How fast can a Top Hat go?

[storm petrel]

Hi All,

Interesting dilemma! After cleaning Storm Petrel's bum and fitting a folding propeller, her top speed has increased significantly. At sea with a stiff breeze on a broad reach she now regularly seems to be trying to push over the hull speed - my GPS is recording 6-7 knots for extended periods(sometimes higher with wave help). This is great, except the bow runs up onto her own bow wave and when heeled this lowers her aft so much that and she starts to get a little water coming back into the cockpit through the drain holes around the insert that fills the outboard well. Nothing else has been changed on the boat and she is still as dry below as ever so as far as I know exceeding the hull speed is the only possible cause(I should mention that it only happens when she is travelling at over 6 knots). Prior to the folding prop being fitted I only got water back through the drain holes in the cockpit rarely and it was generally in pretty extreme conditions or due to having too many 'guests' in the cockpit when heeled.

I can live with a bit of water in the cockpit for the speed gain, but I thought it was interesting and wondered if anyone else had noticed this on other Mk11s or other Mks? (Note that my boat may be a little lower aft than others because she has an old 135kg Yanmar diesel)

Cheers,
Mark

[Phillip]

Oh Mark!

You haven't been reading my blog, have you!

[See http://www.sailblogs.com/member/seaka/ post date 04/06/2011]

Now, if I am casual about it, I can get 6 to 7 knots without trying.

If I power up in the right conditions, Seaka will clip along at an easy 7 - 9 Knots!

BUT if I get a bit crazy, as I have done,

SEAKA, a MARK 1, can do 11 plus knots!

Now, and I am sure Bear will agree with me, but for you to do that, you will have to get a MARK 1



Phillip.

[surrealbass]

Ha!! sorry but that pales next to a mark 0 (and a bit)!!! I actually had 16.8Kn out of joylee on my way home in a storm a few years back - even used to have the gps dump to back it up once, but not anymore- something about not backing up hard drives.... another story!

as for what happens at that sort of speed, we were wedged between the wave in front and the wave we were on and both were pretty much level with the gun'l the only water that came on green was a rogue that nailed my mate on the tiller fair in the back of the head while I was down below looking up. was quite hilarious. was on a dead run in about 45 knots according to the met. the weight may be about the same as I had the old arona beneath the cockpit then- although construction of the boat is vastly different to yours the all up weight is about the same. the good old tophat can still punch above her weight I reckon

not wishing to upset Bear and Philip- the Mark one is beautiful..... but the earlier ones are even more beautifullerer.. and the original IS the best

[storm petrel]

I think you misunderstood the question gentlemen! Perhaps I chose the wrong name for the thread. My intention was not to question your manhood or the speed of your craft. I was not talking about strong winds, sailing with a kite, 5 minute bursts, wave assistance, gale force winds, current assistance or anything of the sort. In fact I was not talking about MAXIMUM speed at all. Nor did I intend to implying Storm Petrel was particularly fast, just that she is faster than she had been! I do not think any Top Hat is particularly fast and Mk11's being a little heavier, definitely sit a bit lower in the water and are a bit stiffer and slower than the Mk1s - or Mk0's probably - (different strokes for different folks and all that).

I have no doubt that with a tail wind the boat would have less heel and the torque caused by the wind pressure on the sails would lift the cockpit high enough to avoid the problem. I am sure we have all sailed in yachts with overpowered kites and seen the bow inches from the water as the boat overtakes its own wave and watched in amazement as the tiller becomes useless and the kite trimmer takes over the steering of the boat. I am too old for that sort of excitement now days.....

My question was about water back-flowing into the cockpit from the drains when exceeding the hull speed by about knot, while on a reach or beating in a moderate (15-18 knot) breeze in a seaway with a few bods in the cockpit. It seems to me that my question remains unanswered.

Cheers,
Mark

[bearmcnally]

Guys I had Egret II doing 100 km/h on the F3 ? so anything is possible with a Mk1

Bear

[storm petrel]

Heck, forget to mention 'being towed' was also not part of my original question. That is impressive though Bear, 100km per hr and not a sail or even a 'bear' pole up. Still it looks like she is going a few km per hr short of the hull speed through ground level air. Mind you, I doubt that even a Mk0 has broken the sound barrier.

[bearmcnally]

Ha Mark ,
You must realize by now you must keep your questions simple ,so you get a simple answer ? Maybe that's the problem ? we might be simple !
"Now what was the question ?"

Bear

[bearmcnally]

Mark

That is interesting as I haven't had that problem as such .Yet since I put that D7 BMW (Beintrouble) in the boat she floats higher in the bum but will still push water up the rudder tube when she gets over 6 kts .The drains aren't a problem as mine are crossed over ,port to starboard /starboard to port .I don't know whether having that extra 500 lbs in Egret II 's keel would make any difference in the situation you mention , but it might ? When I was towed by the Coast Guard done the Swansea channel at 8 knts plus she did suck water through the drain in the transom and up the rudder tube ,but not up drains.

[storm petrel]

Thanks Bear, at least you figured out what the question was! My cockpit drains from the rear centre through thee or four 2 inch holes drilled at the base of the timber outboard mounting plate. The water that drains out passes around the outside of the GPR blank that fits into the outboard well. I do not have piped drains in Storm Petrel, but if I did I would make sure they were 'crossed over' also.

Seems the Mk0 and Mk1 do not have any problem with water coming back in, so I probably need to hear from other Mk11 and Mk111 owners...

[Shaun]

Mark, I reckon its the couple of extra bodies in the cockpit, look at weight distribution of gear (& crew ), or put Jacko on a diet
Never had any water coming in via rudder stock, outboard well drain or other in my Mk3's,

cheers