Can you hear ir? Your hull speed?

[Brian D]

In the thread about a trip to Catalina Is., and on the Trailerable Sailboats, there is a discussions about hull speed, I got to thinking about my boat's hull speed. While sailing in San Diego Bay, I became aware of my hull speed by the sound of the water rushing (if I can use that word) by. Also, off the coast I can also tell when I reach hull speed just by the sound of the water.

Do you also have that neat talent? If one can call it that?

 

[redhead78]

Brian, I think that is something you will pick up on your boat, I,ve been sailing mine a long time between myself and the PO, I got it from. My guages for the engine is a similar concept, I installed the new Kubota guage panel where original was, while at the helm behind my ankles. I thought about moving but, it fit so well where the frogs put it.You actually have to leave the helm, around to the front of cockpit by the companionway and bend way down to see the tach. But like you were saying about hull speed I have found I can tell almost exactly how many R's I am doing, from the pitch of the engine...only good thing is its out of the way...Red

 

[Bill Roosa]

Hunter 40.5
waves flat
gurgling at 3.5
stern hull to deck seam just above the water at 4.0
seam at the waterline with occasional "lapping" over 4.2
seam mostly underwater with occasional rises above the waterline at 4.9
seam fully underwater at 5.3 knots

 

[patrickfarley]

I know when I hit 3 knots because she starts to sing.(keel cable)

 

[redhead78]

My favorite, at about 15 kts breeze, on a reach, fairly quiet water, my boat is just perfect, the reason we go thru all the pain and expense on our boats...just cruising, hard to explain, you guys all know what I'm sayin..

 

[FourPoints]

I can clearly hear when I exceed hull speed (usually under spinnaker).

Additionally as the stern appears to squat down from the bow and stern wave rising up as I approach hull speed, the sugar scoop stern no longer has water flowing smooth aft from under it, and starts to wash up over the bottom of the stern scoop, and rises up towards the swim ladder. This is actually the main source of the sound.

 

[sailaway78]

My first

My very first sailboat was a swing keel Chrysler 22. I could tell from how the keel cable hummed, how I was doing.

 

[Ken Cross]

Our old Mac 26d had a shudder (daggerboard osculation) at hull speed. You felt it more than heard it. Our SanJuan 28 that we have now doesn't get to hull speed often, but the sound doesn't change a lot with a bone in her teeth.

 

[shemandr]

But can you tell your speed while in your berth?
It's amazing how in tune with the elements you can become and that is a great joy of sailing. Even asleep you can detect something has changed. When anchored there is a regular rhythm of wind coming in the port above my berth as the boat swings around on the anchor. If there isn't that breeze on time - I'm up to check things out.

 

[FourPoints]

Even asleep you can detect something has changed.

Very true... Ask Roger about that, when we wrapped the prop about 2am as we were entering Ambrose channel in 20-25kts of wind, how long it took me to get on deck.

 

[PaulK]

When we hit 12 or more knots it's simply too noisy, between the wind, and the water, and the guys whooping. Only done it a few times, but it IS fun!

 

[zeehag]

i used to be able to hear the hum of the tranny at 5 kts--then i added oil and it is quiet....
i have yet to achieve hull speed--is 7 kts--i have done 8.4 kts, in 60+ kts of wind(chubasco), i have gotten 5-6 kts out of her in 15-20 kts winds--but i have yet to achieve 7 kts of boat speed....seems the pacific winds do not blow here much in winter. harbor winds are great, but the winds off zihuatenejo are only 5-10 kts.....

hull is thick and is difficult to differentiate the sounds of the hull through the water on a downhill run.....

 

[Anonymous 121765]

I Hear Ya Pal

Brian,

You're correct man. My C30 definitely has a sound I hear when hitting hull speed. Also, look at the mid beam area and watch how the flow of water dips like an inverted wave lower in this area. In addition, for me it feels like the boat rises abit. I tell my passengers the boat is sailing "lighter".....

CR

 

[redhead78]

Isn't it a great feeling, as we come up to speed in 15 -18 kts, the sheets tighten and groan, the boat seems to squat and dig into the water. On a starboard reach my boat will steer itself, port needs more correction, I'm guessing starbaord tacks are tuned better, just as a result of the location of tanks, batteries, gear ect...

 

[dscribner]

I can usually, tell by the sound, when I hit hull speed. It sounds like an 8HP motor. But . . . I do play the "I think we're going X knots" game. Good to know what you're speed sounds like if you haven't got a knot meter and you have to do a little DR to get back home, or stay off the rocks, or make it to the harbor in fog.

 

[TomY]

I can't say I know the sound of my boats hull speed, but I do enjoy and occasional hissing sound my boat makes while under sail in flat water and not too much wind. I think it is the sound at the waterline under the counter as it pulls off the hull?

 

[FourPoints]

This thread reminded me of the sound my 14' tunnel hull scow I sailed growing up made... When it would get up over 10 or so knots (pre-GPS, and it didn't have any instruments, so going by gut only), it would start to make a sucking sound and throw a rooster tail from the rudder.

Around 13-14kts when the windward hull was flying, the weather helm would get bad enough that the nearly the entire windward side of the rudder would be dry, even though the entire rudder was still "underwater". Talk about rushing water sound there!