New Swim Platform

It's not even March, but we did not have winter this year in Philly. Went down to the boat, Tuesday, in Rock Hall, MD, where the staff of Swan Creek Marina will be commencing work on the engines - a story for another time.

I came back with the swim platform and the ladder down to the forepeak. It was all I could do to lift my end of the platform. About 3/4" thick, 12'-3/4" long, and 2'-4" wide. I measured it using a string line to take offsets to the transom edge, and anything else easy before I sawed it in half so that I could carry it into my basement shop. Turns out it's balsa cored. But, it's been the first thing to reach a piling a few to many times; the edges are cracked and the balsa is mush at every fastening.

The local fiberglass shop said it was not reliably repairable and they'd make a new one for $4500. I will use it as a pattern to make a new wood platform. Thinking of using Ipe or some other decking/boardwalk material. Maybe even one of the plastic plank products. Still mulling alternatives, of course, even thinking I could epoxy strips of decking to form the required curved profile. Straight pieces of would would require rather short lengths spanning to each bracket, which would not be nearly as stiff as continuous lumber.

Pics below. The rust stains are from the stainless steel brackets and fasteners.

Check out Plasteak.com for custom composite platforms..

Check out the swimstep dwhatty made a few years ago.

Trawler Forum - View Single Post - Your swim platform's utility

It's a beaut!

I made a new platform out of a new composite decking prior to last season. $700 and a long weekend. I like the results and it help up very well the first season.
I posted about it on another forum site. I can link to it if it is allowed. Can anyone chime in if it is OK?

Heckrotte: I can hardly believe what I'm hearing. With your woodwork skills, I figured you'd settle for nothing less than a custom made teak or better product. Another choice for no maintenance would be starboard with some reliefs cut or ground into it for traction. Heavy but easy to shape and machine while hard to damage with sufficient braketry.

mcgann454 said:

I made a new platform out of a new composite decking prior to last season. $700 and a long weekend. I like the results and it help up very well the first season.
I posted about it on another forum site. I can link to it if it is allowed. Can anyone chime in if it is OK?

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Here is a pic after one season:

mcgann454 said:

I posted about it on another forum site. I can link to it if it is allowed. Can anyone chime in if it is OK?

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That's fine.

FlyWright said:

That's fine.

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Thanks!
Here is the thread from last year when I started:

Building my own Swim Platform-new product - Cruisers & Sailing Forums

We used the plastic decking from Home Depot on our dive boat in the Virgin Islands. They recommend that stuff is not used underwater. Above water it lasted over four years before someone dropped a tank on it and broke one of the planks. This was getting daily use by divers and gear and out in the sun and wet all the time. We used the 2x6 planks. The original platform was wood and we did not want to have to treat it and everything else that wood requires in that environment. For the price you can't beat that stuff. Even has a fake wood grain on one side and can be cut with regular wood tools.

4500$ ? Wow it is covered with fiberglass or gold sheet?
IPE would be very strong but also very hard to machine and heavy.
Would be easy to build one using plywood sandwich with a polystirene core, and glazed with fiber glass, epoxy and finally painted, and will last long for a cost of less than 500$.

I don't have any of the pictures handy, so can't show you the result.
My boat came with a teak, slotted swim grid. Full width, but too narrow, especially with davits that reduced that width a further ~7". I left the original bronze supports in place, placed some 2"x6" oak on top, that expended their top surface length, then added 13" to the inside edge of the swimgrid. Since it was showing a little wear on top, I flipped it over to get "new " wood on top over its whole depth. The extra teak that I added, I milled from two planks. One was 14' of nominally 2 x 10, the other smaller, but used only for the shorter bits that space out the full length boards. I added them one at a time to the inside edge of the original SG, till I had added 13".
After placing the new SG on the oak, on the Bronze, it became clear quickly that the bronze couldn't handle the extra load, so I had new, taller and longer, and much stronger supports made up of SS. Those I fastened to the transom, drilling only above the waterline, and removed the bronze supports, filling each hole with a bolt bedded in 5200.
I subsequently used one of the bronze supports to make a pair of ladder hooks for a custom boarding ladder that I built out of Maple.

The teak cost then ( over 10 yrs ago) about $500, and was only enough to make 13" x 14'. I had all the tools already, so no extra cost there. I did this over several weeks in the winter so no time lost from my boating season.

The results: the SG looks like it came with the boat. It is wide enough to get around on safely, despite the davits biting a chunk out of the available space. The teak surface requires no maint whatsoever. It remains a natural non-skid. I can tie the dinghy through the slots anywhere along the length, I can tie the prawn traps to the SG and leave them there while travelling. All good, wouldn't have any other kind. And it was fun and rewarding to build.

I made a hot box out of stove pipe, and with a torpedo heater, got the Trex decking hot enough to bend it around the transom curve of my old boat...30' Carver with a ten foot beam.

My first attempt was to have the stove pipe suspended over a fire which heated the Trex up too much and trashed it. The stuff gets pretty bendy once it's hot.

Conall

does it maintain its new shape once its cooled ?

It's funny how scathing the others on that site were about your composite swim grid. It looks really good to me and none of their comments held water (sorry). Very nice result and so much more practical than wood or fibreglass.

It does stay in the newly formed shape after it cools down.

Conall

Xsbank said:

It's funny how scathing the others on that site were about your composite swim grid. It looks really good to me and none of their comments held water (sorry). Very nice result and so much more practical than wood or fibreglass.

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Yea, there were quite a few naysayers, but the older composite products would not have held up. The product I chose was new and is still untested. Bit of a gamble, but only a few dollars and time. Thanks for the comments.

Thanks for all the great replies!

I had forgotten about the strip-on-edge method to building up the width. Pretty silly of me when I recall my own floor grilles for the summer room. Dave's Teak and mcgann452's plastic look really good.

I don't much like walking barefoot on my floor grilles; the strips and gaps are 1/2" with relatively sharp edges. How do folks like walking barefoot on a surface with 1 1/8" strips and gaps? Besides ease of construction, the first 1 1/8" gap would be a dandy handhold I'd grab for when arriving by dinghy. OTOH, there's no reason that the spacer blocks have to be the same thickness as the decking strips. Hmmmm; gears turning!

Southeast Asian Teak is out-of-the-question expensive, particularly since local suppliers carry only random width rough stock so that buying to a width is already that much more expensive. About $35/bf. There is a local (Doylestown, PA) supplier of plantation-grown Teak from Central America; more reasonable price for lesser-quality and smaller pieces of stock. Ipe is about $5/lf of finished decking material. There are several other tropical hardwoods sold as decking at a lower price, but not stocked locally.

Pic of floor grille enclosed. White Oak. Intermediate blocks are actually crossmembers half-lapped from the bottom, and the top is recessed from the strips. Not yet urethaned in this pic.

DH
"I don't much like walking barefoot on my floor grilles; the strips and gaps are 1/2" with relatively sharp edges. How do folks like walking barefoot on a surface with 1 1/8" strips and gaps? Besides ease of construction, the first 1 1/8" gap would be a dandy handhold I'd grab for when arriving by dinghy. OTOH, there's no reason that the spacer blocks have to be the same thickness as the decking strips. Hmmmm; gears turning!"

You just need to walk the docks a bit to find the dimensions that work best.
I used a router to soften the edges after the SG was all laminated together. IIRC a 1/2" radius. The outside edge is original, about 4" solid, then the first slots, from there in, all 1 1/8 slots and slats, ending with a 1 1/8 final full length piece.

koliver, I think the comfort has a lot to do with the area of foot that is supported as compared with the gap width that is not supported. Thus, 2"x6" dock boards with the usual 3/8" or 1/2" of gap is comfortable (unless there are splinters or warped boards). As above, I wonder if the 1 1/8" boards and gaps, even if the board corners are eased, are comfortable. I think I'd drop an errant toe in a gap to the detriment of those within earshot. And those high heeled crew...

Ready, set...

I've bought plantation-grown Mahogany at a supply house in Ottsville PA, about an hour north of Philly. (This place has a small warehouse full of lovely stuff!) While they say it's genuine Mahogany, Swietenia macrophylla, it's not as red, nor as dense, nor as tightly-grained as the Honduras Mahogany that I'm more familiar with. It's sold for residential decking and is the usual decking size, about $3.90/lf.

I'm planning to rip the 5 1/2" wide stuff into roughly 1" widths and epoxy it back together bent to the shape of the old swim platform. The curved planks will end up about 5" wide.

The swim platform is about 12' long; sure makes the 8' shop worktable look small. I'll add temporary extensions to the table in order to affix blocks against which to bend and epoxy the new boards.

DHeckrotte said:

Ready, set...

I'm planning to rip the 5 1/2" wide stuff into roughly 1" widths and epoxy it back together bent to the shape of the old swim platform. The curved planks will end up about 5" wide.

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I'll be looking forward to watching this swimstep take shape.

FlyWright said:

I'll be looking forward to watching this swimstep take shape.

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Me too. Mr Deckrot is seriously impressive with timber work.
We used some red mahogany for window work,really heavy weight stuff for size of plank, must be a high density timber.

DHeckrott
Nice project! Are you relying only on epoxy to bond the strips and spacer blocks? Are you steaming the lumber?

Lots of pics as you move forward please

Thanks for letting us follow.

One, maybe stupid, question. Why to bend the strips instead of laminating a square board and then cut the platform shape in this square board?

Made a little progress over the last couple days: Revised the design several times, changing plank widths, end plank width, aftmost plank width, added handholds, added offset dimensions to transfer the shape to the worktable. Extended my 8' worktable to 12'. Ripped the Mahogany, and glued up the first plank. Progress will now be to glue up one plank a day for five more days.

Design constraints include: original outline, drainage, handholds, length of available stock. Still fretting whether I glue the whole thing into one piece or arrange that the planks will be free to move with wet and dry. Gut reaction is to glue it up. One alternative is to bolt the planks to crosspieces underneath; the negative to that, in my mind, is that those lapped joints would never dry and would rot prematurely.

Lou, the planks will be gapped for drainage and there will be no end grain running out along the edges. Thus very little end grain to absorb water or to provide splinters.

Very nicely done

As intended, glued the second plank today. And cleaned up the first plank.

Some of you know to expect 'spring back' when you laminate or steam bend wood to curves. That is, the newly bent/laminated member tends to straighten out a bit when released from its form. The first plank was clamped to blocks w/o allowing for spring back. Holding it at one end, it straightened about 3/4" in the 12' length to the other end; it bends readily back to the intended curve. Of course, the next five planks would require finished bends of larger radii than the first. Thus, I am able to glue all planks to the smaller radius of the first plank; saves me having to re-lay out, and relocate the clamping blocks. I will temporarily clamp each plank to its planned curve to prevent any gradual relaxation or creep.

Oh yes this is gonna be nice . I love all your work.I need to build one myself . We stock 6/4 African mahogany at work . I wonder how that would work .

I'm so jealous of you'se guys who know how to work with wood! That's an art form to me.

FlyWright said:

I'm so jealous of you'se guys who know how to work with wood! That's an art form to me.

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Need the right tools, which I don't have either.