Old Style Trimarans - Crawlway Under Mast?

[troppo]

I have been checking out some old style trimarans - Piver Nimble 30 footers and Hedley Nicol Islander 32 footer. In the main cabin under the mast, there is a crawlway that goes into the forepeak. One tri had the head and a bed in the forepeak, another had the head, shower and storage.

Getting into the forepeak is a bit of a problem, in fact, impossible for my wife who has back trouble and can't crouch that low. The space is very low. It seems like a main support structure cuts across the cabin making for a difficult entry/exit to the forepeak.

The last tri I looked at, the height of the top of the crawl hole was higher than others I had looked at and cut in a semicircle. I wondered if it had been cut out higher after being built and if it compromised strength in any way. The design is very awkward for getting to and fro the forepeak so I don't reckon the designer was trying to be difficult but that it was essential for strengthening, which means change it with caution.

Anyway, that last tri, so I have just heard, has developed a crack near the mast and the owner is going to get a boatbuilder to assess it and work out how to strengthen up the mast supports.

It would make moving about in the boat so much easier if that space between the cabin and forepeak was higher.

Do you know how the height of the crawl space can be made higher without compromising integrity of the structure?

Here's some pics of tris on the 'net where you can see the area I am talking about:

Boat interior | Flickr - Photo Sharing!

See photo #5, the crawl way has a curtain half across the little opening.
Used Piver Nimble Trimaran for Sale | Yachts For Sale | Yachthub

PIVER TRIMARAN - Photo Viewer - REILLY AND ASSOCIATES

[Nemo55]

There is a method called sistering,(twinning) which a boat builder will use to reinforce the ribs in a boats hull,this would involve making a bulk head of the same dimensions and mounting it over the present bulkhead to reinforce said bulkhead, then one might cut the bulkhead opening higher i think.
Please consult a marine carpenter for what thickness would be appropriate.
G'Luck.

Originally Posted by troppo

I have been checking out some old style trimarans - Piver Nimble 30 footers and Hedley Nicol Islander 32 footer. In the main cabin under the mast, there is a crawlway that goes into the forepeak. One tri had the head and a bed in the forepeak, another had the head, shower and storage.

Getting into the forepeak is a bit of a problem, in fact, impossible for my wife who has back trouble and can't crouch that low. The space is very low. It seems like a main support structure cuts across the cabin making for a difficult entry/exit to the forepeak.

The last tri I looked at, the height of the top of the crawl hole was higher than others I had looked at and cut in a semicircle. I wondered if it had been cut out higher after being built and if it compromised strength in any way. The design is very awkward for getting to and fro the forepeak so I don't reckon the designer was trying to be difficult but that it was essential for strengthening, which means change it with caution.

Anyway, that last tri, so I have just heard, has developed a crack near the mast and the owner is going to get a boatbuilder to assess it and work out how to strengthen up the mast supports.

It would make moving about in the boat so much easier if that space between the cabin and forepeak was higher.

Do you know how the height of the crawl space can be made higher without compromising integrity of the structure?

Here's some pics of tris on the 'net where you can see the area I am talking about:

Boat interior | Flickr - Photo Sharing!

See photo #5, the crawl way has a curtain half across the little opening.
Used Piver Nimble Trimaran for Sale | Yachts For Sale | Yachthub

PIVER TRIMARAN - Photo Viewer - REILLY AND ASSOCIATES

[Nemo55]

P.S. Beautiful craft by the way... :-)

[FSMike]

Just be careful not to cut into the crossbeam, which runs the width of the boat and is a main support structure for the mast (and the entire boat for that matter).

[Kai Nui]

Originally Posted by FSMike

Just be careful not to cut into the crossbeam, which runs the width of the boat and is a main support structure for the mast (and the entire boat for that matter).

An therein lies the problem. The crossbeam is designed where it is. To reinforce and raise it would be a complete redesign of the boat. Likely more weight, definitely more windage and worse visibility from the cockpit.
We live with it. What we have found is you stay a little more flexible living aboard a boat that requires you to bend and flex all the time.
The attached pics are the roughed in interior and what we started with. No current shots of the installed composting toilet and finshed shower pan, but I will eventually take some.

[marshmat]

Troppo: No, I can't think of any easy way to enlarge that opening. That crossbeam is responsible for carrying the loads from the windward shrouds and the leeward outrigger into the main hull.

If it's a deal-breaker for you, so be it; the cost of modifying that crossbeam might be more than the boat is worth. Quirks like this are just part of the price you pay for choosing simple, inexpensive boats.

[troppo]

Excellent feedback, thank you folks.

I understand better now. That section is critical so I won't muck around with it. If I do want to try and gain a couple of inches of height, I would consult an expert. And then it might not be worth the cost. Cheaper for me to get and apply that book that tells how to build body flexibility.

That low area is one of those things that in my opinion, it is pointless putting up with if it can be changed and if it can not be altered then either I move on or adapt.

Funny thing, I used to roll my eyes at the sight of the old trimarans, thinking they were ancient and ugly. Now that I have been on a few of them, checking them out for maybe buying and thinking about cruising on one, I am changing my opinion. Now I think they are very interesting boats, as opposed to very odd, and I am keen to get one and try some cruising.

[Kai Nui]

There is allot to be said for keeping flexible. That specific feature of the old Pivers is not the only one that requires some climbing and bending. Just getting in and out of the bunks when half asleep is a feat all it's own. To work on the electrical on our boat requires climbing into a rather small area as does working on the engine.
The upside is I always feel better if I keep flexible.
And for what it's worth, I am a fairly big guy so that 4' walk through does take a little effort.
You may be able to gain a couple of inches by cutting into the floors and lowering the cabin sole. That said, the lower you go, the narrower it gets. I also found the bilge right under that section of cabin sole is ideal for the shower sump. Lowering the sole would eliminate that option.

[Kai Nui]

Oh yea, and the old Pivers are a blast to sail!