Dry exhaust vented through mast

[mmd]

Hello, all.

A client has asked me to investigate the posibility of venting the main engine exhaust through the mizzen mast of a trawler-to-sailing ship conversion. I have seen examples of this (the "Star Clipper" is one) but only from a distance, so I have not seen the structure and fittings of this arrangement. Does anyone here have information, photos, blueprints, etc. that I could look at? A name or link to a person, shipyard, or NA/ME office with experience in this would be of great help, too.

Thanks in advance for any assistance you can give me.

Best regards,

Michael A. Mason
Mason Marine Designs Inc.
mmason@tallships.ca

[JORGE LANG]

Is there a specific reason why your client wants to have the exhaust going through the mast? One issue of concern would be insulation of the exhaust pipe. Is there enough room in the diameter of the mast to accommodate the insulation?

[mmd]

Hello, Jorge. Thank you for your prompt reply.

The client wishes to have the exhaust thru the mast to keep soot and odour above the passenger lounging area on the aft bridge deck and to keep the mizzen sail clean. The mast diameter has not been determined as yet, pending engineering calculations and exhaust requirements. I understand the need for thermal insulation, among other concerns, and am attempting to gather as much data as possible on the design requirements before I commit to preliminary design.

I know of DeAngelo Marine from a previous project (sorry, the client at the time decided against using your services) and have high regard for your products. May I contact you directly to further discuss the current project?

Just read your enquiry. If you haven't completed the project yet I can maybe help. You do not need to insulate the mast. Instead you can use a conventional wet system with a water separator. The water exits the hull in the normal way and the separated cool exhaust can exit the mast. I used this system on a 140' luxury yacht and it works fine.

[mmd]

Thanks for your reply. The refit is complete and the owners opted to stay with the existing conventional dry exhaust system. Modifying the exhaust system was a bit of a pipe dream (pun intended) because they were trying to do a tremendous amount of work on a shoestring budget. I was obliged to investigate all possibilities on their part, but was doubtful that this was going to be on the work list.

[Raykenn]

Dear MMD,

In 1982 I was working in the caribbean on a 65 ft steel hull schooner that used this arrangement with good success. The mast was steel and was "boxed in" from the deck to approximately the 6 foot level. The box hid and protected the insulation and kept people away. Additional thermal insulation was installed below decks.

During the two years I saw the system in use there were no problems noted/ It did a good job of keeping the fumes and exhaust smoke away from the deck area.

Good luck with you project.

Best regards

R. Kennedy