In 1931 the Royal Mail Case resulted in the jailing of Lord Kylsant, and in 1932 the company was reconstituted as a new body, Royal Mail Lines, chaired by Lord Essendon.
He claimed that German, Italian and French competitors were running ships to South America at 22 knots (41 km/h), giving a passage about five days quicker than RMSP.
The new RML company immediately considered how to raise the speed of Asturias and Alcantara.
Essendon concluded that foreign competitors were losing money at 22 knots, but a range of options to raise the speed of Asturias and Alcantara to 19 to 22 knots (35 to 41 km/h) should be evaluated.
Essendon also proposed inviting foreign competitors to agree on a 19-knot speed limit on the South American route, so that all companies could economise on fuel and attempt to cover their costs.

At that time marine diesel power was at a relatively early stage of development, and RML considered it unable to increase the two ships' speed to the required level.
Lord Essendon therefore recommended steam turbines, and two options for the drive system: either conventional reduction gearing, or the newer turbo-electric transmission that had been pioneered in the USA and successfully applied to US, UK and French ocean liners.
Whichever transmission was chosen, the cost of re-engining Asturias and Alcantara was estimated at about £500,000.
Lord Essendon also urged RML directors to order a third ship of similar speed to share the route with Asturias and Alcantara.

Given the Great Depression at the time, the RML board rejected the idea of a new ship.
At first it was prepared to have only one ship re-engined, and proposed reassigning the other to cruising to replace the ageing A-series liner Atlantis.
However, in May 1933 the board consented to have both Asturias and Alcantara re-engined, and at the same time to lengthen their bows by 10 feet (3 m) and improve some of the accommodation.
RML awarded the work to Harland and Wolff, but with a condition in the contract that the ships must achieve at least 18 ³⁄₄ knots (34.7 km/h), and a graduated penalty clause in case the actual speed increase should fall short of that figure.
In the same year, Lord Essendon succeeded in getting RML's competitors to accept a 19-knot speed limit on the South American route.

Harland and Wolff fitted each ship with three water tube boilers supplying superheated steam at 435 lbf/in² to a set of six turbines that drove her twin propeller shafts by single reduction gearing.
The National Physical Laboratory helped the shipyard to design new aerofoil-section manganese bronze three-bladed propellers, and the rudders were also streamlined.
The new machinery succeeded in increasing each ship's nominal horsepower by 25% and increased their speed to about 19 knots (35 km/h).

Each ships had two funnels, of which the forward one was a dummy.
As built the funnels were low, which was a fashion for some 1920s and '30s motor ships.
When the ships were re-engined in 1934 each funnel was increased in height.

The improvement to passenger accommodation was on "C" deck.
A large number of small cabins was replaced with a smaller number of more spacious ones.
As revised, "C" deck on each ship had 61 cabins, 47 of which were given en suite bathrooms.

Asturias was converted first, going to Belfast in May 1934 and returning to service in October.
Only after Asturias had successfully completed a voyage from Southampton to Rio de Janeiro and back did RMS send Alcantara to Harland and Wolff at Belfast in November.
She returned to service in May 1935.
In 1931 the Royal Mail Case resulted in the jailing of Lord Kylsant, and in 1932 the company was reconstituted as a new body, Royal Mail Lines, chaired by Lord Essendon. He claimed that German, Italian and French competitors were running ships to South America at 22 knots (41 km/h), giving a passage about five days quicker than RMSP. The new RML company immediately considered how to raise the speed of Asturias and Alcantara. Essendon concluded that foreign competitors were losing money at 22 knots, but a range of options to raise the speed of Asturias and Alcantara to 19 to 22 knots (35 to 41 km/h) should be evaluated. Essendon also proposed inviting foreign competitors to agree on a 19-knot speed limit on the South American route, so that all companies could economise on fuel and attempt to cover their costs.
At that time marine diesel power was at a relatively early stage of development, and RML considered it unable to increase the two ships' speed to the required level. Lord Essendon therefore recommended steam turbines, and two options for the drive system: either conventional reduction gearing, or the newer turbo-electric transmission that had been pioneered in the USA and successfully applied to US, UK and French ocean liners. Whichever transmission was chosen, the cost of re-engining Asturias and Alcantara was estimated at about £500,000. Lord Essendon also urged RML directors to order a third ship of similar speed to share the route with Asturias and Alcantara.
Given the Great Depression at the time, the RML board rejected the idea of a new ship. At first it was prepared to have only one ship re-engined, and proposed reassigning the other to cruising to replace the ageing A-series liner Atlantis. However, in May 1933 the board consented to have both Asturias and Alcantara re-engined, and at the same time to lengthen their bows by 10 feet (3 m) and improve some of the accommodation. RML awarded the work to Harland and Wolff, but with a condition in the contract that the ships must achieve at least 18 ³⁄₄ knots (34.7 km/h), and a graduated penalty clause in case the actual speed increase should fall short of that figure. In the same year, Lord Essendon succeeded in getting RML's competitors to accept a 19-knot speed limit on the South American route.
Harland and Wolff fitted each ship with three water tube boilers supplying superheated steam at 435 lbf/in² to a set of six turbines that drove her twin propeller shafts by single reduction gearing. The National Physical Laboratory helped the shipyard to design new aerofoil-section manganese bronze three-bladed propellers, and the rudders were also streamlined. The new machinery succeeded in increasing each ship's nominal horsepower by 25% and increased their speed to about 19 knots (35 km/h).
Each ships had two funnels, of which the forward one was a dummy. As built the funnels were low, which was a fashion for some 1920s and '30s motor ships. When the ships were re-engined in 1934 each funnel was increased in height.
The improvement to passenger accommodation was on "C" deck. A large number of small cabins was replaced with a smaller number of more spacious ones. As revised, "C" deck on each ship had 61 cabins, 47 of which were given en suite bathrooms.
Asturias was converted first, going to Belfast in May 1934 and returning to service in October. Only after Asturias had successfully completed a voyage from Southampton to Rio de Janeiro and back did RMS send Alcantara to Harland and Wolff at Belfast in November. She returned to service in May 1935.
RMS Asturias (1925)