Motor Tug No. 90 (YT-90).
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Class: MOTOR TUG NO. 86 (YT-86)
Design: Navy YT-86 (wood construction)
Displacement (tons): 54 displacement
Dimensions (feet): 65.0' x 16.2' x 6.2'
Armament: None
Complement: --
Speed (kts.): 9.4
Propulsion (HP): 150 shp
Machinery: one Union 4 cylinder, 4 cycle gasoline engine, single screw
Construction:
| YT | Name | Ord | Builder | Keel | Launch | Commiss. |
| 86 | Motor Tug No. 86 | 25 Apr 18 | Mare Is. NYd | -- | 1918 | 30 Nov 18 |
| 87 | Motor Tug No. 87 | 25 Apr 18 | Mare Is. NYd | -- | 1918 | 9 Nov 18 |
| 88 | Motor Tug No. 88 | 25 Apr 18 | Mare Is. NYd | -- | 1918 | 14 Dec 18 |
| 89 | Motor Tug No. 89 | 25 Apr 18 | Mare Is. NYd | -- | 1918 | 31 Jan 19 |
| 90 | Motor Tug No. 90 | 26 Jul 18 | NavSta. Pearl Harbor | -- | 19 Dec 18 | 15 Jan 19 |
| 91 | Motor Tug No. 91 | 26 Aug 18 | NavSta. Pearl Harbor | -- | 3 Mar 19 | 28 May 19 |
| 92 | Motor Tug No. 92 | 5 Nov 18 | Mare Is. NYd | -- | 20 Mar 19 | 24 Jul 19 |
| 93 | Motor Tug No. 93 | 5 Nov 18 | Mare Is. NYd | -- | 27 Mar 19 | 22 Jul 19 |
| 94 | Motor Tug No. 94 | 5 Nov 18 | Mare Is. NYd | -- | 2 Apr 19 | 26 Jul 19 |
| 95 | Motor Tug No. 95 | 5 Nov 18 | Mare Is. NYd | -- | 19 Apr 19 | 25 Sep 19 |
| 96 | Motor Tug No. 96 | 5 Nov 18 | Mare Is. NYd | -- | 10 Jul 19 | 25 Sep 19 |
| 97 | Motor Tug No. 97 | 5 Nov 18 | Mare Is. NYd | -- | 24 Jul 19 | 18 Aug 19 |
| 98 | Motor Tug No. 98 | 5 Nov 18 | Mare Is. NYd | -- | 9 Sep 19 | 9 Oct 19 |
| 99 | Motor Tug No. 99 | 5 Nov 18 | Mare Is. NYd | -- | 24 Sep 19 | 10 Nov 19 |
| 100 | Motor Tug No. 100 | 5 Nov 18 | Mare Is. NYd | -- | 1919 | 15 May 20 |
| 101 | Motor Tug No. 101 | 5 Nov 18 | Mare Is. NYd | -- | 1919 | 30 Aug 20 |
Disposition:
| YT | Name | Out of Serv. | Strike | Disposal | Fate | MA Sale |
| 86 | Motor Tug No. 86 | 15 Jan 46 | 7 Feb 46 | 16 Sep 46 | MC | -- |
| 87 | Motor Tug No. 87 | 9 Sep 46 | 21 Nov 46 | 26 Mar 47 | MC | --c |
| 88 | Motor Tug No. 88 | -- | 10 Jun 47 | 11 Jun 47 | MC | -- |
| 89 | Motor Tug No. 89 | 9 Sep 46 | 21 Nov 46 | 17 Jun 47 | MC | -- |
| 90 | Motor Tug No. 90 | -- | 16 May 44 | May 44 | BU | -- |
| 91 | Motor Tug No. 91 | -- | -- | 10 May 20 | Trf. | -- |
| 92 | Motor Tug No. 92 | -- | 21 Nov 33 | 22 Jun 34 | Sold | -- |
| 93 | Motor Tug No. 93 | -- | 11 Feb 37 | 7 Apr 37 | Sold | -- |
| 94 | Motor Tug No. 94 | 12 Sep 46 | 21 Nov 46 | 10 Apr 47 | MC | -- |
| 95 | Motor Tug No. 95 | 11 Sep 46 | 21 Nov 46 | 1 Apr 47 | MC | -- |
| 96 | Motor Tug No. 96 | 2 Oct 46 | 30 Dec 46 | 5 May 47 | MC | -- |
| 97 | Motor Tug No. 97 | -- | 14 Dec 38 | 16 Mar 39 | Sold | -- |
| 98 | Motor Tug No. 98 | 19 Feb 48 | 16 Jun 50 | 24 Jun 48 | MC/S | 24 Jun 48 |
| 99 | Motor Tug No. 99 | 24 May 46 | 19 Jun 46 | 18 Mar 47 | MC | -- |
| 100 | Motor Tug No. 100 | -- | 20 Oct 38 | 1 Feb 39 | Sold | -- |
| 101 | Motor Tug No. 101 | -- | 8 Mar 35 | 10 Jul 35 | Sold | -- |
Class Notes:
A precursor of this class was a 50-foot wood motor tug built at Mare Island in 1917. She was initially Special Motor Boat # 3187 (C-3187). Absent from the Ships Data Books through 1 July 1929 probably because she was considered a small boat, she was referred to as YT-118 in correspondence dated 2 August 1930, and had become YMT-14 by 1 July 1931 when the 1931 Ships Data Book was published. She was then at San Diego. YMT-14 became YTL-118 on 15 May 1944. Mare Island reportedly built three 50-foot motor tugs in 1917 but no record has been found of the other two.
The first four 65-foot motor tugs were ordered from the Mare Island Navy Yard on 25 April 1918 and assigned the numbers 86-89 on 6 June 1918. Photographs suggest they were enlarged versions of the 50-foot type. Two more were ordered from the Pearl Harbor Naval Station, and on 5 November 1918 another ten were ordered from Mare Island. Three were converted to ambulance boats before completion, for these see YH 1-3. YMT-2 and YMT-9, at Mare Island, had 150-hp diesel engines by 1931 and YMT 4, 8, and probably 10, also at Mare Island, had diesels by 1945. YMT-5, at Pearl Harbor, was re-engined with a large 240hp diesel engine but on 3 March 1944 a board recommended that the machinery and fittings be removed and the hull condemned. YMT-2 was refitted with a mast, boom, and gas driven deck winch during the 1930s and also had her pilot house moved to the forward end of her cabin, as was done in the many motor tugs built in the 1930s and 1940s. These also all had diesels.
Ship Notes:
| YT | Name | Notes |
| 86 | Motor Tug No. 86 | Trials 29 Nov 18. At San Diego 1931 and 1940. To YMT-1 c1930, to YTL-86 15 May 44. |
| 87 | Motor Tug No. 87 | Trials 7 Nov 18. At Mare Is. 1931 and 1940. To YMT-2 c1930, Had 150hp diesel engine by 1931. Refitted with mast, boom, and gas driven deck winch. To YTL-87 15 May 44. |
| 88 | Motor Tug No. 88 | At San Diego 1931 and 1940. 1940. To YMT-3 c1930, to YTL-88 15 May 44. |
| 89 | Motor Tug No. 89 | At Mare Is. 1931 and 1940. To YMT-4 c1930, to YTL-89 15 May 44. Had diesel engine by 1945. |
| 90 | Motor Tug No. 90 | At Pearl Harbor 1931 and 1940. To YMT-5 c1930. Had 240hp diesel engine by 1944. Machinery removed and hull scrapped May 44. |
| 91 | Motor Tug No. 91 | Built at Pearl Harbor. Transferred to the War Dept May 1920 (symbol YT-91 "not used"). |
| 92 | Motor Tug No. 92 | At Cavite 1931, named Tamaroa there. To YMT-6 c1930. Sold to Compania Maritima, Cavite, 1934. |
| 93 | Motor Tug No. 93 | At Pearl Harbor 1931. To YMT-7 c1930. Sold to Hawaiian Dredging Co, Honolulu, 1937. |
| 94 | Motor Tug No. 94 | At Mare Is. 1931 and 1940. To YMT-8 c1930, to YTL-94 15 May 44. Had diesel engine by 1945. |
| 95 | Motor Tug No. 95 | 98% compl. on 1 Oct 19. At Mare Is. 1931 and 1940. To YMT-9 c1930. Had 150hp diesel engine by 1931. To YTL-95 15 May 44. |
| 96 | Motor Tug No. 96 | At Mare Is. 1931 and 1940. To YMT-10 c1930, to YTL-96 15 May 44. Probably received a diesel engine in the 1940s. |
| 97 | Motor Tug No. 97 | Launched as Navy Ambulance Boat No. 1 at Mare Island 1919. To YH-1, 17 Jul 20 (symbol YT-97 "not used"). At San Francisco. |
| 98 | Motor Tug No. 98 | 98% compl. on 1 Oct 19. At Puget Sound NYd. 1931 and 1940. To YMT-11 c1930, to YTL-98 15 May 44. Out of service 26 Sep 46, stk. 30 Dec 46, in service 21 Feb 47 with fire pump, no crew. Sold by MC to Frank Sheffield, Nordland, Wash. |
| 99 | Motor Tug No. 99 | 90% compl. on 1 Oct 19. At San Diego 1931 and 1940. To YMT-12 c1930, to YTL-99 15 May 44. To WSA at San Diego. |
| 100 | Motor Tug No. 100 | Converted into Navy Ambulance Boat No. 2 at Mare Island 1919-20 (75% complete on 1 Oct 19). To YH-2, 17 Jul 20 (symbol YT-100 "not used"). In the 5th Naval District. |
| 101 | Motor Tug No. 101 | Converted into Navy Ambulance Boat No. 3 at Mare Island 1919-20 (60% complete on 1 Oct 19). To YH-3, 17 Jul 20 (symbol YT-101 "not used"). In the 5th Naval District. |
Page Notes:
YT 1918
Compiled: 25 Jan 2007 & 23 Nov 2025
© Stephen S. Roberts, 2002-2025