PDQ 36 for offshore passages?

[Budawang]

I have my eye on a PDQ 36 catamaran, but am wondering about its suitability for long blue water passage-making. While most of my sailing would be coastal, I would like to sail one across the Pacific to Australia and possibly even circumnavigate.

My research suggests the PDQ 36 is a good quality, fast cat offering decent live-aboard space for two people at a reasonable price point. I guess the main objection to them for ocean passages is their limited load bearing capability and their outboards' lack of range. However, given their good sailing performance would motoring range be such big deal? Would a water maker help address the weight issue? How big an issue would it be for two people? Would transom extensions help? Are there any other factors affecting their blue water suitability? How safe would they be in a big blow?

[Southern Star]

People have crossed oceans in virtually any kind of boat - indeed, people have even done it in a Gemini. While the construction, bridgedeck clearance and stability of a PDQ 36 are much more suitable than a Gemini, I would still have some concerns.

Size does matter and a 36 foot cat is more likely to capsize/pitchpole than a cat that is 10% longer (or about 40 feet). In addition, displacement is also a factor in capsize resistance and the PDQ is much lighter than most 38 to 40 foot cats.

PDQ did produce a version with diesels (the LRC, or 'Long Range Crusier') although frankly, I would prefer the outboard version for various reasons, not the least of which would be sailing performance and load-carrying capability. The leading edge to the bridgedeck is also rather blunt and I would have some concern about being able to use the forward berths in any kind of seas. Some versions do have a single berth in the small aft cabin, so if you are sailing as a couple with someone always on watch, you could always use that as a sea berth.

Yes, a watermaker could overcome the tankage problems - although I would be a bit nervous about relying totally on a watermaker, especially on a boat with a limited charging capacity (virtually none from the outboards should solar prove inadequate to cover the watermaker, the autopilot, instrumentation, refrigeration, running lights etc).. You would also have to increase the size of the house battery bank - and that, of course, would only add more weight.

Could it be done? Yes. Although the load carrying capability is a significant issue and every 1000 pounds added has a much greater impact on a boat that displaces under 8,000 lbs than one that displaces 20,000.

Brad

[Sand crab]

In the smaller size category a Laggon 380 would be better suited for your needs.

[smj]

Originally Posted by Southern Star

People have crossed oceans in virtually any kind of boat - indeed, people have even done it in a Gemini. While the construction, bridgedeck clearance and stability of a PDQ 36 are much more suitable than a Gemini, I would still have some concerns.

Size does matter and a 36 foot cat is more likely to capsize/pitchpole than a cat that is 10% longer (or about 40 feet). In addition, displacement is also a factor in capsize resistance and the PDQ is much lighter than most 38 to 40 foot cats.

PDQ did produce a version with diesels (the LRC, or 'Long Range Crusier') although frankly, I would prefer the outboard version for various reasons, not the least of which would be sailing performance and load-carrying capability. The leading edge to the bridgedeck is also rather blunt and I would have some concern about being able to use the forward berths in any kind of seas. Some versions do have a single berth in the small aft cabin, so if you are sailing as a couple with someone always on watch, you could always use that as a sea berth.

Yes, a watermaker could overcome the tankage problems - although I would be a bit nervous about relying totally on a watermaker, especially on a boat with a limited charging capacity (virtually none from the outboards should solar prove inadequate to cover the watermaker, the autopilot, instrumentation, refrigeration, running lights etc).. You would also have to increase the size of the house battery bank - and that, of course, would only add more weight.
orthy
Could it be done? Yes. Although the load carrying capability is a significant issue and every 1000 pounds added has a much greater impact on a boat that displaces under 8,000 lbs than one that displaces 20,000.

Brad

I would agree with a lot of what Brad says but I also have some comments/questions.

If you were to extend the hulls by 4' would that make the PDQ 36 a more seaworthy vessel and why.
I understand the light weight of the PDQ, but given their reduced sail area wouldn't they be as seaworthy as a heavier boat with a larger sail plan?

We jut moved aboard our new to us PDQ 36 so these questions interest me.

[colemj]

Having extended our hulls, I think almost every cruising catamaran out there would find seaworthiness increased with increased hull length - particularly in the sterns. I was shocked at the difference in ours - certainly unexpected.

The difference is the ability to carry a bit more load, much less hobby-horsing and much less stress in the rigging/hull because of less drag and easier (and longer) surfing on runs.

The difference was so great that we had to go through the setup procedures on the autopilot again and let it retune itself to the new hulls. The result was much reduced values for primary and counter rudder at high and low speeds. This tells me that the steering gear appreciates the decreased work also.

Mark

[smj]

Originally Posted by colemj

Having extended our hulls, I think almost every cruising catamaran out there would find seaworthiness increased with increased hull length - particularly in the sterns. I was shocked at the difference in ours - certainly unexpected.

The difference is the ability to carry a bit more load, much less hobby-horsing and much less stress in the rigging/hull because of less drag and easier (and longer) surfing on runs.

The difference was so great that we had to go through the setup procedures on the autopilot again and let it retune itself to the new hulls. The result was much reduced values for primary and counter rudder at high and low speeds. This tells me that the steering gear appreciates the decreased work also.

Mark

I would agree, after extending the hulls of our Seawind by 4' she felt like a different boat, had the motion of a much larger boat. This also increases your wl beam to wl length ratio which is a good thing. My concern would be the overall beam to overall length ratio would decrease and would that have any negative impacts on seaworthiness?

[thinwater]

Ask people who have them:

PDQ Owners Forum • Index page

[Sand crab]

The PDQ hull extension thread:
PDQ Owners Forum • View topic - Hull Extensions

[Factor]

It will be fine. As for outboards lack of range, no sailing cat under 50 feet carries enough fuel to motor all the way there.

[admiralslater]

One did go transatlantic in the early days

[Southern Star]

smj, putting on hull extensions is really a win/win/win/win situation. Yes, they will increase the length of the waterline, which will improve hull speed. Yes, they will also provide not only additional bouyancy aft, but also some additional load carrying ability aft (for additional solar panels etc.).

While the BOA to LOA ratio would be reduced, that would not have an adverse effect on transverse stability unless the sail area and/or Ce of the sailplan were also raised. Some naval architects have developed formulae for wave heights that can cause a capsize in a catamaran and, while I do not fully understand the physics, the required wave height is proportional to not only BOA (which I do understand), but also LWL. Regardless, due to the increased displacement that will result with the hull extensions, the resistance to capsize will also be increased slightly due to that factor (all else being equal, in both monohulls and monohulls, a wave will move a heavier displacement hull less than a lighter displacement one). So, in the final analysis, your resistance to capsize will increase with hull extensions, even though the BOA to LOA ratio has decreased.

Moreover, resistance to pitchpoling actually increases with not only an increase in LWL, but also with a decrease in the ratio of BOA to LOA: Think of two joined logs that are side by side and separated by a distance of only four feet. If you stood on the end (bow) of one log, it is less likely to be submerged than if the logs were separated by 10 feet. Why? Because you are getting more resistance to burying the end of the log you are standing from the end of the other log if they are closer together. Furthrmore, additional length has the same effect: if you stood on the end of a 4 foot long log, it would be much more likely to tip end over end than if you stood on the end of a 10 foot log. It is for these reasons that many naval architects warn of the increased risk of burying a bow on many of the new catamarans that have BOA to LOA ratios significantly in excess of 50%. In any event, not only will your resistance to capsize increase, so too will your resistance to burying a bow and pitchpoling.

As if any more justification is needed, we must add to the above the reduction in hobbyhorsing and the ability to have a proper swim/dinghy boarding platform aft and it really is a win/win/win/win situation in terms of performance and stability.

While I have little doubt that a PDQ 36 with 4 foot hull extensions would be as capable of safely handling the same seas as other 40 foot catamarans, I still have concerns about the load carrying capacity for something as long as a Pacific crossing. Yes, it could be done. However, one would have to be extremely careful so as not to overload the boat with equipment, supplies and stores. While on a boat such as a Lagoon 380, one could readily carry not only a watermaker, but the additional weight of more charging capability and a large house battery bank, I suspect that the same may not be true on the PDQ. In the end, I suspect that even with a crew of two, you would have to be careful in rationing your water.

Brad

[smj]

Thanks Brad, once again you've explained things in a way that even I can understand! There's no doubt stern extensions make a huge difference in motion, load carrying capability and extra performance. Here's a picture of our old Seawind 1000 that we did stern 4' extensions on 5 years ago. It was an easy picture to get as we are
Moored next to them at the moment.
http://share.findmespot.com/shared/faces/viewspots.jsp?glId=0fNVtOsSq0IfHPIbsVGFdOOxDqAXgRV 8H


Sent from my iPhone using Tapatalk

[Southern Star]

Well done, SMJ. The pictures I have seen of hull extensions on a PDQ 36 appeared to be even more simple - they did not add a sweep back from the deck to the top of the extension, but rather only a hull extension in the form of a swim platform. I believe that someone on this site with a PDQ 32 did similar DIY extensions and was very happy with them.

One other concern that came to mind with the PDQ 36 (apart from load carrying capability and the blunt leading edge to the bridgedeck), are the holes on the inside of the hulls aft of the bridgedeck to permit passage of the exterior stainless steel tube that connects the rudder heads. I have always wondered whether they would take on water in following seas. Perhaps some kind of silicon or rubber baffles, or even a Sunbrella cone could be installed which would allow the tube to move in and out of the hulls, but eliminate, or at least reduce the potential for water intrusion.

Brad

PS smj, you change cats more often than I have changed spouses - in fact, way more often! I somehow failed to realize that you were now the proud owner of a PDQ 36. I am quite familiar with the boats, livng only a short distance from where they were built and having one stored beside me over the years at my current marina. In fact, I had the pleasure of a test sail on hull#1 after the Toronto Fall In-Water Boat Show many years ago (although at that time it was the PDQ 34, prior to the addition of PDQ's own hull extensions).

[Budawang]

Great replies. Thanks. The consensus, it sounds, is that the PDQ is not really suitable for crossing oceans although they might be with hull extensions which make a huge difference. Makes me wonder why more manufacturers aren't doing it, presumably at little extra cost when not retro-fitted. I believe most if not all new Seawind 1000s now come with the extensions.

I also wonder why a Mahe 36 is rated as a blue water offshore capable boat. Same length and only slight higher displacement. Maybe it's down to wider, more buoyant hulls.

Are there some safety advantages to a lightweight cat? In reality don't cats simply get pushed forward out of harms way rather than getting pooped when in large, breaking, following seas? A light displacement cat would be pushed forward more easily. Perhaps a bigger concern is getting pushed forward too fast and burying bows in the trough (although a drogue would mitigate this risk).

[Sand crab]

Remember that the PDQ was originally a 34. When they stretched it you still had the same interior volume. The Mahe was a purpose built 36 which should have more space. It is also over a foot wider so more there as well. I haven't been on either so this is just my view.
One interesting detail is the PDQs haven't been built for quite a while and the value has bottomed out I suspect. Some of the newer Mahes will probably depreciate a bit more before hitting bottom.