Drive Showers slowing you down?
 

I have to ask this question. This weekend, I installed halo type drive showers on my boat. I have two pick-up ports that extend just below the cavitation plates on each drive. Here is my question: I lost 4 mph on GPS on my top end? Has this happened to anyone else? They said that this would not happen. Did I install these wrong? Any thoughts?

I put a Simrek halo on my 28' Powerquest and lost not .1 mph - there was no difference in the performance of the boat, other than my drive was cooler. Hard to believe that those little tubes could cause enough drag to notice, let alone cut 4 mph....

Depending how fast you are going some speed could be lost with the installation of a drive shower. 4 MPH seems like a lot, but I have heard the speedo pitot tube is worth 1 MPH on boats going over 80, so if the showers have 2 pick ups per drive I suppose it is possible to lose a couple MPH. Just get rid of the showers and dump the water out of your pressure control valves on your drive tops.

Hmmm, that's wild - I would've never thought it could have that sort of effect. Probably depends on hull, speed, etc etc.

Learn something new every day, I guess!

I'm like vette I have never heard of more than one mph which extra gas or the weather could cause ,but it does work better to use the dump water

Which speed was your GPS reporting ???

Over water or over ground ?? ;)

Maybe the original number was reported over ground with a 4 mph current :D

G

GPS readings are from a satellite and are not affected by current, the boat may be, but a GPS is as accurate as you'll get, land, sea, air!

I don't know........Could the props be cavitating at speed ?
i know the pickups on drive showers can cause cavitation at
slow speeds {coming on plane} if they are to deep......

:D :D :D

It depends on what you are measuring ;)

Tell us the scenario behing the GPS readings.

I loose 4 MPH on the GPS every time I turn around and drive up stream.

Here we go again! :D :D :D

:D

I just put Adjustable Halo's on my rig and as mentioned in the instructions if you run into cavitation raise the pick ups by 1/8" at a time untill it stops. Mine are adjustable with set screws I don't know if you can do that with other applications however.

I have not lose any speed but my rig only tops out at 68.

I installed a Simrek Halo(dual pick-up) shower on my boat as well. I noticed no loss in speed whatsoever.

No loss on my Velocity 280.

These things aren't that
hard to remove, and install.
Go out and run it, GPS it,
come back in, remove them,
run it again, GPS again.
That should eliminate all of
the "variables"

I'm with Bobby and Vette, too

jt

current won't affect gps readings. You should rethink that statement.

I was thinking the same thing......:D

Yep...:D:D:D

But for the record, GPS readings...Awww, nevermind.

yes it will, GPS measures your speed by FIXing on at least 3 sats
some Gps will work with 2, but will not be very accurate. The more the better , if the current is moving 4 mph and you drive with it , you will appear to be going faster , but in reality you are
not. for a accurate reading a Still lake will be your best move
and lock on many Sats.

Oh yes it will. Picture being on a treadmill running 4 mph, you gps will tell you that you are standing still.

:rolleyes: :rolleyes:
There should be an OSO rule that you cant argue an argument that has already be argued :crazy: :crazy:

I called OSO and got verbal confirmation that it was ok to make this argument. Now I find that because I didn't get it in writing, it will cost me 250 keystrokes and $35.:eureka:

:D
Cuda you should no better than that...always get it in writing.
A thousand lashes for you :chick:

What effect does synthetic oil have on GPS speeds? What brand of oil should I use on the GPS? Let's start all the arguments at the same time!

On a side note unrelated to this thread I shimmed my drive shower up so the hole for the pickup was flush with the plate, cured my blow out problem when coming on plane.

Your speed maybe faster on GPS if you are moving towards magnetic north, unless the drive showers are coated with Mobil 1 synthetic. Also, sometimes running in saltwater will affect the altitude of the sea level on lakes higher than 1000 feet.

I have terrible cavitation and I didn't mount them on it yet ! Also how can I mount my drive showers ? The directions don't make ANY sence ....

I have arnesons ........:crazy: :D :D

Hi Boddy, Whats this about the other way to get water on your bravo ? I don't quite follow that one . Also my friends 'cam' issue we spoke about is on the back burner for now ..... Thank you for your help though ! ;) JOE

C'MON....CIG1, YOU SERIOUS?
 

Depends on what you're measuring? What the hell does that mean? It's reading's off the sat system, it's doesn't matter if you are on ground, water or ait, YOUR SPEED IS YOUR SPEED!
BUT the boat can slowdown BECAUSE of the current BECAUSE it is moving slower! Now, if you are on a treadmill, running 4 mph, you ARE NOT moving...DUH!

I'm as serious as a heart attack .... as far as air goes, is ground speed and air speed the same? which one does the GPS measure? Both?.... NOT ;)


Then apply the same logic to water :)

Is your GPS speed the same going up river as it it going down river? NO But your "water speed" would be the same.

By the way ... I'll sell you a 100mph(GPS) Cafe Racer that runs on stock 496HOs ... how can you turn down a deal like that .... I'll let you seatrial it when I find a 30mph current to run in :D

2 Boats Leave Chicago
 

1 With a boat load of porn stars....1 with a boat load of Poodles...........Both going down current using BPS..."Butt Positioning Systems"..............

Yeah, but if you were going into the current........you would only have a 40 mile per hour boat using GPS. :D :D :D

Hey ... don't you start spoiling my boat sale ... it only runs down current .... I have the only one way 100 mph Cafe Racer :D

Actually Cig 1 if you relate your speed to a fixed point in space your going a lot faster than you think! Relatively speaking as Einstein would say.:D:D

F' it then .... I've got a 1000mph Cafe Racer that runs on stock 496HOs. :cool: Price just went up :D

Now your talking!

Re: C'MON....CIG1, YOU SERIOUS?
 

I think you're missing the point here. Now take the treadmill idea, extrapolate it to 70 mph in a boat with a 70 mph current, the gps would still say zero, but you would have 70 mph of water passing under your hull. In other words, the gps measures your COG (course over ground), not what speed you are moving through the water.

What if you're doing 4mph on a treadmill on a boat that is going 5 mph GPS up river with a 35 mph current? How fast is your actual ground speed?

I'm getting an ice-cream headache.