‘Pro:
1. Novelty - Glass enclosed promenades were just coming into being and it was the last word in modernity.
2. Protection - Perhaps more from wind than spray since by all accounts Olympic was a "dry" ship and
Lusitania a "wet" one, i.e., she threw a lot of spray.
3. Identity - Without this obvious modification, Olympic and Titanic would be almost identical.
4. Variety - 1st class passengers had the choice of a stroll under the stars (boat deck), sheltered (aft prom) or enclosed (forward prom). It is good salesmanship to give your customers a choice, even though the choice is meaningless.
5. Size - Ismay may have hoped that the enclosed promenade decks would be included in the ship's gross tonnage calculation, thus increasing the ship's size as a hedge against the Imperator class coming out the following year. (Gross tonnage survey laws, like tax laws, are very subjective. Owners of very large ships will occasionally petition for a re-survey hoping to INCREASE the size of their ship for publicity. Since port taxes are assessed on the basis of gross tonnage, the surveyors were probably pretty open minded, since you can never pay too much in taxes.)
Con:
1. Cost - White Star was being hit hard with the costs of new lifeboats, davits, bulkheads, etc., The cost of enclosing the promenade deck probably could not be justified.
2. Impairment of the value of Prom deck Cabins - Remember that the block of cabins forward on Prom deck looked out directly onto the walkway. When that walkway was open to the sea, those cabins all had a view and WS could charge more for it. After the side screen windows went up in Titanic, that view of the sea was for practical purposes eliminated and these expensive rooms looked into what was now practically a service hallway. WS might have gotten complaints in the matter.
3. Identity - The enclosed Promenade deck would now make Olympic look almost exactly like Titanic. This was certainly not desirable now. WS was so desperate to put the Titanic behind them that when the Britannic's specification book was drafted, citations referring to Olympic mention her by name but references to Titanic only specify her hull number... "Arranged as per 401"
Bill Sauder’