Help? GRP Hull Structure Integrity

[Blackbird]

Could anyone advise me on whether or not I can strip out the GRP fairings (my top circle in the pic marks the ones I want to dispense with) that make up the V-berth on a Westerly 22 without compromising the strength of the hull. I want to dispense with the lockers and the berths in the fore section - make it open plan as it were. People often cut holes in these fairings to give easy access (I've circled an example lower right in the pic) but I am slightly worried that stripping them out (after all, they are built into to the hull in construction) could affect the rigidity of yacht. And if I shouldn't strip them out completely how far can I go to open the up?

Would appreciate some comments from the learned members.

Thanks, Jay

[boatpoker]

Blackbird : That GRP (you must be English) fairing is actually a part of a structural liner. This liner takes the place of and performs the same functions as floor members and frames. Not the kind of thing to be modified without consulting an NA with FRP .... sorry ..... GRP experience

[CalebD]

I am not a NA (Naval Architect) by any means so take what I say with a grain of salt.

In my ancient (1967) Tartan 27' there are storage compartments under the Vee berths on both the port and stbd sides where your drawing indicates you wan to 'make them open plan'. We have a water tank">fresh water tank forward under the Vee berth so no storage locker there. Our openings on both sides are approx. 6" x 12" and have wooden (teak?) insert panels to cover them.
There is limited storage space even on our slightly bigger boat but what is nice is that there is access to it. Another option would be to cut a section of the horizontal Vee berth run that provided access to below with a removable section that simply pulls up and lies flat in it's cutout when the Vee berth cushions are on top of it.
You did not say what year your Westerly was from but I have gathered that they are pretty stoutly built boats. If you were worried about reducing your boats structural integrity you could always add some extra members or 'sisters' to help with supplying rigidity.
Think about a load bearing wall that you want to add a doorway to. Now think about the same thing on a boat that takes much more stress then your average house. In a house a carpenter would add a 'header' to any load bearing wall to distribute the load to the sides of the new opening. This may mean attaching a structural framework to support your new cut away sections for your 'open plan'.
Frankly, I am not a big fan of open sections into the bilge as you seem to want to do. Once the boat gets up on a heel everything will spill out from there so the horizontal access idea is much better. You still may want to add some support to your cut out section(s) that are horizontal and not vertical.
Your boat has 2 keels right?

[Blackbird]

Thanks. Near enough: Scottish not English. We share the same island but in terms of how we are we could be from different planets. As people live their lives, so they are. Well enough of that. So the liners are part of the frame. The point about these little baby yachts is they are built like the proverbial brick shithouse and I thought I could play around with them a bit. The V-berth has been colonised by my dog and, except for him, is virtually a dead area and I wanted to turn the section into a desk. There is plenty of storage elsewhere (it has an O/B so there is masses of room under the cockpit and with the lockers under the other two quarter berths). The implication of what you saying is that the owner is always lumbered with what the layout of the manufacturor unless he spends an arm an leg on experts. There must be a way, however, of compensating for what the built-in liners contribute to structure by expoxying in some adapted stringers.

But thanks anyway for marking my card on the issue.

[boatpoker]

Forgive the insult. If I'd known you were a fellow Scot I would have known you were capable of making structural changes

[Blackbird]

I really appreciate you reply. Thanks. What you describe on the Tartan is virtually identical to the Westerly 22 and seems to be the template for all these small cruiser yachts. My problem at the moment is that this area is virtually dead except for the dog who sits on it. The fore locker locker is useful for a water tank (I've arrowed it in yellow) but the one aft of it (I put a cross in black on the facing liner and the wooden access flap) is usually where they install a marine WC. The mini-bulkhead that separates these two lockers I didn't intend to touch (I have marked it roughly in red). The bits I wanted to strip out were those liners aft of it (I've marked those in blue). I wanted to build in a work station as it is the perfect height, if one is sitting down roughly where the WC locker is. I planned on putting in a desk and shelving, so really what I would have to do is also as you suggest epoxy in some sisters or ribs or what-have-you. Any ideas of how I can find out what kind of sister frame would suffice as compensation?

[Blackbird]

We were all bought up on the Clyde, which is why I'm holding out the suggestion box. But I'll get there.

[CalebD]

I'm no Naval Architect but I am part Scotch Irish - hence the Tartan.

You could make your extra support sisters/ribs out of wood if you covered it in GRP. Perhaps a more ideal solution would be to use the sections of GRP that you cut out and shape them so they could be used as sisters/ribs and 'header' (along the top of the opening). Keeping everything made of the same material is preferable because of expansion/contraction due to varying temperatures. Wood also has a way of rotting on a sail boat if it gets wet.
Slainte.

[Blackbird]

I wouldn't have thought of that. Thanks. I'd have just taken the chain saw to it.

You should watch the Big Yin's Tour of Scotland. It is quite old now but it ages well. It makes you want to "stay awhile with your own ones".

[sailvayu]

Beyond structure issues here there is something few people consider when doing modifications like this is resale value. You will likely take away a large part of the value of the boat by doing what you are thinking. I would try to figure a way to get what you want so that it is removable. I see lots of folks do things like that and then wonder why they cannot sell the boat. And even if you do not plan to sell now things change. Think about it before you get the chain saw out.

Fair Winds

[CalebD]

Sailvayu (Wayne) if of course correct. That is why I suggested making some removable panels on top (horizontal surface) of the compartments you would like to open up rather then in the vertical (most of the time) sides. I am certain that this would be considered less of an invasive change by most prospective buyers which would easily hide under a Vee berth cushion.
It is your boat and you get to decide what you want to do so good luck.

[Blackbird]

>Beyond structure issues here there is something few people consider when doing modifications like this is resale value. You will likely take away a large part of the value of the boat by doing what you are thinking. I would try to figure a way to get what you want so that it is removable. I see lots of folks do things like that and then wonder why they cannot sell the boat. And even if you do not plan to sell now things change. Think about it before you get the chain saw out.>

Thanks. Once it is in my head I always find it difficult to resist the chain saw. Seriously (well, for me anyway), though, I did factor in the resale issue. She is an old GRP bird ('67, W22)...tough and dry but she can probably feel the darkness in. I know I can. In actual fact, I looked at a lot of these pocket cruiser yachts and the manufacturers seem obsessed with providing extra berths that are never used. They become cluttered up with stuff over time and the V-berth in the forepeak often end up looking like junk yards. Open planing this section will probably make the interior look airier.

[Blackbird]

>Sailvayu (Wayne) if of course correct. That is why I suggested making some removable panels on top (horizontal surface) of the compartments you would like to open up rather then in the vertical (most of the time) sides. I am certain that this would be considered less of an invasive change by most prospective buyers which would easily hide under a Vee berth cushion. It is your boat and you get to decide what you want to do so good luck.

I think at her age she will be the better for a little plastic surgery. My only real issue is how to use the gash liners (I have to thank boatpoker for that terms, BTW) to such effect that I compensate for whatever function they serve as floor members and frames.