Gin
Well-Known Member
Re: Guidance on O/Board size for a 12\'6\" Foreland Dingy
Yeah but you can get the Tohatsu for £349 plus £5 delivery!
Yeah but you can get the Tohatsu for £349 plus £5 delivery!
Guidance on O/Board size for a 12'6" Foreland Dingy
- Thread starter PIPSQUEAK
- Start date
kengill
Well-Known Member
Re: Guidance on O/Board size for a 12\'6\" Foreland Dingy
My calculations suggest it has sufficient buoyancy to support a pair of 200hp honda four stroke with SWIMBO sitting on the front. All it would take is a little time and fibreglass and resin, a bit here or there with some marine ply to re-inforce the transom, a hydrofoil or two and it can be converted into a high speed craft for getting the fish back really fresh! In your dreams Buddy!!!!
I've towed too many mobos back to the marina, with my sailing yacht, after their (single) engine failed.
And I've also been towed back by a mobo after the engine, the tender out board and the wind failed!
/forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif
My calculations suggest it has sufficient buoyancy to support a pair of 200hp honda four stroke with SWIMBO sitting on the front. All it would take is a little time and fibreglass and resin, a bit here or there with some marine ply to re-inforce the transom, a hydrofoil or two and it can be converted into a high speed craft for getting the fish back really fresh! In your dreams Buddy!!!!
I've towed too many mobos back to the marina, with my sailing yacht, after their (single) engine failed.
And I've also been towed back by a mobo after the engine, the tender out board and the wind failed!
/forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif
VicS
Well-Known Member
Re: Guidance on O/Board size for a 12\'6\" Foreland Dingy
[ QUOTE ]
To be a little serious, a Seagull Forty Featherweight, would be ideal in my opinion,
[/ QUOTE ] I am going to diagree. I use one for my tender which is somewhere between 7 & 8ft and very light (I can pick it up and carry it and load onto the roof rack unaided) I usually run it full throttle to go out to the mooring.
I have a 40 + that I used to use on my Mirror 10. I think a 40+ might just be enough but against any wind or tide a Century may be better.
[ QUOTE ]
To be a little serious, a Seagull Forty Featherweight, would be ideal in my opinion,
[/ QUOTE ] I am going to diagree. I use one for my tender which is somewhere between 7 & 8ft and very light (I can pick it up and carry it and load onto the roof rack unaided) I usually run it full throttle to go out to the mooring.
I have a 40 + that I used to use on my Mirror 10. I think a 40+ might just be enough but against any wind or tide a Century may be better.
VicS
Well-Known Member
Re: Guidance on O/Board size for a 12\'6\" Foreland Dingy
[ QUOTE ]
Also could someone explain the difference (physical and peformance) between long, standard and short shafted engines
[/ QUOTE ]
Generally, although it varies a bit, standard shaft models are approx 15", long shaft about 20", extra long about 25".
That measurement is the distance from the top of the transom or mounting bracket to the water level. So measure that and choose your "shaft length" accordingly. It is more important to know it in inches (or mm) than whether the maker classes it short, standard or long.
If you use a longer shafter length than necessary the exhaust outlet may be so deep that the back pressure makes starting difficult. On the other hand if the "shaft length" is too short the water pump will lose suction and in a bit of a chop the propeller may keep coming out of the water. Then you get absolutely nowhere. It is better therefore to go longer rather than shorter.
Some small engines have no clutch or gears. A clutch is very useful but they can often be turned in their mounting through 180 degrees to go astern.
You also need to consider if a small integral fuel tank will give you sufficient range or whether you need a model with a separate tank.
[ QUOTE ]
Also could someone explain the difference (physical and peformance) between long, standard and short shafted engines
[/ QUOTE ]
Generally, although it varies a bit, standard shaft models are approx 15", long shaft about 20", extra long about 25".
That measurement is the distance from the top of the transom or mounting bracket to the water level. So measure that and choose your "shaft length" accordingly. It is more important to know it in inches (or mm) than whether the maker classes it short, standard or long.
If you use a longer shafter length than necessary the exhaust outlet may be so deep that the back pressure makes starting difficult. On the other hand if the "shaft length" is too short the water pump will lose suction and in a bit of a chop the propeller may keep coming out of the water. Then you get absolutely nowhere. It is better therefore to go longer rather than shorter.
Some small engines have no clutch or gears. A clutch is very useful but they can often be turned in their mounting through 180 degrees to go astern.
You also need to consider if a small integral fuel tank will give you sufficient range or whether you need a model with a separate tank.
richardabeattie
Well-Known Member
Re: Guidance on O/Board size for a 12\'6\" Foreland Dingy
Ah but which seagull and how exactly do you catch and harness them?
Ah but which seagull and how exactly do you catch and harness them?
richardabeattie
Well-Known Member
Re: Guidance on O/Board size for a 12\'6\" Foreland Dingy
Vitalman this is a tiny sailing dinghy not a motor boat. It has a mast and little wisps of cloth and two wooden things to poke in the water and it is in sight of land. Don't make the poor bloke carry two engines as well.
Vitalman this is a tiny sailing dinghy not a motor boat. It has a mast and little wisps of cloth and two wooden things to poke in the water and it is in sight of land. Don't make the poor bloke carry two engines as well.
PIPSQUEAK
New Member
Re: Guidance on O/Board size for a 12\'6\" Foreland Dingy
No it is not a sailing dingy and I have inherited a new pair of oars, still in their wrapping and since, 45 years ago, my mate's dad, when he bought him a similar sized boat, insisted that we both learn to row before he provided the outboard (5Hp evinrood). I can row - well I presuppose I can still row - it must be a bit like riding a bike - once learned never forgotten. The intended use, once all the woodwork has been replaced, is to transport me back to my childhood when the whole summer holidays were spent digging bait at low water followed by a day fishing - shear tranquil bliss interspersed with the excitement in anticipation of actually finding if one's assessment of what was on the end of the line was correct.
They were great summers, very similar to what we are experiencing now that the disturbances caused by testing H bombs has long gone- hot with thundery interludes, swimming from April to Otober. I cant wait to see if things have stayed the same. One change is that there is more lug available on my beach.
The only spare parts we took were shear pins, pull cord and spark plug. Many a time the latter was dropped overboard in a heavy swell. I can still swim a kilometer or so without too much lost breath and don't anticipate ventureing any more than that from the shore.
However the tide of the outfall, always good for hooking fish, at times runs at 7 or 8 knots and recollect that the evinrood would struggle against the tide and would force us inshore when the spare cotters came in handy so would prefer something perhaps a little stronger. Hovever one reply mentioned "hull speed" of 4 to 5 knots. Surely the boat's speed is proportional to the engine size with the structural strength of the boat as a limiting factor hence the request for how to determine such matters or is it simply experience?
Thanks to everyone for your responses. They are all very helpfull.
No it is not a sailing dingy and I have inherited a new pair of oars, still in their wrapping and since, 45 years ago, my mate's dad, when he bought him a similar sized boat, insisted that we both learn to row before he provided the outboard (5Hp evinrood). I can row - well I presuppose I can still row - it must be a bit like riding a bike - once learned never forgotten. The intended use, once all the woodwork has been replaced, is to transport me back to my childhood when the whole summer holidays were spent digging bait at low water followed by a day fishing - shear tranquil bliss interspersed with the excitement in anticipation of actually finding if one's assessment of what was on the end of the line was correct.
They were great summers, very similar to what we are experiencing now that the disturbances caused by testing H bombs has long gone- hot with thundery interludes, swimming from April to Otober. I cant wait to see if things have stayed the same. One change is that there is more lug available on my beach.
The only spare parts we took were shear pins, pull cord and spark plug. Many a time the latter was dropped overboard in a heavy swell. I can still swim a kilometer or so without too much lost breath and don't anticipate ventureing any more than that from the shore.
However the tide of the outfall, always good for hooking fish, at times runs at 7 or 8 knots and recollect that the evinrood would struggle against the tide and would force us inshore when the spare cotters came in handy so would prefer something perhaps a little stronger. Hovever one reply mentioned "hull speed" of 4 to 5 knots. Surely the boat's speed is proportional to the engine size with the structural strength of the boat as a limiting factor hence the request for how to determine such matters or is it simply experience?
Thanks to everyone for your responses. They are all very helpfull.
Lakesailor
Well-Known Member
Re: Guidance on O/Board size for a 12\'6\" Foreland Dingy
Nope. The hull speed of a craft is determined by it's length. It creates a bow wave and the stern sits in the trough. To climb out of it's wave needs a hull shape that encourages it to plane. This requires lots of power. However a round-bilged boat will not plane unless supplied with extreme amounts of power, and then may simply bury itself under it's bow wave.
There are others on here here who know a ot more about it than I do. suffice to say you won't make headway against an 8 knot tide in your boat. You need to plan your trips around the tidal flow.
Nope. The hull speed of a craft is determined by it's length. It creates a bow wave and the stern sits in the trough. To climb out of it's wave needs a hull shape that encourages it to plane. This requires lots of power. However a round-bilged boat will not plane unless supplied with extreme amounts of power, and then may simply bury itself under it's bow wave.
There are others on here here who know a ot more about it than I do. suffice to say you won't make headway against an 8 knot tide in your boat. You need to plan your trips around the tidal flow.
mikefleetwood
Well-Known Member
Re: Guidance on O/Board size for a 12\'6\" Foreland Dingy
I still stick with my original (tounge in cheek) suggestion. A small Seagull will work perfectly for you. Or, any other small o/b you can get cheaply - but for the money you will find Seagull more reliable. As for horsepower, anything between 2 and 8 will be plenty. As has been explained by others, no amount of horsepower is going to make your dinghy outrun 8kt of tide, so consult the tables before going out! When you've only got a 12' boat, the last thing you want is to clutter it up with a spare o/b - so forget that particular advise. Spend the money on lifejackets and flares (I see you've already got oars). Lots of people don't bother with safety gear with a small dinghy, but it is SO easy to tip over or fall out when fishing, etc. (yes, I've done it, and it's not funny!).
I use a 10' dinghy (it's a bit small, 12' would be better, but heavier to drag up the beach) with Seagull/oars for local fishing, never more than a couple of miles from home, just like you are planning - ideal.
I still stick with my original (tounge in cheek) suggestion. A small Seagull will work perfectly for you. Or, any other small o/b you can get cheaply - but for the money you will find Seagull more reliable. As for horsepower, anything between 2 and 8 will be plenty. As has been explained by others, no amount of horsepower is going to make your dinghy outrun 8kt of tide, so consult the tables before going out! When you've only got a 12' boat, the last thing you want is to clutter it up with a spare o/b - so forget that particular advise. Spend the money on lifejackets and flares (I see you've already got oars). Lots of people don't bother with safety gear with a small dinghy, but it is SO easy to tip over or fall out when fishing, etc. (yes, I've done it, and it's not funny!).
I use a 10' dinghy (it's a bit small, 12' would be better, but heavier to drag up the beach) with Seagull/oars for local fishing, never more than a couple of miles from home, just like you are planning - ideal.
VicS
Well-Known Member
Re: Guidance on O/Board size for a 12\'6\" Foreland Dingy
[ QUOTE ]
The hull speed of a craft is determined by it's length
[/ QUOTE ] Quite right. Although it varies a bit according to the design of the boat, for small craft of normal shape the maximum speed, in knots, is approximately 1.5 times the square root of the waterline length in feet.
Re the discussions about Seagulls I stand by what I said about the Featherweight 9aka 40 minus). which only produces about 1.5 hp. It won't be big enough. It was also only made with a short shaft, about 12".
According to the S.O.S. website the powers of all the models are [ QUOTE ]
Forty minus :- 1 to 1.5 hp, later as 1 to 2 hp, or later still, (before being called the 45), just 2hp.
Forty Plus (direct drive):- 1.5 to 2.5 hp, later as 2 to 3 hp
Forty Plus, Clutch Drive:- 3hp
The Century:- 4hp ( Villiers carb.)
Silver Century, :- 3 to 4.5hp (Amal carbed version of the Century.)
Century Plus, clutch drive 4.5hp.
Silver Century Plus, clutch drive, 4 to 5.5, later 5 hp.
Model 102, Direct or Clutch drive:- 3.5 to 4 hp
Model 102 Plus Clutch drive:-3.5 to 5 hp
Model 170:- hp not given as after 1980 Trades Descriptions Act! believed to be 7.5 hp!
Model 125:- again not given, but approx 5 hp.
QB curlew:- 4hp
QB Osprey:- 5hp
QB Kingfisher:- 6hp.
[/ QUOTE ]
[ QUOTE ]
The hull speed of a craft is determined by it's length
[/ QUOTE ] Quite right. Although it varies a bit according to the design of the boat, for small craft of normal shape the maximum speed, in knots, is approximately 1.5 times the square root of the waterline length in feet.
Re the discussions about Seagulls I stand by what I said about the Featherweight 9aka 40 minus). which only produces about 1.5 hp. It won't be big enough. It was also only made with a short shaft, about 12".
According to the S.O.S. website the powers of all the models are [ QUOTE ]
Forty minus :- 1 to 1.5 hp, later as 1 to 2 hp, or later still, (before being called the 45), just 2hp.
Forty Plus (direct drive):- 1.5 to 2.5 hp, later as 2 to 3 hp
Forty Plus, Clutch Drive:- 3hp
The Century:- 4hp ( Villiers carb.)
Silver Century, :- 3 to 4.5hp (Amal carbed version of the Century.)
Century Plus, clutch drive 4.5hp.
Silver Century Plus, clutch drive, 4 to 5.5, later 5 hp.
Model 102, Direct or Clutch drive:- 3.5 to 4 hp
Model 102 Plus Clutch drive:-3.5 to 5 hp
Model 170:- hp not given as after 1980 Trades Descriptions Act! believed to be 7.5 hp!
Model 125:- again not given, but approx 5 hp.
QB curlew:- 4hp
QB Osprey:- 5hp
QB Kingfisher:- 6hp.
[/ QUOTE ]
mikefleetwood
Well-Known Member
Re: Guidance on O/Board size for a 12\'6\" Foreland Dingy
I think mine's a 40+. Maybe something a little bigger would be better for 12', but I suspect hull speed would still be the limiting factor even with a 40+.
I think mine's a 40+. Maybe something a little bigger would be better for 12', but I suspect hull speed would still be the limiting factor even with a 40+.