Originally Posted by DanL

lucc,
Here is a drawing of a keel rod supported by both the hull and deck.
Maybe you already have tried this.
Best,
Dan

Yes ,but my bolt is 6mm and is to weak. Under an angel off 90 degrees there is a force of 440 kg ,where the bolt come out off the kiel.
By 45° there is a force off 154kg on each bolt.
The leadbomb is 12kg and 330mm off the kiel.



My keel is strong enough to hold my bomb under 0°

but is to weak when she's going flat .

Stronger bolts, but this isn't easy when youre ship is complet finnished and very difficult to handle, Can't turn it over

lucc,
Maybe instead of 12kg that is 330mm down, try more weight very close to the hull.
Syren is only about 1.5m long and the lead keel weight is about 18kg. The keel is held on by 6.3mm threaded rods. So maybe you make a heavier keel and mount it directly to the hull? And add some weight inside the hull.
That would reduce the angular force quite a bit.

Another idea, maybe. Make an external mounting bracket for the lead keel, and attach it as shown in the sketch. The mounting holes would be visible when the keel is removed, but they would be small and could be disguised somehow.

Best,
Dan

You will greatly reduce the chance of a 90deg knockdown if you reduce sail before the wind picks up. Just like the real ships, our models respond to good (micro) seamanship. Most knockdown's I have experienced (due to not reducing sail in time) have been of the 70-80deg range, not 90deg.

The wind spills off the sails as the ship heels, reducing capsize force. In this regard, reducing the lead weight would help you by letting the ship spill wind earlier. Real ships had to check ballast calculations to be sure they would heel to spill wind before the shrouds were over-stressed, btw.
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Another idea for supporting your keel would be to run stays from the weight up to the turn of the bilge of the hull. These could be strong, no-stretch fishing line, eg. Spectra (no stretch if pre-stretched before installation). The attachment point for the lines could be small bolts, which would not be too noticeable if painted same color as hull. This is similar to DanL's recommendation, but uses trigonometry, instead of bracket strength, to support the finkeel's weight. The weight is supported by tension, instead of compression, so the hull strength would have to be checked. Remember, the effective weight of your lead bulb is reduced by the buoyancy of the volume of the lead. This reduction can be significant for small bulbs, or pvc pipe filled with lead shot.

btw, you might try the pvc-tube-with-lead-shot bulb as you experiment with your boat's sailing capabilities. You might find that, under the conditions you find at your pond, less weight down low would be perfectly acceptable.

These models all sail faster than scale speeds, so the drag of the fishing line stays would likely not be too noticeable. I have stays (running from a cross spar on the end of finkeel up to the top of the finkeel) on my sinkable ships (they activate the sinking mechanism when struck by a submarine). They don't seem to slow the sailboat targets at all, or at least that's what the sub skipper (Capt. Nemo) says. And my pvc bulb finkeels are primitive: the pvc pipe is lashed to the finkeel with ordinary string. The extra drag from the string (compared to a bracket attachment) has never seemed to affect the ships

I did a tensile strength calc. for your 6mm bolt. As you say, with regular strength steel it will likely fail at 45deg heel (need 308kg but have only 296kg in a 6mm bolt of regular steel). But high strength steel is twice as strong, and would do the job. Or, you could redesign finkeel support so that it used 2 regular strength bolts per side, with some factor of safety.

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Tensile strength of regular steel = 60,000psi, or 42kg/sq mm

Generally, one tries to design using factor of safety of 2, so 60ksi => 30ksi proof load, 42 => 21kg/sq mm
21kg/sq mm of steel x area of solid steel of bolt=design, or proof, strength of the bolt.

So, using 4, 6mm regular strength steel bolts per side of the finkeel should work for a "proper engineering safety" support of the 45deg heel. If you can get 4 of them per side into your existing finkeel design, no stays or brackets would be needed for the 45 deg heel.
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My calc. was rough, with estimates of bolt diameter less thread depth (I guessed 50% loss of diameter due to threads). So, you'd want to calculate strength based on the true, solid steel diameter of your bolt.

Incidently, people often wonder if the bolt threads will strip before the bolt breaks while under tension. With modern designed bolts, that can't happen; the bolt will break before it pulls out of the threads. Of course, you can strip threads with a wrench, but even then, often failure mode is the bolt twists apart outside the threads. There is so much surface area, within the threads, supporting the load, that the shaft of the bolt usually fails first.

Hope this helps.

Hey Lucc,
what´s the actual diameter of your keel?
(I mean the scale keel of the Santissima Trinidad, not the keel extension)

I have my 14 kg keel with two 12mm bolts.
Just trying to help you find a working solution.

Thanks guys to think.

There was also a second possibility, which is close to disable.

2 stainless steel wire rods 10M in a tube of inox12/10 would already give much better values​​.

Problem was that the brass tubes of 8mm in the keel of 7cm high and is glued with epoxy got away.

Today, in hope of victory, started it and it worked.

pictures will follow later.

language is dutch



now there's 13.92 kg on each stainless wire rod, this is exaptabel.

I know nothing about boats or scratch building but I'm blown away by all the beautiful work you've done. Makes me want to reread the Patrick O'Brian series. Keep up the great work and good luck.

thank you Planeur.

Progress.

I'm going to copy the dutch item here, it's to difficult to explain this (for me) in Englisch.

The photo's are clear.


René (Isola2) helpd me with de calculation and program Delftship



place off the leadbomb calculated

De bedoeling is dat het er als op volgende prtscr gaat uitzien



Afmeting kiel 300 X 300 X 18 mm, de maten van je draadstangen zoals op je tekening deze blijven dus behouden



Bovenaanzicht van kiel en flens , flens aan je kiel lassen



Perspectief kiel op zijn kop

Daarna kwam de berekening van René, welke krachten er op mijn 6mm draadstangentjes kwamen te staan.

Rod's to weak ,are going to bend


calc +solution

author=ISOLA2 link=action=profile;u=10 date=1370072489]
Heb alles nog eens nagerekend, bekijk deze tekening eens. Berekening bij 45) helling

Bij een helling van 90 ° komt er een trekkracht van 12 X 330/9 = 440 kg op de rand van je houten kiel en
220 kg trekkracht op iedere draadstang. Kan je constructie binnen in de boot dit aan ?
De trekkracht op de draadstang is geen probleem, maar 440 kg druk op de rand van je houten kiel wel, hout kan haaks op de vezel maar weinig druk verdragen .
Om dit probleem op te vangen gaan we de flens vergroten en de kiel met 2 hardhouten (met epoxy lijmen) latjes links en rechts van je kiel verbreden tot 50 mm. De krachten zien er dan heel wat gunstiger uit.
12 X 330/25 = 158,4 kg / 2 = 79,2 kg per draadstang. Bij 45° 79,2 X 0,7 = 55,44 kg

Nog een vraagje, kan je er aan de binnenzijde nog aan om naast die buizen dwars over de romp een stuk extra triplex te lijmen tot aan de bovenkant van de buizen?

De buitenkant dat kan het beste met 2 klossen L/R van de kiel tussen romp en flens zie prtscr

De klossen



Bulb, kiel met flens



Gemonteerd

De krachten op mijn kiel waren nog steeds te groot volgens mijn goesting.

Best and first solution off René.

DE messingbuizen eruit halen en vervangen door inoxbuizen van 12/10.

Hierdoor konden er 2 inox draadstangen in van M10.

Deze gingen niet meer doorbuigen waardoor de krachten op de kiel totaal anders werden.

[quote author=ISOLA2 link=action=profile;u=10 date=1370291044]
De krachtverdeling met 2 stangen van 10 mm in buis 10/12

13.92 kg per rod is a better solution.

the operation yesterday. on my back on the ground.

Originally Posted by disabled

Hey Lucc,
what´s the actual diameter of your keel?
(I mean the scale keel of the Santissima Trinidad, not the keel extension)

I have my 14 kg keel with two 12mm bolts.
Just trying to help you find a working solution.

thx disabled

2 questions:

what is the distance between keel and ship.

and the thickness off the keel from the ship ??

Don't forget to make sure she won't be too deep for where you're sailing her.

Lucc, is there any chance of you posting the DELFTship model on this forum? I know there are a couple other DELFTship models floating around here, and I am currently working on one for the Russian sloop Mirny.

Originally Posted by kotori87

Lucc, is there any chance of you posting the DELFTship model on this forum? I know there are a couple other DELFTship models floating around here, and I am currently working on one for the Russian sloop Mirny.

I didn't do this. A member of an other forum makes dies models.

He's very good in this,

I can ask this , but what do you need exact?

how does one download delftship for win7....?.....i just get a lot of other sites...

the link and you have to make an account

http://www.delftship.net/

got it...thanks....couldn't figure out the spam check thing...if i had trouble figuring out the registration, you can imagine the fun i'll have with the program itself