10 ` GRP Dinghy carrying capacity ?

waynes world

Well-known member
Joined
7 May 2011
Messages
1,567
Location
Manchester
Visit site
Hi all.

I have a Dinghy mould that i intend to knock a few out and was wondering if anybody has an idea of what the load capacity would be of a 10` x 4 ` GRP Dinghy. I can get a pic of the mould of need be to show the shape roughly.

Thanks Captain Faffer :)
 

lw395

Well-known member
Joined
16 May 2007
Messages
41,951
Visit site
Dependson the shape.
Anything from 1 child to about 3 adults?
If it has deep topsides and plenty of rocker, you can load it up without the transom being deep in the water and without it being swamped by small waves. As soon s the transom is more than an inch or two immersed, it will have the drag factor of a bingo hall.
4ft sounds quite narrow, but if it's 4ft at the waterline it should be fairly stable.
 

Daydream believer

Well-known member
Joined
6 Oct 2012
Messages
20,068
Location
Southminster, essex
Visit site
Do you intend to sell them?
Are you actually allowed to ?- Although if we are no longer in the EU that will not be a problem. However, I thought that even tenders had to comply with some form of regulation. Rather like yachts.

Is that correct?

If HMG have not changed the rules,( only copied them to UK law) you could run foul of them if someone had an accident
 

waynes world

Well-known member
Joined
7 May 2011
Messages
1,567
Location
Manchester
Visit site
I could sell them yes but they would be second hand used items , but no plans as yet

And will be used on canals, so sea use.



Pics of the mould to give a better idea

tn_20170205_133127.jpg



tn_20170205_131949.jpg
 

VicS

Well-known member
Joined
13 Jul 2002
Messages
48,364
Visit site

johnalison

Well-known member
Joined
14 Feb 2007
Messages
39,840
Location
Essex
Visit site
A 10ft dinghy will possibly still be floating with eight people on board, but it won't be safe outside the local boating pond. We normally carried two in our 8ft pram. Just occasionally we would take three, but that was the limit, in calm water. A 10ft dinghy should take three fairly easily, but four only in very limitd conditions.
 

Daydream believer

Well-known member
Joined
6 Oct 2012
Messages
20,068
Location
Southminster, essex
Visit site
One also has to factor in for stability. The craft may displace .25 M3 of water OK ( 250KG) but it could roll over quite easily.
I imaging a semicircular shape would be dangerous. A rectangular shape possible better.
Your craft would need to be a shape somewhere between the two, to make it "rowable" & stable.
A person stepping into it will place weight on the side. This will govern some of its weight carrying capability as well as central load displacement.
If you have a mould you might ask yourself why you have it & its history?
ie. Was it bankrupt stock, or a failure sold off cheap etc

Then work out how much it is going to cost in time, materials, inc GRP, wood , accessories etc & ask yourself if it is better to fill it with earth & grow plants in it

You would be better going to a marina where there are loads of dumped old dinghies ( they had about 20 at Bradwell a few years ago) taking them off their hands, repairing & cleaning them up & flogging them
 
Last edited:

ghostlymoron

Well-known member
Joined
9 Apr 2005
Messages
9,889
Location
Shropshire
Visit site
Our 10' minipram carries two safely but has carried four in flat water very cautiously for a short distance. It is hard chined and therefore has some form stability.
 

PetiteFleur

Well-known member
Joined
29 Feb 2008
Messages
5,043
Location
Suffolk
Visit site
Dependant on it's shape I would have thought it was capable of carrying 4 adults in calm water. My 8' tubby dinghy has carried 4 adults on a calm day up river to my mooring. A few years back I went to do some work on the boat whilst on it's mooring but decided it was too rough for my dinghy solo - however a fellow boater offered to take me in his 10' dinghy and I was surprised at the difference in stability. It was much safer in those conditions.
 

burgundyben

Well-known member
Joined
28 Nov 2002
Messages
7,486
Location
Niton Radio
Visit site
I once considered building an ultralight tender out of kevlar sandwich, not much point building what you can buy secondhand if you keep your eyes open.

I'd love a 10ft dinghy, built in carbon/kevlar/foam core infused hull, ultra light.

I have an old Avon sportboat and I plan to make some ultra light floorboards for it.
 

sarabande

Well-known member
Joined
6 May 2005
Messages
36,001
Visit site
Sorry, but that mould looks as if it will produce a very rolly dinghy. Perhaps deeper keels might help, but if you are after good stability and easy to row, I wouldn't start from there.

And unless you have loads of very cheap epoxy/matting, it is going to be an expensive dinghy for final fit out with rowlocks, oars, towing point..

Also, I think there's recent legislation about dinghies having to be provided with two buoyancy compartments.
 

Medway Matt

Active member
Joined
17 Sep 2015
Messages
151
Visit site
Sorry, but that mould looks as if it will produce a very rolly dinghy. Perhaps deeper keels might help, but if you are after good stability and easy to row, I wouldn't start from there.

And unless you have loads of very cheap epoxy/matting, it is going to be an expensive dinghy for final fit out with rowlocks, oars, towing point..

How would deeper keels help with stability, unless filled with lead? And why use epoxy resin when polyester would be perfectly adequate?
 
Top