10kn ! Can this Be True ?!

[otherthan]

was reading about someone racing a hinterhoeller 28, he claims to reaching 10kn or more...this boats hull speed is 6-7kn.

I dont know much about sailboats how is this possible?

[CDunc]

not unless he is planning or surfing or has one big engine.

[otherthan]

what is a full plane?

[CDunc]

when the boat goes up and over the bow wave like a ski boat does, the boat then is ridding on top of the water so to speak. It is possible on racing sailboats especially if they have flat sections.

[CDunc]

It doesnt look like its the type of racing boat I had in mind, I doubt he is making 10knots over water, possibly that is his speed over ground with a very strong current. HR-28 (HINTERHOELLER) Sailboat details on sailboatdata.com

[delmarrey]

Yeah man!


.

[ozskipper]

Yes its possible. The hull speed (Square root of W/L) you speak of is theoretical. Once a boat starts to plane or surf all that data goes out of the window. Thats how a 9ft sailboard can reach 20 knots-else, based on the theory, its max speed could only be 3knots

Having said all that, the design of the boat in question, does not appear to be a rocket ship. So the ten knots was most likely momentary or when surfing. But certainly do-able.

HR-28 (HINTERHOELLER) Sailboat details on sailboatdata.com

Cheers
Oz

[SabreKai]

Umm, HR-28 has the same LWL as the Grampian 26, about the same sail area and weighs about 400 lbs more. Gramps are known to be very fast boats and I've never seen nor heard of anyone ever getting one up past 7.8kts. No matter what point of sailing or what amount of sail area I had up, I personally never had either one of mine past 7.6 and that was for sure a momentary spike. You could see the log bouncing all over the place as we went along. 10kts? Maybe if you strapped a Saturn V to it. Otherwise, I'd have to see it to believe it.

Sabre

[savoir]

You would need waves of 10ft plus to give the boat a push along and then it might hold 10 knots for 3 seconds or so.

As for sailing to windward, it would be battling to hold 5.

[bigpuff]

it can be done,down wind,big following seas,kite straining ,rudder shaking,crew hollering,mum yelling and beleave me you no your doing the 10kts.(feels like 20)

[S/V Alchemy]

I have surfed at just over 10 knots downwind in a Newport 27 during racing. Conditions were similar to what Bigpuff describes.

I have "part surfed" my own 33 footer, but not to that extent. My hull speed is around 6.9 knots to judge from the waterline, but I have had in certain conditions 7.3-7.5 sustained for 60 seconds or more. My highest speed on a momentary surf was 8.2 knots on a broad reach in about 25 knots of wind right in front of the Toronto Islands...I got lucky with a passing front.

I've surfed faster on bigger boats, but I don't count that if I'm not at the helm.

The "feel" of surfing a sailboat is quite distinctive. It's reminiscent to me of the feeling you get just before an elevator stops, if that makes sense. There's a perceptible lift and the bow waves stop splashing and gurgling and start hissing as less hull impedes them.

Keep your moves very conservative on the helm and sheets. It's very easy to broach in this wondrous state, and the "control surfaces" actually in the water are lessened to a degree.

But it certainly is an exciting part of sailing.

[witchcraft]

A broaching boat when near another boat is a hazard. when going that fast one can easily become out of control. We certainly have sailed faster than our theoretical hull speed but one must have control, paying special attention to how much sail is up when downwind.
Of course our highest speed was with a huge assist from the current.
Fair winds

[Jim Quibell]

Originally Posted by SabreKai

Umm, HR-28 has the same LWL as the Grampian 26, about the same sail area and weighs about 400 lbs more. Gramps are known to be very fast boats and I've never seen nor heard of anyone ever getting one up past 7.8kts. No matter what point of sailing or what amount of sail area I had up, I personally never had either one of mine past 7.6 and that was for sure a momentary spike. You could see the log bouncing all over the place as we went along. 10kts? Maybe if you strapped a Saturn V to it. Otherwise, I'd have to see it to believe it.

Sabre

My nephew & I left Bronte at 6am on June 7th to sail direct to Cobourg. We arrived in Cobourg at 8:20pm that night. 79.9 nm, average speed 5.4 kts. max. speed 8.9 kts. Just off Port Darlington, we encountered winds of over 25 kts. and the waves kicked up something fierce. We reefed quickly and ended up doing some very high speed surfing down the waves. Too busy to notice the speed at the time, but our Garmin map gps showed a top speed of 8.9 kts. during the trip. I still have not deleted that top speed from the unit. I have no idea what the actual speed would have read on our knotmetre (paddlewheel) - too busy keeping the boat sailing well.

[Pete7]

Originally Posted by delmarrey

Yeah man!


.

Great photo, do you know anything about the conditions? was the yacht facing into the wind so that a huge wave has just gone under the hull, or is the yacht going down wind under main alone


Pete

[boatman61]

Ahh.. one of the many things I never think of about boats... aware of it but its back of my mind as a 'minor' thing...
But I'm well aware of the effects of exceeding it... running into La Coruna, Nth Spain from the West before a 40kt wind and big sea's with 2/3rds jib on a jammed furler 90% of my time was spent with about 6inches freeboard at the bow... I was to busy steering to switch on the GPS for SOG and had no log but I reckon she went well over 10kts on occasion... did the 30mile retreat in 3 1/2 hrs.
This was a Hurley 22.... one of those "Know your alive.." moments.
Pictures below so you can see how deep she was running... and yes.. I'm aware of the 'what if's'...