Cabin top fiberglass thickness?

Post here if you want to discuss a topic specific to the PDQ Altair.
Iriemon
skipper
skipper
Posts: 52
Joined: Mon Apr 20, 2015 11:05 am

Cabin top fiberglass thickness?

Postby Iriemon » Tue Apr 26, 2016 2:08 pm

One of the things I don't like about our PDQ 32 is the lack of handholds when you are going forward after you leave the area where the cockpit bimini ends. Once past the bimini top, there's not much to hold onto, which makes it somewhat dangerous going to the bow area of the boat (which we affectionately call the "lounge area"), especially for older guests.

So I found these "shark fin" railings I plan on mounting on the forward outer sections of the cabin top (i.e. cabin salon "roof") so there will be something to hold on to as you go forward. I purchased some bimini fittings to add a third leg to give the railing more horizontal support. I'll drill out and epoxy fill holes in the cabin top, and mount SS backing plates on the interior side of the cabin top (under the vinyl liner).

http://wemausa.3dcartstores.com/Stainle ... p_102.html

The question is, does anyone know the approximate thickness of the fiberglass cabin top so I can know what length machine screws to get? I'm guessing it is a foam core sandwich, but whether it is 1" or 3" or something in between, I don't have a clue.

User avatar
thinwater
admiral
admiral
Posts: 1010
Joined: Mon Sep 22, 2008 8:08 am
Contact:

Re: Cabin top fiberglass thickness?

Postby thinwater » Tue Apr 26, 2016 9:22 pm

Probably 2 layers of 17 oz. biax on both sides, with foam in the middle. How thich the foam is depends on the location, but about 1-inch. A screw will hold about enough to secure a winch handle holder but not much else. You will need to drop the ceiling cover and through bolt or the rails will break and be dangerous. 1/4-inch bolts should do. You will also need a backing plate on the inside, and not just fender washers (they ALWAYS bend with the pressure comes on).

The other choice is a high lifeline. Run a piece of non-stretch line (something with a spectra core) from the rear side gate, up to the shroud about 2' above the lifeline (secure with clove hitch), past the lifeline (lash it), and down to a stanchion base. Tension with a lashing.

Image

Also notice where I run the jacklines (rail to a bolt hanger on the edge of the tramp). This way I have a rope in each hand, secure even in wild conditions.

Image

I kinna like the railing idea, but I think the jackline/high lifeline solution is more practical. The other things I have done to ease access was to add a forward lifeline gate on both sides and booster steps in the cockpit and interior. Wife has a fake knee and I've had several knee surgeries.
Writing full time since 2014.

http://sail-delmarva.blogspot.com/2017/ ... store.html
"Keeping a Cruising Boat for Peanuts"
"Singlehanded Sailing for the Coastal Sailor"
"Faster Cruising for the Coastal Sailor"

Iriemon
skipper
skipper
Posts: 52
Joined: Mon Apr 20, 2015 11:05 am

Re: Cabin top fiberglass thickness?

Postby Iriemon » Wed Apr 27, 2016 4:33 pm

Thanks for the suggestions, Drew. Yes, I know to through bolt the railing bases with a backing plate. I'll also remove as much of the core as possible and replace with solid fiberglass to give the rail mountings a secure support base.

I like your higher life line rig, I'll ponder that as an alternative or maybe an additive for passages. But having a solid railing will have some advantages to. Both my knees have been scoped (too many years of B-ball) though aren't too bad, but I'll have older guests that I know will appreciate something solid to hold onto going forward (and back). Though truth is, I'll appreciate it too. It wasn't after so many trips to the front of the boat that I slipped on the deck and landed on my ass. Thank goodness for the tramps!

Bryan

User avatar
thinwater
admiral
admiral
Posts: 1010
Joined: Mon Sep 22, 2008 8:08 am
Contact:

Re: Cabin top fiberglass thickness?

Postby thinwater » Thu Apr 28, 2016 5:05 pm

Yup, I feel you with the knee and balance issues. I put an article on ergonomics in Practical Sailor a few months ago I titled "Tall Step Disease." The PDQ 32 has a few problems:
* high steps (wooden box steps help)
* high helm seat (put a shelf to stand on)
* steps into the hulls (added hand holds)
* Climbing into the bunks (mini-sea chest)

My concern with fixed rails is line snagging (genoa sheets) and lateral bracing. Will they withstand a 100-pound pull to the side? I think you need a side brace or to add a backing plate on the top too.

The ropes actually work really well, if you can learn to pull up, not push down.

I also added a non-stretch line from the end of the jib traveler to the lazy jack pad eye on the mast. I added it to solve a line snagging problem, but it also a handy hand-hold. (see what I am clipped to, below)

http://sail-delmarva.blogspot.com/2015/07/more-jacklines.html
Image
Writing full time since 2014.

http://sail-delmarva.blogspot.com/2017/ ... store.html
"Keeping a Cruising Boat for Peanuts"
"Singlehanded Sailing for the Coastal Sailor"
"Faster Cruising for the Coastal Sailor"

Iriemon
skipper
skipper
Posts: 52
Joined: Mon Apr 20, 2015 11:05 am

Re: Cabin top fiberglass thickness?

Postby Iriemon » Fri Apr 29, 2016 3:21 pm

I plan to drill out and remove the inner foam core under the railing base and rebuild with epoxy and glass mat to make a strong enough base to secure the rail without crushing the cabin top. I've got a jaw clamp and base and 12" of SS tubing to make a third leg to give the railing lateral strength. That, along with SS backing plates on the inside of the cabin top, should give it plenty of strength as long as someone doesn't use it for a towing point or something like that.

It won't interfere with the standard jib I have because the jib hardware is forward of where the railing will be. It might interfere with the sheets of an overlapping genoa, though I'd think if you give it enough slack on the windward side the sheet would probable stay in front of the railing. If it was a problem you could run a line from the railing to the mast and to the other railing to keep the genoa sheet from falling on the inside of the railing, kind of like what you did already.

We plan on living aboard the boat, possibly for several years. While installing the railing is a pain and it may look a little ungainly, I think it will be worth it to have that hand hold to steady yourself when going forward and back on a day-to-day basis.

User avatar
thinwater
admiral
admiral
Posts: 1010
Joined: Mon Sep 22, 2008 8:08 am
Contact:

Re: Cabin top fiberglass thickness?

Postby thinwater » Sat Apr 30, 2016 11:45 am

Yup, sounds strong.

If you see a genoa in your future I would give that very serious consideration to the design. Yes, tacking with a genoa is more work, but the boat is much more weatherly, better balanced, and considerably faster (knots, not fractions) on all courses. I spent much of yesterday trolling in an 6- to 8-knot breeze under genoa alone, and it gave me the 3-4 knots I wanted without having to fool with the main while fishing. Tacking in any sort of breeze, even 8 knots, the sheets flog everywhere; I added the vertical lines to keep them off the mast-mounted winches. The inboard line you are seeing is a jackline. If I tied it to the railing it would interfere with jackline useage, though I think you could work around that. Perhaps you do not feel you need jacklines, but I singlehand most of the time so I do.

If your knees give real trouble with that step-down, I see the need. My wife has a lot of trouble in that area and only comes forward in very calm conditions. She generally solves the problem by going closer to the bow and backtracking. Counter intuitive but effective. Adding aggressive non-skid helps. We've added strips many places, including all the steps and steep slopes.

Image
Writing full time since 2014.

http://sail-delmarva.blogspot.com/2017/ ... store.html
"Keeping a Cruising Boat for Peanuts"
"Singlehanded Sailing for the Coastal Sailor"
"Faster Cruising for the Coastal Sailor"

Iriemon
skipper
skipper
Posts: 52
Joined: Mon Apr 20, 2015 11:05 am

Re: Cabin top fiberglass thickness?

Postby Iriemon » Tue May 03, 2016 5:51 pm

I am considering a genny for the reasons you mentioned. Also, I found on the other cat I owned (an Island Spirit 37) that allowing the jib to back just a bit on a tack before releasing helped the boat tack better. I don't know if that tactic would work on the 32, but you can't do it with the self tacking jib, which just flogs uselessly on a tack. The 32 is significantly slower to tack than the Island Spirit, and likes to head up, I suppose because of the forward keel placement as you have commented on, though I'm no boat designer. I noted from your blog (which is wonderful, btw) that you extended the keels a bit -- did it help enough to make the mod worthwhile?

If I get a genny, if I recall from you blogs, you didn't think an inboard track placement was worth the effort as the boat performs better bearing off a bit anyway? I think you also said you though a good size of a genoa would just overlap the shrouds; would that make it a 130? Maybe a 120? I plan to use the boat for some extended passages, so I'd sacrifice a bit of speed for a sail I could furl to a workable size in a blow without having to lose too much shape.

If I go the genoa route, the vertical lines you rigged I think would work fine with my railings, as the railings would be aft and inboard of the attachment point on the cabin top and thus the verticle line would prevent the windward line from falling behind the rail. Or rigging a line from the railing to the mast to the railing on the opposite side should work also. Both I should think would keep the line from falling behind the railing where it could get caught on a tack or jibe.

User avatar
thinwater
admiral
admiral
Posts: 1010
Joined: Mon Sep 22, 2008 8:08 am
Contact:

Re: Cabin top fiberglass thickness?

Postby thinwater » Wed May 04, 2016 8:45 pm

Backing the jib on the PDQ 32 or any boat with diamond wires on the mast is a bad idea; you will stretch the leach on the diamond wires. IMHO, backing the jib is almost NEVER a good idea. All backing does is stop the boat and eliminate all control.
* Speed
* Proper turning rate
* Ease traveler on new tack
* Release the genoa when it breaks
* Sheet the genoa in as fast as possible on the new tack
* Don't bring the main in until she is moving well

Yes, the keel mod helps a great deal. She is a different boat. Never goes into irons unless I intend that, and I can simply backer her out.

The inboard placement is essential to good windward performance and tacking. The point is not to over do it. I believe my placement is very close to optimum. Fore-aft would depend on the genny cut, of course.

I've never had a sheet get caught on the railing in a jibe. Only winches and hatches.

---

There are lots of little up-grades on Shoal Survivor, but 3 that really affect handling. The order in which I think they matter:
1. Inboard tracks. A lot of windward ability for the $$. Remember to reinforce the winches while the ceiling is down. Just do it, wish I had.
2. Keel mod. No more tacking problems, less leeway. wider "bucket" when sailing to windward. Very few $$, but some fiberglass skills help.
3. Transom stretch. A LOT of work and significant fiberglass skills. Minimal handling improvement, but I didn't expect much change. The motivation was improved dinghy access.
Writing full time since 2014.

http://sail-delmarva.blogspot.com/2017/ ... store.html
"Keeping a Cruising Boat for Peanuts"
"Singlehanded Sailing for the Coastal Sailor"
"Faster Cruising for the Coastal Sailor"

Iriemon
skipper
skipper
Posts: 52
Joined: Mon Apr 20, 2015 11:05 am

Re: Cabin top fiberglass thickness?

Postby Iriemon » Thu May 05, 2016 6:09 pm

Hmm. Here's what we did: Once the jib started luffing on a tack, we would ease the jib sheet until the clew was just to windward (on the new tack) of the mast. The jib would flap as the bow crossed the wind, but we'd hold it just for a couple second as the wind started coming abeam and back the jib, which would push the bow over, and then we'd release and trim in the jib on the new tack before it filled on the leeward side with the new tack. The result (it seemed to me) was a faster tack with less speed loss, versus the speed loss waiting for the bow to come over on momentum. Because the new tack angle was attained more quickly, you didn't have to bear off as much to get the boat speed back up. There was (it seemed to me) less loss of speed overall on the tack compared to waiting for the bow to slog across the tack on its own momentum. We had a 110 jib on the Island Spirit, this tactic would probably not work with a larger genny because the clew is farther aft. But I'll admit I'm no racer; and will defer to your much greater knowledge on the subject.

When I was talking about the sheet getting caught on the railing, I meant the new cabin top railings I'll be adding, not the outer deck railings.

Thanks for your comments. I think I will do your keel extensions mod (I'm pretty handy with fiberglass) next time we haul. I also liked your hull extensions a lot, which might even more benefit to me since I have the diesels on my PDQ and every bit of additional flotation (recognizing it is not a lot) would help, but that does seem like a much more involved job, so I'm not sure I'll figure the cost and hassle will be worth it.


Return to “PDQ Altair (PDQ 32) Forum”

Who is online

Users browsing this forum: No registered users and 4 guests