Exterior Cabin Projects
The Bristol dorade boxes are molded into the cabin top and are a distinctive and identifying feature of Bristols. The trouble with the dorades is there is a gap between the molded cabin top and the bottom layer of glass that sandwiches the balsa core. That gap holds water, mold, mildew, dirt and God knows what else. Additionally, the box itself is not as large as I would like. SO as a part of this refit I will improve them by,
I will build a third dorade at the bow to ventilate the anchor locker.
If you ever wondered what the inside of your molded dorades looked like, take a look at these shots:
As I look at the dorades closer I discover this: The dorade boxes on the Bristol were made by molding the outer fiberglass skin in the shape of the box, eliminating the core between the out and inner skins and drilling a 3” hole in the inner skin into the cabin. The problem with this design is that the base of the box is below the outer surface of the outer skin, leaving a depression for water to collect and stand. To do it right, I will need to cut off all of the structure of the box, fill the depression with thickened epoxy and the build the box on top of the outer skin, like a proper dorade box should be.
After the four sides are cut to all the needed angles I clamp them in place with some plastic kitchen wrap under the corners. The plastic allows me to glue the sides clamped in place over the fiberglass sides of the dorade, and remove it when the epoxy dries. Then, I trimmed the sides with a Japanese saw, shaped it with my small belt sander and applied a first coat of epoxy thinned with acetone as a sealer. Before I can glue the dorade in place and add the top I need to recut the 3" vent holes in the cabin top. In preparation I glued in place two large pieces of 1/4" plywood.
After building both dorade fames to fit the existing fiberglass boxes, I finished a few small steps prior to fitting the tops in place.
I glued 1/4 plywood in place under each vent hole. The plywood will allow me to screw into place a 3" brass deck plate so I can seal the vents from inside the boat.
I recut the 3" hole using a 3-3/8" hole saw and sealed the edges of the fiberglass and plywood.
I glued a PVC stand pipe over the hole in each dorade box.
And I glued nylon screening to the top of the stand pipe. When Olin Stephens invented the dorade box he said firmly that screening was not necessary to keep out mosquitoes because they prevented light from showing outside and so the small bugs would not be attracted. I have glued screening to the three dorades because I wish to keep out larger pests, especially roaches.
Once the glue for the screens dried, I bored new drain holes in each of the fiberglass boxes and in each teak box. Two holes, on the aft face of each box, unlike what Bristol had built, allows the boxes to drain on either tack.
I prepared the top by first checking to see that each box was the same height and level to the leveled hull. They are close enough for my tastes. Then I turned over the port box and set it down into a thick fillet of thickened epoxy. Once it was aligned and clamped, I added 9 oz fiberglass tape around all the seams.
I spent a total of an hour sanding and shaping the top to the already shaped box of the starboard dorade. I used my Festool Rotex 150 which made amazing short and easy work of it. Some pictures follow.
And here is the port dorade shaped and ready to be mounted:
With two coats of epoxy on the two dorade boxes I test positioned the dorades and the dorade guards. The guards function as a brace for my butt when I am working at the mast, as a means of keeping flogging lines from wrapping around the dorade cowls, and as a guard to protect the cowls from the mainsheet, which runs down from the boom to a turning block on the mast step. The photo on the right shows the angle of the mainsheet with the boom extended. the sheet will run free without chaffing the starboard guard.
I installed temporarily the port dorade box with the cowl just to get an idea of how everything will look. Here are a few shots.
Here is one of the dorades after applying a second coat of System Three LPU clear gloss. It was applied over three coats of epoxy that I wet sanded to 320 grade. The S3 gloss is dry in this photo but hasn't yet been sanded.
The next step in improving the dorades is to mount the dorade guards. Previously I overbored all the 18 mounting holes. Now I positioned each guard back in place and carefully drilled the holes and taped each of them. I used my portable drill press rig as I always do to ensure that I drilled perpendicular to the surface of the cabin top. I used a 10-24 drill and tap set for them guard bases. Once all the mounting holes were tapped and dry fitted the guards. Then, I removed the guards, removed the bases and epoxied the bases to the guard tubes. These guards are a life saving feature of the improvements to my boat I will be trusting my life to them when I am offshore, so i will epoxy the tubes to the bases and then drill the bases and thru-bolt them as well.
Here both guards are mounted and glued and I'm waiting for everything to dry. Excuse all the clutter, After all the holes were drilled and tapped for the guards, as well as for all the other holes in the deck and cabin top, I bought some cheap screws at Home Depot and installed them to keep paint from running down into the holes.
Today, I began removing the mainsheet winch base on the port side of the cabin top. I will move the location of that winch aft and the winch base only interferes. I began sanding it down with a very aggressive belt sander, but my brother suggested using my Fein Multimaster with the flush cutting blade. Wow, does that thing cut. We had the base removed in a matter of minutes. I filled with thickened epoxy and will sand flush with the surrounding cabin. Next I over bored the screw holes when I will bolt the seahood to the cabin. The screws set the proper angle for screwing up into the seahood, which has already been overbored and filled with thickened epoxy, I poured thickened epoxy around the screws and when the mix kicked I backed out the screws, leaving the holes in the hardened glue. The holes will act as guides for my tap later--I will tap and attach the seahood with 1/4"x2" machine screws when everything is sanded and ready for paint.
Today I sprayed the companionway sliding hatch. The temperature was only in the mid 60's, but System Three paint seems to thrive in cold weather: it flowed very well. The base coats of Orcas White dried in about 20 minutes. It was thinned 25 percent with water. Previously I had sprayed the hatch with System Three WR-155 epoxy primer, and sanded lightly with 220 wet or dry.
After an hour of drying, I mixed 4 ounces of Gloss Clear crosslinked and sprayed it over the base coat. Again, the clear flowed very well and dried to the touch in an hour. Once the crosslinked coats have a week to dry and harden completely I will mount the sliding hatch and the seahood over it and begin building the dodger coaming down along each side of the doghouse.
While waiting for the companionway hatch to dry, I positioned and drill holes in the dog house for the stainless handrails. I then over bored each hole with a 3/4" spade bit thru the top layer of glass and the balsa core, but not cutting thru the bottom layer of fiberglass. Then I used a small screwdriver to dig balsa out wider than the bored hole.
The idea of the coaming is to provide a lip to screw snaps into to attach the bottom edge of a dodger and offer more protection from any spray or seas. The coaming will extend the aft edge of the seahood down each side of the cabin top to act as an attachment point for the dodger. Now that I have the seahood finished and the companionway hatch painted, they can be installed and accurate measurements taken for the coaming.
I began by marking the outline on the cabin: each side extends to port and starboard, then takes an accurate angle aft to intersect with the cabinsides aft of the rear portlight and in line with the forward cockpit coaming attachment. I used basswood and roughed out the shape on my trusty 12" band saw. It took three attempts before I finally got what I wanted. The basswood will be encapsulated in epoxy and i will add a layer or two of cloth to protect it.
Here is the same diagonal, cut to fit, temporarily screwed down and set in thickened epoxy. Here's the starboard side looking forward. When the epoxy is tack free, I'll add a layer of epoxy in microballons to begin fairing it.
Today I added the first of two layers of 6oz fiberglass to the coamings.When it hardened I trimmed off the scrap with a sharp knife, sanded the weave down smooth and added a second layer of cloth. I will sand that smooth and then paint the coamings with System Three epoxy primer. Then, all that is left is to drill the holes for the lines that will feed the rope clutches and the two winches.
Here are the coamings primed with the first coat of System Three WR-155 water-based epoxy primer.
Here I have bored the holes for the lines that run aft to sheet stoppers and the port winch: the windward traveller car haul, the outhaul and the mainsheet. I will add fairleads to the holes glued in thickened epoxy, then mount the sheet stoppers and the winch, a Lewmar two-speed #16.
Today I took off the measurements needed to order and have built stainless steel risers to support the midboom traveller. I am ordering these from Garhauer Marine. They build them to your custom specifications and Garhauer does beautiful work at a very reasonable price. Here are the measurements:
I ordered the traveller risers from Garhauer at the Strictly Sail Miami boat show yesterday. They should be here in a week.
The risers arrived this afternoon and I thought I would share them with you. These are the smaller of two models, designated UR1. They are extremely beefy. They are custom made to my measurements, from a full 1/4" stainless plate, with perfect welds and polished like chrome. They regularly cost $170.00 for the pair in the Garhauer catalog. I got them for $150.00 including shipping at the Miami Strictly Sail boat show. It took a little more than a month to get them.
Here is the basic shape from the side view. The base pivots to account for the curve of the cabin top. The horizontal plate is drilled for attaching the traveller. You can use Garhauer's traveller if you want to buy their traveller blocks. In my case, I already have a Harken Midrange traveller system so I will attach it to these risers.
Here's the underside of the unit. As perfectly finished in brushed stainless as the outside is polished. These are just gorgeous units. the workmanship in Garhauer's products is first rate and their prices are really amazing.
Here is a close up of on of the welds on the underside where they don't show. I expected less than perfect welds here--it doesn't matter right? Wrong. The welds are damn near perfect, as much as they are on the outside.
Next, I mocked up the traveller clamped to the risers to get an idea as to how close my measurements were. I took a straight piece of trim and clamped it to both risers. Then adjusted each riser so it was 7 inches in from the edge of the cabinside.
Since the cabin top is curved and the attachment base of the risers is flat I felt I needed a flat bearing surface. A midboom traveller must handle enormous forces: just think of a jibe in heavy weather and you begin to understand the strains it must absorb. I also believe midboom traveller risers are a common source of leaks into the cored cabin top--they usually are not mounted correctly and become a major source of leaks. So these risers will be mounted in a way that leaks are impossible. The outer cabin surface and the inside cabin surface will be flat so that the bearing surface of the mount and its associated backing plate will have a full flat surface to bear against. Furthermore, the bolt holes for the two riser brackets will be tapped to prevent any movement and any egress of water.
The outside riser base and the backing plate on the inside will be sandwiched between:
On the inside of the cabin I fashioned two 1/4" pieces of plywood and mounted them in thickened epoxy. I did not tighten down the temporary attachment screws so the pads would assume the curve of the cabin top; I purposely left them flat. They will act as a spacer for the Formica overhead cabin panels to lie against so that torque of the nuts on the backing plate do not stress or crack the Formica.
Then I overbored the mounting holes for the riser brackets and filled them with thickened epoxy. The mounting brackets for the Garhauer risers are drilled for 1/4" flathead bolts. Probably that is more than sufficient, but I drilled out the holes to the next size, 5/16". The flatheads will stand a little proud but I like the extra beef of the significantly larger bolts.
I ordered the new Harken traveller bar and received it today. It is very stout, uses a continuous running bolt head slot on the underside and comes with 8 stainless steel bolt head plates to fit into the slot. I ordered all stainless 316 hardware to attach the risers to the traveller. I used acorn nuts to create a finished look to the underside and used blue Lok-Tite to keep everything tight. In order to prevent any corrosion between the stainless risers and stainless mounting bolts and the aluminum traveller, I coated the bolt heads and the head plates that ride in the slot liberally with LanoCote and also the underside of the traveller that touches the risers.
To ensure I am drilling the mounting holes for the riser brackets square to the mounting pads, I use a portable drill press jig I bought at Home Depot. I mark the first hole, drill it, tap it, then mount the bracket and use it as the template for the second hole. Remove the bracket, drill and tap the second hole, remount the bracket for the third hole, etc.
After positioning the traveller in place, I used a 3/8" line to determine the exact positions for the traveller car control line turning blocks. The line must exit to the side of the traveller, down to a turning block to get the line parallel to the cabin top, and then another turning block to turn the line 90 degrees to lead thru the dodger coaming and eventually a winch. Here I have overboard the holes for one of the four turning blocks--two per side. The Garhauer turning blocks have the heads of rivets on the bottom so they do not sit flush to the cabin, so I am going to build a base of epoxy for the to sit on. Here you can see the rivets (I have wrapped the turning block in plastic wrap to keep it from sticking to the epoxy. Then I marked the perimeter of the holes so I can find them after the epoxy base is finished. Next, I mixed up a very thick batch of epoxy with 404 high density adhesive filler and buttered up the base of the turning block. I pressed the block down exactly where I wanted it so the epoxy spluged out. I used the sharp edge of the West stirring stick to clean up the excess epoxy and taped the turning block in place. Tomorrow I will removed the blocks and drill and tap the holes for fasteners.
Here are some pics of the custom-made trapezoid Bristol 29 hatch. If you are like me and dreamed of a weather proof, sea-proof hatch, this is it folks. I can not begin to say enough good things about Mariner's Hardware and Man Ship. take a look:
You can see the quality of the stainless (316), the welds and the polishing in this shot. Here is one of the hinges with my Canon S-50 perfectly reflected. The stainless looks like high quality chrome, only smoother and more reflective.
Today I prepared the raised forward hatch combing to received the new hatch. The Bristol's combing is curved and uses a curved fiberglass hatch that matches the crown of the cabin top. The crown needed to be taken out of the combing in order to fit the new hatch. I could have used a variety of tools--a grinder was suggested by my brother and a Sawsall comes readily to mind, but I wound up using my trusty belt sander. It took about and hour and was very controllable. I kept a level handy to act as a straight edge. I will have to fill the weather stripping groove and bull nose the outboard edges of the combing, but it will work just fine for the new hatch. Stay tuned for the hatch installation next weekend.
Today I continued modifying the forward hatch combing to receive the new hatch. After leveling it as best I could with the belt sander, I dry fitted the hatch and marked low spots. I puttied up the edges where I marked with thickened epoxy and sanded again. Then I took the belt sander to the sharp corners, rounding them and bullnosing the exterior edge of the combing. The sander cut through into some voids in the glass, which I later filled and faired with epoxy. Here is the hatch dry fitted. The combings are close to finished. They will received a coat of System Three epoxy primer. Then I will screw down the hatch but not bed it yet, as I want to remove it and the new ports when I paint the deck and cabin trunk.
I also ground flat the famous Bristol hatch lips where the yard bonded the cabin liner to the openings in the deck and cabin. It's always sort of an ugly, rough way to finish the joints and is common to most Bristol's. Since I am going to finish the inside of the hatch opening with cherry trim, it needs to be flat (like it should have been 40 years ago).
Today I did a number of small steps toward getting the hatch installed.
Overbored all the mounting holes for the hatch and filled with thickened epoxy.
Redrilled for the #12 x 1-1/2 in 316 stainless self tapping screws I ordered from McMaster.
Began dressing the inside vertical sides of the hatch coaming with cherry.
Here are a couple of pics:
this is the beginning of a description of mounting hardware on the cabin and deck. The first being a
1. Spinlock turning block
Here you can see that I have overbored for a new Spinlock turning block that will accept the mainsheet and the outhaul and route them back to the port side cabin winch. I cannot stress the importance of overborning a cored cabin top or deck. It is so easy there is no reason not to do it. The Spinlock takes a 1/4" bolt, so I overbored with a 5/8" hole. I will redrill it through now solid epoxy and it will never be stressed, or leak water into the balsa core. It is 50 year solution and one that you should always do.
Here's how to keep water out of your coring:
The bolts go through, washers and nuts with Lok-Tite added and the bolts cut off flush with the bottom of the nut. The whole assembly is less than 1/4" thick so it doesn't interfere with my overhead panels. Do this with every fastener thru your cabin and deck and you will never never have a problem with core saturation.
I am mounting a Spinlock triple clutch and a Lewmar #16 two speed winch on the port cabin top. The winch serves the mainsheet, the outhaul and the portside traveller car haul. Here you can see I have overbored the mounting holes for the rope clutches and the winch base. These will be filled and re-drilled like the description above. The winch will be tilted aft 10 degrees and I will make a tilted base out of thickened epoxy for it. I will install a single clutch and a Lewmar #7 on the starboard to handle the starboard side traveller car haul.
So I want to tilt the port winch about 10 degrees to prevent overrides. If you read the West System manual, the instructions are very detailed: it's easy and quick to do. The most important step is to cover your winch base with some kind of release agent--I use kitchen plastic wrap. The use a couple of scrapes of wood to raise the forward edge, or the edge you wish to tilt. Mark everything with a pencil so you can align it later--also an important step.
The trick here is to position the winch correctly. The pencil marks are crucial. make sure you put enough of a blob down that it fills under the winch base entirely. Then when everything is positioned just so, take a stirring stick or your finger and scrap up the excess that spluged out.
Here you see the edges filleted nicely, and the base ready to kickoff and harden. I took a piece of tape from the companionway side to the top of the winch just to secure it so it doesn't shift down the top of the cabin.
This is the second solar vent I am installing; the other being in the lazarette hatch. It is a Nicro 2000 Day/Night solar vent, requiring a 4-1/2" hole cut in the cabin top. I am locating it forward of the dorade box and as close to the mast step as I can get. Here is the mark on the cabin. I drilled a 1/4" hole at the mark to confirm it was located ok inside the head. Then I used the drill bit in the hole to locate the center of a plywood trim ring I cut that will be used to mount a second deck plate inside the head. I epoxied the trim ring in place.
The I used my monster 1/2 drill and hole saw to cut the hole in the cabin top. Once again it is very reassuring to see bone dry balsa coring. I used a narrow chisel to dig out the balsa from around the edge of the hole, back about 1/2". I thoroughly wetted the balsa out with unthickened epoxy, and used a caulking tube to inject a very thick mixture of epoxy and 404 high density filler into the gap.
When the epoxy hardened I took a drum sander on my drill and eased the top edge for the deck plate and smoothed the vertical edge of the hole. Here you can see that the deck plate fits flat against the cabin top in this area. Then I test fit the solar vent. The location is ideal for me. I do very little mast work on the port side of the mast and when I do I can comfortably position the vent between my feet. Here is a shot of the vent from inside the head. Still needs some work but I am waiting on the interior deck plate first before I continue.
The mainsheet comes off the boom at the most forward block, and down to a standup block mounted on the mast step. I call it the mainsheet return block since the sheet makes a turn around it and leads back to the sheet stopper and winch at the aft end of the cabin. Mounting the block is straight forward--it is the location where the original block was, but I relocated it to the end of the mast step so it makes a fair lead around the aft uprights of the dorade guards when the boom is all the way eased.
First I drilled oversized holes, in this case down about an inch to the steel plate that is part of the mast step support system. I fill the holes with epoxy thickened with West System 404 High density Adhesive.
Then, I drilled a 7/32 tapping hole for the tap thru the metal plate and down about 2 inches. The Garhauer block accepted #10 screws for mounting, but I drilled out the holes to accept 1/4 inch screws instead. I like the extra beef here. Then I tapped the holes for 1/4 inch long 1-3/4 inch pan head machine screws.
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