MacGregorSailors.com

Not me

Just everyone onboard the boat shooting the video....

G

Hey beene! if I go real fast WOT about 21 knots indicated GPS into the wind in choppy water the water splashes up in the air and blows into my face! It gets my sunglasses wet!! The only way I could get out of the spray was to stand in front of the wheelhouse!!

I wonder if the spray would go down if I let the ballast out??

BOAT wrote:I wonder if the spray would go down if I let the ballast out??

You get 21 kts with the ballast IN? Yikes!

Yeah, and that's INTO the wind! And I can get soaked if I don't get out of the way - the boat feels real good even in chop and I get a decent ride but the wind catches the spray and blows it in my face!! I think the fastest I ever got was 22.1 knots GPS downwind on smooth water (rare out here, smooth water that is) I can't wait to get out to a lake and dump the ballast and see what it can do early in the morning on glass.

I think the full ballast is what gives me the decent ride in chop.

I hear you

The only time I get wet at the helm is when I am xing waves at 45 deg in rough seas at higher speeds then I should be going for those conditions

So then I slow down

Ballast always in while the seas are rough, like in that video doing around 20kts

In calm seas, ballast always out when going fast, and no spray at helm

G

Okay, so that's the secret - ballast out no spray - that would make my wife happy (she HATES the motor - does not like being under power at all). I find it to be fun sometimes.

Yep, ballast out will have no spray unless you've got a beam wind, in which case it will spray water over the gunnels.

BOAT, you sure you're not reporting MPH? What prop are you using? My max speed with an empty Mac, no ballast, and WOT on an ETEC-60 with the 13.75x13 prop is 18.1 knots.

Matt

Huh, I dunno - I'll check it again this weekend - I get 16 knots at 3800 RPM - still have a LONG way to go from there and I have seen the GPS clock OVER 21KNOTS because sometimes I empty the ballast out in the ocean before I come into the harbor cuz they won't let me do that once I get into the harbor (I still don't know how those jet ski guys get away with it). I put it at full throttle and it just goes faster and faster and then there is no water left inside so i close the little hatch in the back. I will try to get a picture and I will recheck my GPS settings - I was using an Iphone - now I have the chartplotter - maybe that's what it is.

(Oh P.S. forgot to add - the prop is black, that's about all I know about props)

BOAT wrote:Huh, I dunno - I'll check it again this weekend - I get 16 knots at 3800 RPM - still have a LONG way to go from there and I have seen the GPS clock OVER 21KNOTS ...

GPS does not give you speed through the water...

That sounds like a Prop of Ship to me !!

j

Max Entropy wrote:

BOAT wrote:Huh, I dunno - I'll check it again this weekend - I get 16 knots at 3800 RPM - still have a LONG way to go from there and I have seen the GPS clock OVER 21KNOTS ...

GPS does not give you speed through the water...

Hey! That's right - I guess if there is a current or the tide is coming in or going out and I am near the harbor would it increase my GPS speed by 1/2 a knot or something? Is that it? Highlander says I can't go that fast so I must be doing something wrong - if the sea is calm this weekend I will try to get some movies and GPS data for you guys - last time wife and I went out 2 week ago the sells were 4 foot and real close together - those intervals kinda suck - not only was my tummy hurting but even my wife said she was queasy, and she never gets sick. Not a good sea for a motor boat - and I sure was not in the mood for looking at the viewfinder of a camcorder or iphone.

Highlander says I can't go that fast so I must be breaking the rules somehow or making a mistake - I will check it out.
All I can tell you is that the last time we had smooth seas was early in the morning and we were headed to Dana Point Harbor 25 miles north, but the wind was sort of dead too. So I set the throttle just to where the spray would not come into the boat - about 3800 RPM - I used the InavX program that mastreb turned me on to many months ago - great program - it said 16.5 I thought it was mph at the time too, but later that day at home I rechecked the setting on the InaxX program and it was set to KNOTS! Even I was surprised.

You guys have me wondering now that I must be wrong (again) so I will scope this out this weekend. I don't want to break the rules!

jsut a quick note, nowithstanding the speed through water vs speed over ground comments.

GPS is REALLY accurate in determination of heading , and speed, this is due ot trelitive measure of these 2 metrics, and the way that nearly all off the errors in GPS cancel out in this case.

kevinnem wrote: GPS is REALLY accurate in determination of heading...

Actually, as someone who is constantly fiddling with pointing and navigating lee shores, I should point this out.

Satellites are accurate in determination of track, not heading.

Heading is the direction the ship is pointing.
Track is the direction of actual movement.
(Confession: Had to Google these.)

It is most obvious when hove-to - track could be 90 degrees from heading. But it's still there if, like me, you're sometimes overpowered and poorly trimmed, resulting in excessive leeway. My boat's heading is due east to go round the point, but my track is ENE, and is going to take me onto the rocks.

If you're trying to get a good idea of your speed over water, you can cancel some variables outside the particular given conditions (waves, temperature, ballast, loading, prop etc) by taking the average of two GPS speed measurements made on reciprocal courses.

For best accuracy make your two power speed trials parallel to your best estimate of the resultant of the current and wind vectors. (ie. One with, and one against the wind and current, and not across them). The lower the boat speeds, the more this becomes important.

(I confess I did not Google this, but if you choose to, you just might end up right back here anyway! )

But you still need to be certain of your speed units. (BOAT )

Yeah, BE CERTAIN OF YOUR SPEED UNITS! And I think the handheld GPS might be bad cuz if you mover your hand forward or walk around the cockpit you add speed to the GPS??