LA4 GEAR UP LNDG. PLT ATTRIBUTES INCIDENT TO TFC DISTR AND LACK OF GEAR WARNING SYS.

Narrative

I WAS ON BASE LEG TO FINAL WHEN THE SECOND ACFT CALLED ON THE RADIO ANNOUNCING THEIR POS ON A PRACTICE VOR APCH. THE APCH WAS TO RWY 23 AND THE RWY IN USE WAS RWY 5. I CALLED THE ACFT TO VERIFY THAT THEY HAD ME IN SIGHT ON FINAL. AFTER THE SHORT EXCHANGE ON THE RADIO; THEY CONTINUED TO FLY THE MISSED APCH AND I CONTINUED THE SHORT FINAL APCH TO A GEAR-UP LNDG. CONTRIBUTING FACTORS: 1) THE LAKE ACFT DOES NOT HAVE A GEAR WARNING SYS. 2) THE RADIO CONVERSATION AND LOOKING FOR THE TFC APCHING THE OPPOSITE END OF THE RWY; INTERRUPTED MY APCH CHK SEQUENCE. 3) COCKPIT LIGHTING IN THE LAKE AROUND THE FLAP AND GEAR CTL IS MARGINAL. CORRECTIVE ACTIONS: 1) INSTALL AN AFTER MARKET GEAR WARNING SYS. 2) IMPROVE INTERIOR LIGHTING IN ACFT. HUMAN PERFORMANCE CONSIDERATIONS: 1) I SHOULD HAVE EXTENDED MY APCH PATTERN OR MADE A GAR UNTIL CONFLICT WITH TFC WAS RESOLVED. THIS WOULD HAVE GIVEN ME MORE TIME TO REVIEW MY CHKLIST. 2) THIS WAS A 'NIGHT' LNDG CURRENCY FLT FOR THIS ACFT. THE ENG IS ON TOP OF THE FUSELAGE AND THE FUSELAGE HAS A BOAT TYPE KEEL; THEREFORE; MINOR SKIN DAMAGE WAS THE RESULT OF THE GEAR-UP MISHAP.