is running, the shutter is neatly stowed down in its slot and out of the way. Thus my choke shutter is only pulled up out of the slot and exposed when starting the engine.

29-12-19. P.S.
In case you're wondering how I managed to reverse the way my choke shutter operates, the new shutter has two apertures in it, one above the other. The top one is a large hole for "choke off", and the lower of the pair is a small hole for "choke on". The standard Seagull shutter has only one hole, for "choke on".

Chris

Chris B
Posts: 70
Joined: Tue Jan 29, 2019 2:37 pm
Location: England

Re: beautiful sunny sunday

Post by Chris B » Tue Dec 31, 2019 5:39 am

Apologies... Re. choke shutter modification mentioned in previous post, I forgot to mention that the choke mod was for a WSPCL with the Amal 46NE carburettor and standard inlet cowl.

C

Sandro Picchio
Posts: 94
Joined: Tue Dec 06, 2011 3:33 pm
Location: Lago Maggiore (Northern Italy)

Re: beautiful sunny sunday

Post by Sandro Picchio » Wed Jan 08, 2020 11:46 am

Hi Chris,

my sails are boomless, so I can’t use the mizzen as you do in tacking, I back the jib instead. Otherwise many funny manoeuvres could be performed, like moving the boat in “reverse” stern first.

You surely will need more sail afore to balance the new mizzen. Will the new retractable bowsprit be sliding along its axis or hinged like a Thames barge’s? In close quarters a bowsprit is a threat; I quickly withdraw my tiny one as soon as I approach any jetty or boat.

Choke. I see now. In my mind I was referring to my Villiers carb. In this one there is no room for the small hole section below the carb air passage when choke is “off”.

Sandro

Chris B
Posts: 70
Joined: Tue Jan 29, 2019 2:37 pm
Location: England

Re: beautiful sunny sunday

Post by Chris B » Wed Jan 08, 2020 2:46 pm

Hi Sandro.

Mizzen... When I'm single-handed and depending on the conditions, I put the helm over and back the mizzen, leaving the jib as it is for a few moments during the tack. The main of course looks after itself. As the bow goes through the wind I release the mizzen, ease the helm and finally sheet the jib for the new tack. If the sequence is executed in that order there's plenty of time, the boat helpfully plays the game, and it all only requires two hands.

A mizzen is, as you've observed, very handy for manoeuvring in reverse because if conditions are favourable it can be used to pull the boat along backwards. With a bit of practice and an understanding of how a particular boat behaves, it can also be used to help turn the boat in little more than its own length.

On a small boat in a gentle breeze you can do the same thing with a loose footed mizzen by temporarily hooking a pole between the mizzen's clew and its tack. It's effectively a makeshift boom. A telescopic boat hook can be persuaded to do the job. Only suitable for a light breeze though, because if the inboard end of the pole dislocated itself in a strong breeze it might do damage!

When anchoring in a strong breeze, I'll sometimes use the mizzen's "reverse gear" capability to get the boat moving astern and help set the anchor in the ground.

Bowsprit hazard... When manoeuvring in confined spaces I don't regard the bowsprit as an unwieldy extension. Instead, I think of it as part of the boat's total length. That way it gets included in the space requirement, instead of becoming an inconvenience - and possibly turning into a dangerous weapon with a few tonnes of momentum behind it!

Rigging the bowsprit... The heel of this new bowsprit (i.e. the inboard end) will sit in a "U" shaped stainless steel shoe / thrust block, with a transverse retaining pin. There will be a similar locating shoe on the stemhead, but with no retaining pin. A retaining pin here would turn the bow fitting into a hard and unforgiving fulcrum, whereas an unpinned fitting allows the bowsprit a bit of vertical movement, thus letting it "work" a little as the load from the flying jib changes.

The bobstay will have an inhaul running over a turning block near the outboard end of the bowsprit, tensioned via a gun tackle on the foredeck. The fall of the gun tackle is made fast to a dedicated cleat. This arrangement allows the bowsprit to pivot upward when required, rather like the setup you mentioned on a Thames barge. Alternatively, the bowsprit can be easily unshipped by one person and stowed in chocks on the coachroof.

C

Sandro Picchio
Posts: 94
Joined: Tue Dec 06, 2011 3:33 pm
Location: Lago Maggiore (Northern Italy)

Re: beautiful sunny sunday

Post by Sandro Picchio » Sat Jan 11, 2020 12:02 am

Hi Chris,
Tacking…I see that experiencing and playing about two mast boat’s tacking brings to very similar drills unregarding latitude.

Bowsprit…the danger I meant was mainly for the thin bowsprit itself.

Rigging…I can imagine what a gun tackle can be (the two tackles to reposition a Nelson time gun after a shot?) but what is its common meaning nowadays?

Sandro

Chris B
Posts: 70
Joined: Tue Jan 29, 2019 2:37 pm
Location: England

Re: beautiful sunny sunday

Post by Chris B » Mon Jan 13, 2020 7:07 pm

Hi Sandro,

Yes, the gun tackle's name stems from its once common application of moving heavy gun carriages on fighting ships.

It's a simple but useful tackle: just 2 single sheave blocks, giving a mechanical advantage of 2:1.

If you take HMS Victory as an example, the largest guns fired a 24 pound shot but the gun plus its carriage weighed more than 3 tonnes. The carriage had a gun tackle on each side, and although each tackle only offered a 2:1 advantage, each gun crew comprised 12 men, so there was plenty of muscle power available to man each tackle.

After loading the weapon, the gun tackles were used to haul the gun outboard to its firing position. When the gun was fired the explosive recoil automatically brought it back inboard again (mind your toes!) ready for reloading.

An experienced gun crew could complete the load and fire cycle once every 90 seconds.

C.

Sandro Picchio
Posts: 94
Joined: Tue Dec 06, 2011 3:33 pm
Location: Lago Maggiore (Northern Italy)

Re: beautiful sunny sunday

Post by Sandro Picchio » Mon Jan 13, 2020 10:49 pm

Hi Chris,

thanks, that's what I had thought - not so difficult, by the name.

If the tail (or bitter end or what's its name) of the tackle comes from the moving block the advantage is 3 : 1, but probably this was not the case for the gun application because 6 tugging men in line hardly had room between gun and gunwale. More likely lining towards the centre of the deck.
I think another function of the gun tackles was to dampen the recoil movement by friction.
The speeds of ball and gun are inversely proportional to the masses, so the recoiling initial speed of the carriage is 11 kg / 3000 kg = 1/273th of the speed of the starting ball. I don't know this speed so I must stop here.

Sandro

Chris B
Posts: 70
Joined: Tue Jan 29, 2019 2:37 pm
Location: England

Re: beautiful sunny sunday

Post by Chris B » Tue Jan 14, 2020 1:20 am

Sandro -

Well, muzzle velocity would obviously depend on the size of charge used, but I gather that a bronze 32 pounder naval cannon could withstand a detonation load capable of producing a muzzle velocity of approximately 450+ metres/second.

And if you run the numbers for the mass and momentum calculation and consider the result, it will probably come as no surprise that at short range and zero elevation, a 32 pound iron cannon ball had sufficient energy to punch a hole through oak approximately 1 metre thick.

However, I would imagine that with a similar muzzle velocity, and of course depending on the height of the gun above the waterline, you'd probably need to be quite close to your target to pull that off. I say that because, according to Isaac Newton, horizontal and vertical velocities are independent of each other, and in our ballistics situation the vertical acceleration component will be 1g. Which in round and rough figures leads us to infer that if the gun is roughly 5 metres above the waterline and fired with zero barrel elevation, then - and entirely regardless of its muzzle velocity - the cannon ball will hit the water approximately 0.5 seconds (only half a second!) after it exits the gun barrel.

So with a muzzle velocity of 450 metres / second and making an allowance for air resistance, if you're hoping for a direct hit above your target's waterline, you'd probably need to be within less than 220 metres of your target before opening fire. However, as the larger guns were on the lower deck, the vertical distance to which the 1g acceleration is applied would be a lot less than 5 metres, so you'd need to be correspondingly closer. I'm only thinking this out in very approximate terms as I'm writing this post, but it possibly gives some idea of was going on. This, of course, only applies to zero elevation at short range, for maximum penetration on impact.

Either way, being on the wrong end of the result could seriously spoil one's day.

Regarding the rigging and use of the gun tackles. The block at the inboard end of each tackle had a becket with a forged hook, and the hook engaged with an eyebolt on the side of the gun carriage. As you've observed, the tackles were left rigged during firing, so that the recoil energy absorbed by the tackles' frictional losses had a useful damping effect on the recoil. The absorbed energy would be converted into heat within the tackle's hardware and then subsequently disperse. That apart, the recoil distance itself was limited by a heavy manilla restraining rope, which was secured to the breech and arrested the recoil movement when the muzzle of the gun was about 0.5 metre inboard of the gun port.

Apparently, if somebody was sufficiently mad to require an advance warning of what hell is like, they just needed to stand on the lower gun deck of an 18th century naval ship during a close quarters sea battle...

C
Last edited by Chris B on Tue Jan 14, 2020 2:15 pm, edited 3 times in total.

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