furuno thru hull 600w or 1kw

[skipalong]

thanks guys it helps now as i am getting an aluminium hull i will be going the 600w for the metal reacting purposes.

thanks heaps justin

[gofishin]

Hi skip,
Maybe as important to sounder power is the type of T/D and where it is located in the hull. Normally there are limitations to available locations, and these may be affected by lifting strakes, keel planks, prop noise etc.

From memory attenuation thru glass is around 4dB, thru ally is double that, and steel more than double again (not that many on here would need to worry about steel). Doesn’t sound a lot, but it’s obviously better to go thru hull if you can. 200kHz signals are attenuated more in water than 50kHz (why 50 goes deeper), but 50kHz signals are a lot more affected by air bubbles/turbulent boundary layers on the hull. A good T/D selection & location for an ‘at rest’ hull is not necessarily the same at speed – especially when keel planks & lifting strakes are involved.

I would have loved a 1kW, as they do provide better readings/resolution all thru the water column (thanks to all those extra crystals as well as power), but was limited to 600W at the time - type & placement as suggested by the experts who know my hull. However, I can say I am very pleasantly surprised by the readings on the 585 at all speeds.

Select the type & placement of your 600W wisely (with help if needed) & it will serve you well.
cheers