Adding New Bulkhead for 22-foot Hulls with Narrow Splash Wells

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Vance's Revenge
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Joined: Wed Nov 25, 2015 2:37 am
Location: Northern California

Adding New Bulkhead for 22-foot Hulls with Narrow Splash Wells

Postby Vance's Revenge » Tue Apr 06, 2021 1:41 pm

While researching the possible use of transom boards to prevent water from coming over the transom of my 1980 Revenge 22, I developed another solution for 22-foot boats that have the narrow, sink-style engine splash well instead of the full width engine splash well used on later 22-foot hulls.

My solution was to put the main engine on a jack plate which moved it off the stern by 5-inches more clearance while at full tilt. This allowed me to make a new cockpit bulkhead at the inboard edge of the original engine splash well dam. Next, to prevent water catching on each side of the stern, I raised the deck height to match the height of the original engine splash well dam.

To create drains for the cockpit, I added five fiberglass drain tubes of 1-1/4-inch-inside-diameter at deck level across the new aft cockpit bulkhead. The center three tubes drain into the original engine splash well.

To create the new aft cockpit bulkhead I used 1/4-inch marine plywood that was completely sealed with West Systems epoxy and one layer of fiberglass. For strength I doubled the plywood at the bottom on the inboard side.

The top [of the aft cockpit bulkhead is] is 1-inch by 5-inch mahogany, which attaches to the boat's original mahogany gunwales. For extra strength the entire bulkhead is fared in place with West Systems Six10 epoxy.

My Evinrude 225 does not have a tilt limit switch so I made a door [in the new aft cockpit bulkhead that can] open for clearance at full tilt of the engine.

You will notice in the Figure 2 and Figure 3 the fuel line now passes through the original dam of the engine splash well. I drilled through [the original splash well dam] and epoxied in place a stainless steel nipple.

This new bulkhead creates nice place to install a water-fuel separating filter out of the way and above water level.

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Fig. 1. A view of the new, full-width aft cockpit bulkhead as seen from astern.
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Fig. 2. A fuel-water separating filter has been mounted on the new aft cockpit bulkhead on the outboard side.
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Fig. 3. A door cut into the new aft cockpit bulkhead permits the main engine to be tilted up as far as possible.
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Vance's Revenge
Posts: 116
Joined: Wed Nov 25, 2015 2:37 am
Location: Northern California

Re: Adding New Bulkhead for 22-foot Hulls with Narrow Splash Wells

Postby Vance's Revenge » Tue Apr 06, 2021 4:50 pm

Some notes on the above:

The 1980 Revenge 22 has the old style hull with the small, deep, narrow, engine splash well that doesn't go completely across the stern.

4a.jpg
Fig. 4. The original aft cockpit and transom layout showing the small, center engine splash well. Note the two drain tubes that will eventually create overboard drains that will pass through the aft cockpit bulkhead to be fabricated.
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Adding a gunwale-height aft cockpit bulkhead like this blocks off the access from the rigging tunnel to the stern, so on an Outrage the rigging would best be run from the rigging tunnel to the cockpit drain sump (original route) then up on under the starboard gunwale and out to the motor. But since my boat is a Revenge [without a center console and with the helm on Starboard] , all rigging goes down along the gunwales. The fuel line goes as described.

5a.jpg
Fig. 5. The new aft cockpit bulkhead plywood in place, and new raised deck level on outer deck around the original narrow engine splash well. Also note two of the three drain tubes are visible that drain the cockpit through the new aft cockpit bulkhead.
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The stainless nipple I installed goes from the cockpit live well under the floor through the sub-floor bulkhead and into the engine splash well. Shown in the picture after paint, but the fuel line was pushed into the drain sump when this picture was taken and not attached yet. This change in the fuel line route could be done on an Outrage as well.

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Fig. 6. In this view the original fuel hose routing is still heading into the cockpit sump, but it will soon be moved to connect to the fitting that passes through the engine splash well.
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The aft cockpit bulkhead took time to design, but was not that difficult to do.

padrefigure
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Re: Adding New Bulkhead for 22-foot Hulls with Narrow Splash Wells

Postby padrefigure » Fri May 28, 2021 12:06 pm

Your work is beautiful and addresses the biggest concern with the older 22 hulls that I have seen. A couple of questions for you:

If you had installed a 10-inch set back bracket, could you have avoided the hinged cut out [refer to Fig. 3] in the bulkhead for tilt clearance?

The Starboard rigging tunnel [refer to Fig. 6 and seen at the top] appears to have a small bulkhead separating it from the overboard drain sump ahead of the original bulkhead and outboard of the live well. Did you add that?

The live well [refer to Fig. 6] appears to have two drains to the sea along with the original drain through the bulkhead to the sink splashwell. Did you add those?

Again, very nice work. In this model, it appears that Boston Whaler did not know quite what to do with this space so sort of just stopped designing, leaving some loose ends.

Vance's Revenge
Posts: 116
Joined: Wed Nov 25, 2015 2:37 am
Location: Northern California

Re: Adding New Bulkhead for 22-foot Hulls with Narrow Splash Wells

Postby Vance's Revenge » Fri May 28, 2021 2:25 pm

padrefigure wrote:Your work is beautiful and addresses the biggest concern with the older 22 hulls that I have seen.


Hi Padrefigure, Thank you for the kind comment.

padrefigure wrote:If you had installed a 10-inch set back bracket, could you have avoided the hinged cut out [refer to Fig. 3] in the bulkhead for tilt clearance?

I originally thought about the 10-inch set back bracket to make clearance. But, these narrow bottom hulls don't perform well with a lot of additional weight on the transom and moving the engine back 10-inch adds dramatically to that equation. My goal was to keep the total weight of the engines and rigging on the transom equal to the original weight of twin 115-HP two-stroke engines. My design (with a raised kicker) added additional torque to the transom so I felt it needed to be reinforced to spread out the added pressures. For strength, I added full width by 13-inch high 1/4-inch aluminum plate both inside and outside of the transom.

I believe in mounting my auxiliary engine high to keep stern swell and waves from splashing into the power head so I mounted 1 x 12 x 19-inch aluminum plate to the transom to raise the auxiliary engine to the extra-long-shaft height; this brought the bottom of its power head very close to the bottom height of the main engine. I don't remember the figures now, but the weight of the aluminum added to the transom, the jacking plate, the 1-inch auxiliary motor mount plate, the 9.9 Yamaha High Thrust kicker, along with the 1986 Two Stroke Evinrude 225 came out very close to the weight of two 115-HP engines the hull was designed for. I'm a big fan of two-stroke power and this could not be done with a new V6 four-stroke-power-cycle engine, so I had the 1986 Evinrude 225-HP engine rebuilt from the flywheel to the propeller shaft. This keeps the boat to a retro mode, and the boat performs terrifically.

Now that I think about it, if using a newer engine that has a limit switch on the trim, then a 5-inch set back bracket would work without the door at the top of the new stern bulkhead.

padrefigure wrote:The Starboard rigging tunnel [refer to Fig. 6 and seen at the top] appears to have a small bulkhead separating it from the overboard drain sump ahead of the original bulkhead and outboard of the live well. Did you add that?

My boat is a 1980 22 foot Revenge. My goal was to stop any water from getting to the fuel tank and I achieved that goal in part by running the rigging down the gunwales instead of utilizing the factory rigging tunnel. This allowed me to add that bulkhead you mentioned bow side of the drain sump. The bulkhead is made from foam sheet cut to shape, fiberglass and west systems epoxy. This allows the drain sump to be utilized as designed but blocks water from getting into the original rigging tunnel. I put a 1-inch tube and plug at the bottom of that mini bulkhead for inspection (via access through the drain sump) to periodically check to see if water got past it.

padrefigure wrote:The live well [refer to Fig. 6] appears to have two drains to the sea along with the original drain through the bulkhead to the sink splashwell. Did you add those?

When the new stern bulkhead is added, it creates a high and incredibly seaworthy engine well, but the bulkhead blocks off the original design of the cockpit draining over the stern in an emergency situation. To solve the draining problem of the full height bulkhead and prevent a dreaded brass corrosion concern, I added five fiberglass 1-1/4-inch ID tubes at deck level (seen clearly in Figure 3 finished shot and Ffigure 5 under construction) across the bottom of the stern wall. The three drains in the middle drain into the original drain sink (pictured below next to the tape measure) and the port and starboard tubes drain out the stern. To prevent water from running backwards from the sea onto the deck I mounted ping pong style scuppers on the stern side of each tube.

This system has also worked incredibly well.

Re the other supply/drain lines you see in Figure 6:

To supply sea water under the deck to my removable live bait tank that I have mounted on the deck (see the tank in Figure 3) I ran a fiberglass tube through the original bait tank bulkhead into the original drain sink. To thread the tubes, I waxed the threads on the fitting, cleaned the tubes and used Marine-Tex packed around the fitting to create the threads in the the tubes. Once the tube was threaded I could utilize standard fittings to make the manifold to feed the bait tank. The other line you see in the port side rigging tunnel go through a fiberglass tube I installed which runs up the rigging tunnel, across the fuel tank and up behind the starboard inspection cover at the side of the hull to a washdown pump mounted out of sight behind the stern side cabin structure.

The 2-inch vertical fiberglass drain tube in the bow/middle of the original bait box is the drain for my bait tank that necks down from 2-inches at the top to 1-1/2-inches where it exits out the bottom of the hull. I have a clam shell where it drains similar to all the other drains on the bottom. The top is threaded with Marine-Tex, and I installed a quick release fitting to the top. You can see a similar quick release fitting on the supply line on the PVC manifold in the picture. The supply and drain on the bait tank route up through a 4-inch-diameter removable deck plate (seen in Figure 3) on the deck that I reinforced, and I cut a 1-3/4-inch hole and a 3/4-inch hole in to run the drain line and the supply lines through. I bought a second deck plate for the lid to install when the bait tank is not installed. This system works very well and takes only about a five-minute-process to remove or install the live bait tank.

Pictures below of the stern side transom 1/4-inch aluminum plate etched, primed, and painted to match the hull with Awlgrip paint. This looks pretty bad pictured as a close up. But it isn't nearly as noticeable otherwise.

Whaler pic inside transom pic tape measure show distance to stern wall.jpg
Fig. 7. Transom splash well. A tape measure shows the distance between the transom and the new full-height bulkhead added in the modification. The distance appears to be about 14-inches
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Whaler pic Transom stern side shot of .25 aluminum reinforcement.jpg
Fig. 8. Transom outboard side showing the added aluminum plate to reinforce the transom structure for the added auxiliary engine.
Whaler pic Transom stern side shot of .25 aluminum reinforcement.jpg (69.92 KiB) Viewed 5293 times
Last edited by Vance's Revenge on Fri May 28, 2021 6:47 pm, edited 2 times in total.

jimh
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Re: Adding New Bulkhead for 22-foot Hulls with Narrow Splash Wells

Postby jimh » Fri May 28, 2021 3:12 pm

padrefigure wrote:The live well [refer to Fig. 6] appears to have two drains to the sea along with the original drain through the bulkhead to the sink splashwell. Did you add those?


I think the question refers to the two drains through the hull bottom to the sea in the aft live well and a third drain into the original deep splash well. Perhaps we can get a comment on those three drains.

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Re: Adding New Bulkhead for 22-foot Hulls with Narrow Splash Wells

Postby jimh » Fri May 28, 2021 3:16 pm

Regarding the new bulkhead added to prevent the rigging tunnel from connecting to the cockpit sump on starboard:

Wouldn't water be able to get into the rigging tunnel at the cockpit end of the rigging tunnel if the deck became flooded with water?

Vance's Revenge
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Re: Adding New Bulkhead for 22-foot Hulls with Narrow Splash Wells

Postby Vance's Revenge » Fri May 28, 2021 3:28 pm

jimh wrote:
padrefigure wrote:The live well [refer to Fig. 6] appears to have two drains to the sea along with the original drain through the bulkhead to the sink splashwell. Did you add those?


I think the question refers to the two drains through the hull bottom to the sea in the aft live well and a third drain into the original deep splash well. Perhaps we can get a comment on those three drains.


Thank you Jim. I think I understand his question better now.
The two holes in the original aft live well are factory. One in the stern side bottom and through the stern bulkhead into the motor drain sink are original. I did replace those original brass tubes with the original size ID fiberglass tubes and sanded them flush. Now they will never corrode/need to be replaced and drain better. I replaced all drain tubes in the hull with the same process. The other dark object in the picture is the handle of a shut off valve on pvc bait tank supply manifold. The black handle makes it appear like a hole.

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Don McIntyre - MI
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Re: Adding New Bulkhead for 22-foot Hulls with Narrow Splash Wells

Postby Don McIntyre - MI » Fri May 28, 2021 5:10 pm

Excellent work and finish work. Only small suggestion I'd have is (probably too late) to consider making the door for the engine clearance spring loaded. No accidental tilting up to far and cracking the great looking door!

Regards - Don

jimh
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Re: Adding New Bulkhead for 22-foot Hulls with Narrow Splash Wells

Postby jimh » Fri May 28, 2021 8:22 pm

Regarding the large diameter drain added to the aft live well as seen in Figure 6, there is much additional information given in a separate article that focuses on the live well changes. See

REVENGE 22 Live Well Modifications
https://continuouswave.com/forum/viewtopic.php?f=6&t=6018

Vance's Revenge
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Location: Northern California

Re: Adding New Bulkhead for 22-foot Hulls with Narrow Splash Wells

Postby Vance's Revenge » Fri Jun 04, 2021 8:24 pm

jimh wrote:Regarding the new bulkhead added to prevent the rigging tunnel from connecting to the cockpit sump on starboard:

Wouldn't water be able to get into the rigging tunnel at the cockpit end of the rigging tunnel if the deck became flooded with water?


Hi Jim,
I didn't see your question until now.
The 1979 and 1980 Revenge models have a one piece floor cover over the fuel tank. This creates a huge job to remove the cover because both of the cabinets at the helm have to be removed for access. You are correct, originally the factory cut a square hole in the floor cover under the helm cabinet and ran the rigging down through the floor cover into the rigging tunnel. While I had the cabinets out and to prevent water from accessing the this factory access hole; I blocked it off with plywood, fiberglass and West Systems epoxy. While I had the cover off, I cut it along the cabinets similar to the factory change on later Revenge model boats. This way, if there is ever a need to get into the fuel tank area, the cabinets will not need to be removed.
This picture of the floor cut was taken prior to finish/paint
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Whaler Pic Floor Cut-rough unpainted.jpg
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