1965 41 DCMY Refit

[DCMY #92]

The Soundown rep was also very concerned about the bilge blower hoses that come up into the space behind the saloon walls providing a "leak" path for engine room noise. We haven't opened up the sidewalls yet to determine exactly how the modifications will be made, but I expect we will build smaller insulated trunks to replace these hoses. We may have to relocate the bilge blower from behind the saloon wall to the engine room.

I suspect we will have to eliminate the existing bookcases in the saloon sidewalls to make room for the air trunks. This will mean replacing some sections of the walls with new mahogany plywood.

I am certain that we will have to relocate the saloon A/C evaporator from its current location next to the starboard side forward air intake. There is a sufficiently large space at the rear of the galley's starboard side lower cabinet (between the refrigerator and hull side). This space is difficult to use for storage due to its shape and distance from the cabinet door forward of the refrigerator so using it for the A/C won't be a big loss. Access to the evaporator will require sliding the refrigerator forward, but that should not be too difficult for occasional maintenance. I hope to leave the existing A/C controls, return grill/filter and discharge grill where they are now in the saloon sidewall and duct the air to/from the evaporator.

In the past I would have resisted disturbing the existing interior wood surfaces with such modifications. I'm not so concerned about that now since installing new matching mahogany plywood is not all that difficult or expensive. If we are lucky, we may be able to relocate the existing (and flawless) section of saloon wall that would be concealed behind the new built in couch to the location of one of the eliminated book cases. For years we have tolerated and covered as best we could various holes and hatches in the aft saloon wall where the PO had installed speakers, telephone jacks, etc. That's all history after this refit. The holes have been filled and new mahogany veneer fitted. While veneer is more difficult to fit and glue, we chose it rather than plywood to minimize increasing the aft wall's thickness.

[DCMY #92]

For those who don't know what is behind the saloon walls on older Hats here is a photo. This photo shows the forward engine intake vent on the port side. Aft of this is an identical vent. The starboard side is similar, but with the bilge blower mounted between the intake vents. The light colored ovals in the cabin sole are plugs installed in the original air vents into the engine room.

I have a photo of the new intake trunk is being installed over this forward port side vent today, but the file is too large to upload. Apparently photos from my phone can't be compressed enough to upload. I'll get a photo tomorrow with my camera that I can upload and post it.

[DCMY #92]

Sorry - forgot to upload the photo.

[DCMY #92]

I should have explained what you are seeing better for those who don't already know. The brown rectangular structure is the splash guard. The hole in the hull side is behind it. The air comes over the top of this guard then goes down through the oval holes in the cabin sole. When in place, the cabin sidewall is aligned with the white paint line on the sole.

As I suspected the saloon A/C evaporator will have to be relocated from the starboard sidewall. Fortunately there is a large enough space at the aft end of the galley that is of little value for storage.

Some of you may find value in the the following information supplied by the A/C tech. A 16,000 BTU Cruisair unit requires a minimum 144 square inch area for the return grill and duct. It should have a total discharge grill area of 70 square inches. The return air grill should be mounted as high as possible to avoid pulling in cold air settled on the floor. The discharge grill should be located as far as possible from the return grill, preferably aimed in a different direction to minimize recirculation.

[jmencel]

wow ... reading through this post I am really impressed with the love evident in our older hatts. When it comes time to refit what strikes me is the obvious thought you guys put into a project to do it right and making things "better than new" while customizing to suite your own needs. I guess if one starts with a strong foundation, perfection seems to make wonderful sense. I am totally impressed, and I can see this Hatt is going to be absolutely beautiful when her hull touched the water once again. Thanks for sharing !

[DCMY #92]

Here is a photo of one of the new port side air trunks. There will be another aft of the trunk in the photo. The trunks are fabricated from "bending birch" (a plywood that bends readily around a form but will hold the bend once restrained). The trunks will be resin coated inside and out, then glassed to the hull side and saloon sole. Inside these trunks new air holes will be cut in the saloon sole. Each truck will be covered with 2" thick 2 lb/sq ft mass loaded Soundown foam. 2"-2lb Soundown will also be installed below the saloon sole, on fore and aft engine room bulkheads and under hatches. This will require dropping wiring bundles, water tubing and dismounting/remounting various equipment. It will be a pain, but doable.

We have relocated the bilge blower from the starboard hull side to under the saloon sole. Fiberglass tubes to carry bilge blower air will be installed inside a singe 8 foot long air trunk on the starboard side. This eliminates the need for access openings in the trunk to service the blower and air hoses. Building a single long trunk eliminates the tedium of sound proofing the bilge blower air tubes since they will be enclosed inside the new trunk.

I'll post more photos as this work progresses.

[DCMY #92]

I have mentioned before the poor design of the cabin sole Hatteras employed in 1965 - and who knows how long after. I bring it up again to share an additional improvement we are making while we have access behind the lower saloon walls to install soundproofing. Attached is a rough sketch showing the original arrangement, the problem that can develop, a previous modification I made where I had access from below to do so, and the current additional modification.

IHatteras supported the cabin sole on a small knee glassed into the hull side. Unfortunately they didn't extend the joists under the sole to rest on this knee, but only the sole's plywood. If/when the boat nails used to secure the joists to the plywood pull out, the sole sags. I have had this happen in the saloon where furniture sits, in the forward head where the washer/dryer sits, in the galley where the refrigerator sits, and in the aft head where there is no unusual sole loading. The noticeable symptom when the saloon sole sagged was misalignment of the doors to the saloon side wall book cases. In the forward and aft head it was misalignment of the doors to the head. In the galley it was the refrigerator listing to one side.

In the case of the saloon, where I could get access from below to do so, I jacked the joist near the hull side back up into position and installed a piece of aluminum angle to extend the joist onto the knee by driving it in with a hammer and bolting it to the joist. In the forward head, galley and aft head I installed blocks and wedges between a stringer and the joist. In some cases this required cutting an access hole in the sole.

Since we now have access to the saloon sole adjacent to the hull side we are taking the opportunity to through bolt the plywood to the joist. Hopefully this will prevent sagging at joists where I didn't have access to install the aluminum joist extension.

I hope these tricks will be of use to others with sagging cabin soles.

[DCMY #92]

Here is a photo of the new air holes into the engine room. The holes were relocated as close to the hull side as possible so the new trunk and its sound insulation would fit in the space behind the saloon wall.

[DCMY #92]

Here's an update on the saloon sound control work. Attached is a photo of the 6" fiberglass tubes that now carry engine room blower air. The blower has been relocated from the hull side to the engine room. These tubes will be contained within the new air trunks so they won't complicate installing the Soundown material.

The other photo is the completed air trunks on the port side. There is enough room to install some drawers in the port side saloon wall above the air trunks. After we get the built in couch and new saloon wall installed, we will decide if drawers will look OK. If so, it will help compensate for having to eliminate the in-wall book cases to make room for the trunks. Removing the drawers would give access to hose clamps, cleat through bolts, etc behind the wall.

We have decided to replace the original side deck scupper hoses located aft of the new trunks with new hose to avoid the need to do so later. Same for the potable water fill hose forward of the port side trunks. All of these hoses will be wrapped in Soundown also.

If the installation of Sundown on the underside of the saloon sole goes as well as I think it will (i.e, there are no gaps or areas we can't access for complete coverage) I don't think we will gain enough by installing a second layer of Soundown above the saloon sole to justify the additional weight. I hope this is the case. It pains me to add the roughly 550 pounds for the air trunk and engine room Soundown, let alone another several hundred pounds for the second layer. If I'm really lucky, I can eliminate the gen-set sound shield, loose more weight and improve maintenance access to the gen-set.

[DCMY #92]

Another update: Here is a photo of the new port side engine hatch with the 2"x2lb/sq ft Soundown installed. The hatches will be double gaskets (not yet installed) around the edges. The other photo is the new L-shaped couch sitting in position. The large holes in the couch are for access to storage behind and under the couch. You can also see the bottom of the open new center hatch.

Now that the hatches have the Soundown on them we know how heavy they feel when opening and closing them. It turns out that they are not too heavy for one person to open and close with no counter balance assistance from support struts. All hatches will get supports of some kind that hold them in the vertical position when open. We have not yet decided between gas struts, bending spring supports, electric linear drives, or some other method.

-My concern with gas struts is that they will leak down and get weak over time becoming an expensive maintenance issue (or safety issue if ignored).
-My concern with springs is how to bend both the spring on the left and the spring on the right at the same time so the hatch can be lowered by one person. Maybe we can rig a T-shapped tool to collapse the springs simultaneously?
-My concern with electric drives is their size.

Any ideas, experiences, or comments about support methods for these hinged hatches are welcome.