TOP HAT HULL

[surrealbass]

still have to agree with Bear on this one, a prepped mould as it is bolted together is a wonderfully"finished looking thing (so SHINY!!) and anybody i.e. reviewer not familiar with what they are seeing would be easily confused. any boat with any sort of tumblehome at all cannot be made with a one piece reuseable mould as it will just not "pop" when the time comes- seen a couple where a mate tried to get away with a simple mould and it turned into a tug of war!! so you prep it wwhile you can reach inside easy- bolt her together, finish her off and start glassing, unbolt the lot and hopefully things will spring apart!! the better the prep and mould making the less "flash" on the "seam". Very good of you to 'fess up Philip!! this could go on for ever, Maybe bear has a few more tophat mould photos... I have some but they are more of the fungal variety...

Chris the Tophat sailor who has almost forgotten what it's like...

[Troppo]

How can I sleep at night, I'm tossing and turning, "Was my Tophat one piece or two?"

[surrealbass]

What am I to think?.... mine has about 20,000pieces

and what is all this Marque stuff - I have a marque nothing??

lmao!

[SeaLady]

I am still waiting for mine to be in one piece and in one place.
Currently bits everywhere.

[bearmcnally]

WARNING : SNIFFING GELCOATS AND FIBERGLASS PRODUCTS CAN CAUSE ..,
Hey man ? Fancy pouring molten lead into a fibreglass hull ? Now maybe them blisters you'll have cut out of your hull might not been osmosis ? they might be heat blisters ? "The new layout appears to give even more cabin space " what in the .... hell was that person on ?


Now, the lead keel is poured into a mould which is normally buried in a sand pit to hold it steady .Some amateur builders placed the ingots in the hull and then poured a mixture of resin and sand around the ingots to hold them in place .



Thank god I own a Mk1 The prettiest of all the Top Hats , And always remember the original is the best .
Bear

[Phillip]

Trust you to notice that about the lead keel Bear!

Apparently only some of the very first Mk 1's had a solid lead keel [cast before placing onboard of course].

The next stage was to place lead ingots [of which I think I have an example] these were then encased in resin or concrete [which is yet to be confirmed]. Seaka was built in 1969 and has ingots in the ballast. I am sure of this, as I removed about 70kg of ingots from forward of the main bulkhead when I brought her. See below for why this was added.

The next stage was shot [of steel or lead is unknown] encased as above.

But by the time the moulds were sold to Form-It they were using the shot method.

Sometime after production of the Mk 2's started [or maybe even with the first couple of Mk 1's produced at Form-It] extra ballast of about 100kg was added to stiffen the Top Hat for the racing click! This also explains the reduction in water carrying capacity of the Mk 2 & 3's compared to a Mk 1.

The Mk 1's have 2,500lbs [or 1,135kg for you young lot] while the Mk 2 & 3's have 1,234kg.

As far as I know all ballast was in place when a new Top Hat left the factory floor, including the few that were sold as deck and hull separate. I can be corrected on this.

Of course the Shoal Draft had extra ballast to compensate for the loss of the extra 300mm righting action. Hence no water tank in the keel.

That's the lesson for tonight!

[bearmcnally]

Hi Phillip,
What you have said is correct , as that is what I have heard about the lead shot and ingots, We used 55lb ingots in Jilpanger and mixed sand and resin together and poured it around the ingots.My Egret II has a solid lead keel with another 500 lb on top which has made her very stiff !!The only disadvantage is she is slower than most Top Hats in light winds ,in fact most winds? . You wouldn't be surprised how many yachts have ingots glassed in their hulls as this was a common practice. I've seen concrete,scrape metal ,rail line and such used in some well known designs to save on costs by the do it yourself boat builders.You can still see the odd one sailing on Pittwater (well crabbing )

cheers Bear

[Dolphin]

G'Day Phillip,
I can also confirm that there are ingots of 50kg of lead in the bow of Felicite under the fore peak. There was a section that was cut and rescrewed. I opened it up to find the ingots were just laying there rolling around. I glassed them in. I think that was to trim the boat and it does as the MK3, as everyone knows by now, IS the fastest.
Bears boat isn't slower because it has more ballast it is slower because he has to fill in an Environmental Impact Statement (EIS) so he can get permission from Fisheries to move the reef!

[Phillip]

Gentlemen,

I did forget to mention that the extra lead in the bow was to lift the stern, as I was told.

I think this may have had something to do with the way Top Hats "sit down" at the stern when they get moving at around 5 knots plus. By maintaining a level boat there would be some considerable reduction in drag. Most Top Hatters will notice this by the way water comes into the cockpit via the cockpit drains when heeling. It’s not actually the heeling but the fact that the lower side of the cockpit floor has dropped below sea level as the drag of the stern causes the boat to "sit down'.

I use all sorts of crap in the bow cabin lockers plus 30m of chain and a large CQR anchor to do the same thing as the lead I removed! Even so, SEAKA will still "sit down' when she gets going, so I'm not really sure about the maths on this one!


My GOD Bear, is that 500lb [230kg for the young ones] of lead tied down????

If not, I would hate to be in EGET II's cabin in a 360 roll.


Oh, hang on, no Top Hat has done that yet, so you should be safe on the averages!!!

[Dolphin]

Phillip, just a word of warning, Putting heavy weights at the extremeties of the yacht causes a considerable increase in inertia, particularly in the bow, and slows the action of the boat in rising to a swell. Making the weigh out of something useful is best, I'd rather have 50kg of chain than 50kg of sand in the bow.
The other factor is moveable ballast, the crew. I remember a naval architect saying in small boats how useless it was to carefully design the waterline and shape of the craft, then place 500kg of bodies randomly all over the boat.
I also remember at the last Lake Mac sailaway having a large body of people in the cockpit and watching it fill with water.