Follow by Email

Tuesday, July 3, 2018

Aft mast boom modifications

To safely lift the dinghy onto the deck cradle required a modification of the boom (that I should have done when I thought of it while we were building the mast/boom parts). The boom is 12' long and does a nice job reaching over the side of the boat for a pick from the padeye at the end of the boom. Once the load is in the air, you need some alternative pick points closer to the mast to transfer the load inboard and onto the aft deck. While I was building the new dinghy cradle, I pulled the boom off the boat and added a length of  3/8 x 1.5" flat bar to the underside, stitched 50/50 to the boom, and drilled every 12" for a shackle.






This allows for multiple pick points along the length of the boom for transferring the load in and out using a pair of 6:1 tackles. The flat bar stiffens the boom considerable and as long as we don't go too crazy with the weight, it should hold up fine with the additional mid-span loading. So far it works great for moving the dinghy and motor around. If we needed to hang some serious weight from the middle of the boom, we would move the topping lift to directly above the pick-point we are using on the boom. I don't have any good pics of using the rig for lifting (was too busy keeping track of things the first time around) but I'll post some more detailed pictures of lifting and moving big heavy stuff with this rig at some point.



On deck dinghy storage

Our aft davits are super convenient for hauling and storing our dinghy, and are plenty stout enough to carry the boat w/motor attached in most conditions without worry, but going offshore coastal is another story, especially in our area of the Central/North Coast. To many unpredictable factors out there to keep me comfortable with 250 lbs of dinghy hanging off the back of our boat when travelling. With our trip down to Southern California coming up in a few months, I have secure on-deck storage of our dinghy and motor high on the to-do list.

Our aft deck is cambered, with an overlayed flat Ipe wood deck for lounging. The deck is built around the a big aft cabin deck hatch. When we were building and welding out the hatch coamings, I had four stainless 3/8" chain half links installed at each corner of the hatch coaming. I figured they would come in handy for tying down emergency hatch covers or securing the hatch tightly closed if the latching hardware ever broke. These tie downs are now buried under the aft wood deck but with a little work, seemed like a good way to anchor a deck cradle for the dinghy. A set of 3/8" stainless U-bolts through the wood deck and hooked onto the tie-downs did the trick, and provided four strong points to secure the cradle to the deck.






The dinghy cradle design kind of evolved (like most of the boats fit-out) from a scratch design on a napkin. I wanted a rail style mount that was adaptable to other dinghys and skiffs. It had to be stowable so we can turn the aft deck back into a proper lounging pad when we get where we're going and put the dinghy back on the davits. I also want to maximize the light coming in through the deck hatch for the cabin below, and the hatch needs to open wide enough to allow emergency access in and out of the aft cabin when a boat is stowed on the cradle. Here's what we came up with.

The basic concept:



Speed Holes (to make it go faster):


Flat bar stiffeners:



Deck mount brackets added:



Checking fit-up for rails:


Fabricating rails. 2x4 redwood, notched, varnished, and carpeted
(the ONLY brightwork on the exterior):



The finished product:



Outboard goes on a home-made rail bracket (or can stay on boat):



Watermaker Installation

Big expensive new toy arrived from Spectra. We decided to dedicate the time and money to a water maker installation due to our past experience with water management and sourcing water fills while cruising. We don't have a ton of water storage onboard and getting good fresh water while cruising is a hassle. If we watched our use, we could make our existing tankage work, but we like our showers and regular fresh water washdowns keep steel boats and deck equipment much happier.

We went with the Spectra Cape Horn 330. This WM has two electric 12V pump/filter units and a 48" membrane with Clark Pump for boosting the pressure. You can run both 12V pumps for about 15 gallons per hour of fresh water output using about 16 watts of 12VDC power (or about 1.4 amps) per gallon produced, or just one 12V pump for half the output. I also like the back-up that two independent pumps provides. 

On most days we are not using all of our solar output midday. The house bank is charged up by 11am or so at our current latitude- even earlier in the summer. At that point we are just floating along with 50-60 amps of DC solar power to spare, until the sun starts going down and our use starts to exceed the solar output again. So we have lots of extra power available to make water through the middle part of the day without draining the house battery bank. Also, when underway with alternator cranking there is usually plenty of output available. If we take advantage of these high output scenarios for making water, I don't see any major effect on our power reserves vs consumption.

Everything came nicely packed in one big (heavy) box:




Now that I am most of the way through the install, I can say that I am very impressed with the detail provided in all the parts bags and instructions. They really include just about all the little bits and pieces you need for the installation. Of course I couldn't help doing a little customizing...

The different modules come loose, which gives a lot of flexibility on installation (vs one big frame mounted package). I spent a couple of weeks puzzling over where to fit all the components. I decided to mount the pump/pre-filter modules in the ER and the membrane/Clark Pump assembly below deck in the companionway just outside the ER (the membrane does not perform well in hot spaces).

The Clark Pump is a dual acting piston pump that boosts pressure coming out of the DC pumps to the higher pressures needed for the membrane filter to separate the salt out of the feed water. Hanging this heavy assembly in the below deck space was a little tricky, but the addition of an isolation mounted aluminum plate to hang the unit from made things a little easier to hang in place below the deck, and clear of any interferences:







The rest of the components (2 pump/pre-filter modules, control panel, accumulator tank, etc.) required a lot of custom brackets but was pretty straightforward:










There is lots of plumbing between components but nothing too complicated. They use a combination of braided vinyl water hose and push-to-connect plastic tubing- all good quality stuff. I added some fittings and valves to customize the install a bit. The feed water supply for the water maker came off the existing seachest that supplies the anchor washdown pump and shaft seal flushing feed.

Seawater supply valve and secondary strainer:


Brine water discharge from the WM goes to the flanged overboard fitting:


Installed a new accumulator tank for the fresh water system while I was in the neighborhood:


Also cleaned up the fresh water tank supply manifold plumbing and valves:


Fresh water flushing valve for cleaning the WM filters after use:


WM pump breakers, tank fill distribution manifold, pump/filter modules:


Running 3/8" tubing from the WM to the water tanks:


So that's the bulk of the work. I still have a few tubing connections to make at the tanks and the pressure and flow gauges- probably a few hours more to get these done. The water in the Bay has a lot of suspended sediment, plankton, and other little stuff that could clog up the system pretty quick. Testing will have to wait until we take a test run outside the Golden Gate in some nice clean ocean water. 






Sunday, May 6, 2018

A New Cruising Dinghy

Made the big switch from our old fiberglass rowing skiff to a new Achilles RIB.

Here's a few pics of the new boat. More details and pictures on our new cruising blog:

kamahelecruising.blogspot.com