Hull flex on GRP Enterprise

[saysomestuff]

Hi all,

Given that I have a bit of time on my hands I've started on my GRP Enterprise.

It was free with almost all parts incl. sails so as you can imagine it needs a bit of work.

One (rather dull) question I have is regarding the amount of flex in the hull. Now the main part of the floor is very soft as the timber ribs running longitudinally are rotten, not too concerned about that as it's a relatively simple glass job.

What I'm concerned about is how easy it is to deflect the sides nearer the bow, particularly across the first chine which one would assume would be a pretty rigid area.

Anyway, video is linked below, can any of you fine members help put my mind at ease?

Cole.

 

[Catalina36]

Glass in a bit of foam if you're worried.

 

[lw395]

How old is the boat?
Early GRP versions of ply boats like Ents and Solos were quite hard to build down to weight. They are very thing in places, and the panel shapes mean they flex.
It gets worse as they get older, but it's not really a problem, just means they are a bit slower for racing.
Modern ones will be foam sandwich and stiffer than plywood.
Avoid excess weight as much as you can.

 

[michael_w]

Early GRP Ents are slower than a slow thing. I suspect the stringers inside the bow tank have come adrift.

Not worth bothering with IMHO. Why do you think someone gave it away?

 

[saysomestuff]

Glass in a bit of foam if you're worried.

I suspect the stringers inside the bow tank have come adrift.

Avoid excess weight as much as you can.

Thanks, this is useful, I was reluctant to open up the front buoyancy chamber but I think I'm going to need to have a look to see if there's anything meant to be re-attached in there rather than adding new weight.

How old is the boat?

it's sail number 13583 so assuming quite old, I think over 50k sold now.

Not worth bothering with IMHO. Why do you think someone gave it away?

I see what you mean but I live less than half a mile from the beach. So I want a small bermuda rig for messing about on calm days when I don't have a the tide/time/inclination to take the yacht off the mooring. Free is free, I have loads of spare fiberglass bits so the decision isn't really best vs. better - it's actually slow boat vs. no boat.

 

[lw395]

An Ent is not really a slow boat. They go OK in light weather. A great boat for teaching, being more responsive than some others.
And a low cost boat is just what you want on a beach.

 

[Bobc]

Stick a couple of layers of 300g woven rovings inside and it'll be fine for mucking about with.

 

[saysomestuff]

Thanks all for your comments. I bit the bullet and opened the front buoyancy tank and surprise surprise, was greeted by rotten plywood strips all collected in the bottom.

I'm going to glass some narrow timber strips inside there just to reduce the likelihood of the bow caving in as I'll probably end up "parking" on the odd beach or bay.

Final question: it seems a bit pointless glassing over the timber strips in the floor of the boat when I renew them. They were certainly not encased in the sole for structural reasons, literally held in by a single crispy layer so am I just as well to epoxy the new surface stringers to the newly prepared flat floor and just whack a bit of varnish on them?

 

[lw395]

You can epoxy wood to the flat panel and the wood will add stiffness.
You can put glass tape/mat/cloth up the side of the wood, to form a grp rib which will add stiffness.
You can use cardboard as a temporary former for the grp rib instead of the wood.
You can glass over a 'paper rope' or similar to form a box section/tubular rib.

It's not critical, it's a balance between work, weight and stiffness.

Ply strips, edge-on to the panel, secured with a fillet of epoxy would seem a reasonably cost effective and not too heavy solution?
Just varnishing any exposed wood will be OK if the tank is kept reasonably dry. I'd epoxy coat any bits where water is likely to gather.

 

[michael_w]

The strips are there to add stiffness to what is a very flat area. My plywood Dave Ovington built Ent had them too,

 

[saysomestuff]

It's not critical, it's a balance between work, weight and stiffness.

Thanks, yeah that's the crux of it really. The main job is the interior sole as it is such a large flat space as Micheal mentions, so some small reinforcement jobs in the bow tank make sense while I'm at it.

The strips are there to add stiffness to what is a very flat area. My plywood Dave Ovington built Ent had them too,

Absolutely, the sole is very weak and flexible (and probably about 20% filler at this point!), it's the main job on the cards.

I have a load of oak skirting offcuts so should have enough to do a decent job of replacing them all.

I'm thinking now though that the most efficient means to get it done would probably be to just take off gelcoat from the sole, frame the hull to the proper shape, epoxy the strips to the bare "cockpit" sole, then put a layer or two of combi mat over the whole lot. That should save me needing a layer on the outside of the hull then - I'm sort of thinking it'll work like an arch in that the new layers in the sole will resist deformation as they'll be under compression to keep the curve.

 

[Gixer]

I used to own E15 in the 2000's, I wonder what happened to that??