Cessna P210 pilot reported an near midair collision (near midair collision) in the pattern at wst.

Attributes
ACN	1280076
Time
Date	201507
Local Time Of Day	1201-1800
Place
Locale Reference	WST.Airport
State Reference	RI
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Cessna 210 Centurion / Turbo Centurion 210C 210D
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Single Pilot Pilot Flying
Qualification	Flight Crew Private Flight Crew Instrument
Experience	Flight Crew Last 90 Days 60 Flight Crew Total 1500 Flight Crew Type 250
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 200 Vertical 50

Narrative:

We entered the pattern at wst after cancelling our IFR flight plan in good VMC. At that time; a pilot in a cessna cardinal departed runway 14 and announced that he had flown into a fog bank and would be flying eastbound. I made all usual callouts on the CTAF while approaching and entering the pattern at wst. These included 10 miles out; 5 miles out; intention to enter left crosswind; left crosswind entry; left downwind; left base and final. During our transit of the traffic pattern; the other pilot made similar callouts. He had decided to stay in the airport traffic pattern. We were ahead of him in the pattern. On short final (less than 0.5 miles from the runway threshold) and about 300 feet AGL; he flew underneath our aircraft. The separation was 200 feet or less.

Original NASA ASRS Text

Title: Cessna P210 pilot reported an NMAC (Near Midair Collision) in the pattern at WST.

Narrative: We entered the pattern at WST after cancelling our IFR flight plan in good VMC. At that time; a pilot in a Cessna Cardinal departed Runway 14 and announced that he had flown into a fog bank and would be flying eastbound. I made all usual callouts on the CTAF while approaching and entering the pattern at WST. These included 10 miles out; 5 miles out; intention to enter left crosswind; left crosswind entry; left downwind; left base and final. During our transit of the traffic pattern; the other pilot made similar callouts. He had decided to stay in the airport traffic pattern. We were ahead of him in the pattern. On short final (less than 0.5 miles from the runway threshold) and about 300 feet AGL; he flew underneath our aircraft. The separation was 200 feet or less.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.