Here is a commercially made towfish my by FirstResponseOutfitters.com. Cost with HDSI Transducer is $799. They say its built like a Tank!
For more information, contact:
FIRST RESPONSE OUTFITTERS
12435 FM 830
WILLIS TEXAS, 77318
Phone: 936-890-8500
Fax: 936-856-7839
E-mail:
CRISTIN@FIRSTRESPONSEOUTFITTERS.COM