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PDQ 34 Berth Modification
Hey!
I mistakenly posted this in the Welcome board. Opps!
Also we'd like to try out a PDQ 34 for a long weekend or so in the Chesapeake Bay area.
Thanks in advance.
Drew Dolak
Postby OldGeek on Mon May 04, 2009 10:45 am
Hi All!
We're upgrading our cruising lifestyle. We had Hunter 450 sailboat but though comfortable it was too deep at 5'-6" draft to go all the places we wanted. Our present boat is a Motorcat 30, shallow at 1'-6" but not as comfortable as we'd like.
We're considering the PDQ 34 power cat yet the queen berths are a tad too small. So the question: If the locker adjoining the starboard berth is eliminated this would allow enlargement of at least 18" fore and aft, and 36" port to starboard. Then realigning the berth to a larger fore/aft configuration would follow, about 72" port/starboard by 78" fore/aft. Vessel structure may be the critical issue, and some compromise will almost certainly be necessary. Perhaps a compression post to support the corner of the deck above. This would be minimal interference with the berth.
I am going to venture a speculation, clearly I have not tried such a modification. I did just move the 200 amphour house battery bank (80 lbs total?) from the stock aft 'midships position to a pair of 820 amphour, 328 pound each batteries, mounted symetrically port and starboard in the lockers in question, so I have studied the structural issues in that specific spot.
I believe that your plan would significantly compromise the strength of the entire hull, even with a compression strut. If the boat never again was subjected to bumpy water, the 'static loading' would likely not pose any damage, but where the hull is subjected to the stresses of moving in rough water -- 'dynamic loading,' I strongly suspect that there would be problems.
The bulkhead which forms the aft portion of the aft starboard locker is the load bearing bulkhead directly beneath the aft edge of the house structure, and bears the vertical load from the flybridge and the aft starboard corner of the house to the hull. Removing the particularly important end section will likely lead to significant flexing of the deck above -- potentially leading to cracks in the deck, the house outer surface and internally to the remaining end of the bulkhead and elsewhere. Attendant distortion/compression of the strength providing thickness of the corcel core would be likely. There may be a decrease in the strength of the entire hull to resist distortions like twisting, where one bow is lifted before the other. The hull is not a post-and-beam structure which lends itself to moving posts about; rather it is a monocoque structure, like a modern frameless automobile, where posts are replaced by bulkheads and beams by entire decks, bonded together along their entire lengths into intrinsically strong shapes (like boxes, tubes and such). The outer shell of the PDQ powercat, like most modern boats is such a carefully designed monocoque. Note that there are no stanchions throughout the entire cabin (helm area, dinette area and hulls on both sides, and that boat movement and various loadings produce no discernible flexure. Also note that the aft starboard corner of the main fuel tank is just behind this bulkhead. This is the single heaviest item aboard.
Furthermore, the upper surface, inner surface and forward surface of that locker are not vacuum bagged corcel foam (the rigid hull and decks) or bagged plywood (the bulkhead we were discussing above); rather it is mostly paper honeycomb core with light wood veneers bonded outside. In the original design these are not load bearing, and although a compression stanchion and load distributing beam could probably be devised, the space it would require would be a significant problem and hull flexure would likely still be an issue, pivoting on the top of said stanchion.
Last, I find that although the standard queen sized bunk is quite adequate for the generously proportioned Admiral and I, the difficulty for the aft partner getting out in the middle of the night (every night at our age) requires waking the other. We resolve this by each taking a private cabin. Each has lots of room to sprawl, twice the locker space and we don't disturb the other. Your mileage might differ, but that works just fine for us. We VERY rarely take another couple on an overnight, and compromise those gains on those rare occasions.
Gary Bell, STRAY CAT, MV34, hull 12
Candy Chapman and Gary Bell in Stray Cat, MV34 hull 12
Your analysis and answer is thoughtful and quite complete. This is exactly what I was looking for from an experienced owner. Thank you.
I understand the desire for an enormous house battery bank and those humongous Rolls you've installed are certainly the answer to hanging on the hook for days at a time.
Now I have to find a PDQ 34 that we can try out for a few days on the Chesapeake.
Re: batteries. We have six 6-volt golf cart batteries that fit in the standard center aft compartment. This gives about 620 amp hours. Not the 800+ that Stray Cat has, but we find the 600 adequate for two nights at anchor (with above-average load), which has been enough in our experience. We don't have a generator. We installed "smart" alternator controllers to insure rapid recharge under power. I have considered carrying a portable Honda 1000 or 2000 watt gasoline generator in the flybridge space alloted to an Igloo cooler we never use.
