narrowboat - steel vs fibreglass top

[gringogordo]

Hi,

 

I boat my boat a couple of years ago without much knowledge or investigation. There are two things about it which I kind of took for granted then but wondor about now (out of mild interest, I won't be offended by your views / the reality!). I'd be interested in real story / your views if you're happy to give them (!?)

 

1) It has a fibreglass top. I can't see the benefit to this, mobilesa and TV's etc seem to work fine in all steel shells and I can't see the weight difference being a big benefit ? The downsides of the fibreglass top as I see it are it is more fragile - I can't lay my semi naked body on the top while drinking a stella (an advantage maybe!) and it doesn't seal perfectly at the edges. It doesn't leak at the seal (especially with maintenance) but however much mantenance I do it is always damp around the gunwhales (at that level inside) during damp periods. Are fibreglass tops a failed experiment, a cheap build option or something else...?

 

2) The engine 'room' is under the decking at the back of the boat. It is permenantly wet. the bilge pump always leaves about 1/2 - 1 inch of water at the bottom. The seller told me this was normal and is even good as it prevents rust. I can't imagine its too bad as I've had a mechanic look at it once and he didn't scream but I think a lot of the better maintained boats have dry engine spaces and this surely must be better. Is there a right or wrong, or a good reason for allowing the bottom to be wet?

 

Cheers,

 

Ben.

[stuart]

A bilge pump will only pump out so much water, normally 1/2" is left. The key is to make sure no water can get into the engine bay in the first place. If youve got a cruiser type stern with a board to cover the engine, you will probably have some sort of drain or channels that should get rid of the rain water, see if they are blocked.

[Keeping Up]

A great many boats were built in this way, with steel hull and GRP top, in the late 60s and through the 70s. Our first boat, Thistle, was one of these, built (as probably more than half of them were) by Harborough Marine.

 

It was done as a cheap option, although in fact all-steel boats were relatively rare before 1970. The earliest few Harborough boats had a steel hull and a wooden top, but they soon changed to the use of GRP. Apart from price, one other advantage is that these were built using 'sandwich' boards consisting of 2 layers of GRP separated by a foam filler, which was a very good thermal insulator. Some other constructors used a simple wall of GRP, and they could be really cold. Another advantage is that they couldn't go rusty, but on the other hand they could (and did) tend to develop numerous leaks - the favourite places were at any joints between GRP sheets (obviously), at each handrail attachment (later Harborough boats had the mounting moulded into the roof and it leaked a lot less), around the windows, between the top and the hull, and anywhere else that a crack may develop or a screwhole may have been made. With the foam sandwich construction, as ours was, the water used to penetrate the outer skin and re-emerge up to 20 feet away, which made tracking the leaks a nightmare! Also with the different rates of expansion between GRP, steel, aluminium, and wood, any leaks that were cured would re-appear within a year, no matter how much sealer was used.

 

Most of the boats built around that era had what is termed a "wet bilge"; this may be what you have. This means that there were no internal separators between the front cockpit bilge, the cabin underfloor, or the engine bay (if you were lucky there may have been an oil barrier under the engine, but not all had them; of course, they are mandatory under the BSS now). The whole bottom of the boat was one giant bilge, which sloped from front to back so that any rainwater from the front cockpit had to run under the cabin floor to the rear, where it was joined by any rain that leaked through the back deck arrangement and could be pumped out - except that the pump always leaves a half-inch or so sloshing around in the engine area and under the rear cabin. On the way it may well have been joined by the sink and shower outlets! The advantages of this arrangement are (1) it's cheap and (2) the front cockpit floor can be as low as the cabin floor. But the disadvantages are that the area under the cabin is wet, smelly, and draughty (and goes rusty).

 

Do you know who built your boat and when?

 

Allan

 

(edited for smelling mis-takes)

Edited June 5, 2006 by Keeping Up

[gringogordo]

Thanks for that I think that definately descibes the bilge although its not smelly (the shower and sinks go straight to the cut though so this may be why). I'm not sure who built it as the paperwork just says 'unknown'! It was built in the late 70's though. Again, thank you - very helpful.

 

Ben.

[Liam]

Hi Gringogordo,

 

Do you have a picture of the boat which you can post up here? We may be able to tell you who built the boat.

[gringogordo]

Hi Gringogordo,

 

Do you have a picture of the boat which you can post up here? We may be able to tell you who built the boat.

 

 

oooo that could be emnbarrassing as she needs a good paint job..., but I'll try to get one.