899 c hd si combo ???

[tmb]

ordering new boat Thursday and thinking about upgrading from the df that comes with the boat to a 899.my question is will this unit give a reading when on plane so you could use for navigation also.dont know a lot about these si units but have read they do not read well at high speeds.

[rnvinc]

Transducer installation position is the key factor for high speed depth readings...as the xducer must be in bubble free water to get constant depth readings...

This installation can be difficult with some hulls because boats tend to rise out of the water at higher on plane speeds...lifting the xducer completely out of the water...

Some install a shoot thru hull 2d xducer (XP 9 20) inside a fiberglass hull with a AS SIDB Y cable...

This allows the unit to get good 2d readings from the shoot thru hull xducer...and then mount the HDSI xducer higher on the transom to use at idle scanning speed...

Rickie

[Shellback]

I have a 16 foot deep V walk thru windshield boat, and my friend has a 17 foot bass boat. Both are powered by 60 HP motors and each runs a tad over 30 MPH top speed. Neither of us lost bottom with the compact SI transducer that is supplied with the 899. We now have 998 units with the larger transducer and still hold bottom at speed. Can't say what your results would be at higher top end speeds.

[skeetbum]

I get good reading with my 798 and a friend has trouble getting signal from his. As Barnacle Bill said, hull design and TD placement decides whether or not it will perform.

[crappies nightmare]

I had shoot thru 2d added to my 998 and it works great at 50mph

[cache22]

Even if you can't read bottom at speed, navigation should still work. From GPS, not transducer!

[Redge]

I also use a shoot thru the hull, Skeeter boat, get good readings up to 50 ish. I just don't go any faster than that.

[rnvinc]

ordering new boat Thursday and thinking about upgrading from the df that comes with the boat to a 899.my question is will this unit give a reading when on plane so you could use for navigation also.dont know a lot about these si units but have read they do not read well at high speeds.

There are a few advantages to using a shoot thru the hull 2d xducer and the AS SIDB Y cable....

*Less finicky when installing the HDSI xducer...
*Mounting the HDSI xducer up higher on the transom to keep from knocking off that $270 HDSI xducer from underwater obstructions...

Rickie