Partial roof on a 14ft f/glass speedboat

Discussion in 'Boat Design' started by valvebounce, Nov 8, 2019 at 10:20 AM.

  1. valvebounce
    Joined: Dec 2010
    Posts: 496
    Likes: 10, Points: 18, Legacy Rep: 124
    Location: manchester uk

    valvebounce Senior Member

    My boat is an open boat,I've converted it for sea fishing,removed the rear seats for more fishing space,
    and altered the transom to take a longshaft outboard,I made the transom so that the cavity plate is 2"
    below the hull at the stern for more steering stability in a turn and rough water.
    I would like to put a front panel with a windscreen on it,(20mm GRP jig sawed out)
    Then put a roof on it extending back past the front seats.I would only need the height to be enough for comfort when sitting in the seats.The idea is to get out of the rain.I will probably need rear pillars at back of the roof.I don't need filled in sides,just the screen and roof.
    The boat planes well with very little spray from the bow.It has a pointed bow that reduces to almost flat at the stern.
    I need the cover to keep my fishfinder and ship to shore radio out of the weather.
    The boat is sturdy and very stable,and rides well.The Freeboard is about 2ft+ safety rails of 6".
    Has anyone attempted a similar project?
    Any suggestions will be gratefully received.
    Valvebounce (Manchester UK)
     
  2. bajansailor
    Joined: Oct 2007
    Posts: 351
    Likes: 49, Points: 28, Legacy Rep: 37
    Location: Barbados

    bajansailor Marine Surveyor

    Hello VB, can you perhaps post a photo of your boat?
    Do you steer the engine with a tiller, or have you got a console with a steering wheel?
    If a console, is it a centre or side mounted console?
    If you have a console, then it might be easiest to just put a windscreen on it, and have a collapsible bimini type of awning on S/S tubular hoops over the console and cockpit to give you some shelter from the rain?
     
  3. valvebounce
    Joined: Dec 2010
    Posts: 496
    Likes: 10, Points: 18, Legacy Rep: 124
    Location: manchester uk

    valvebounce Senior Member

    Hello BJS,I'll have to sort a photo out.
    The boat has a steering wheel on the right of the dashboard.I would have to fix the screen to the hood on the bow of the boat just in front of the steering wheel and passenger seat.The boat is kept outside,and the weather here in the UK is wet
    rather than sunny.The boat drains ok with the bow wound up on the trailer with the bung out at the stern.
    I've considered Bimini tops,but I don't think they would last long.
    My idea was to have a windscreen frame,with a fibreglass roof.(I have a sheet of fibreglass off the bow hood/bonnet off another boat)I intended to fibreglass it to the boat and windscreen frame.
    I seem to have lost the pics of my boat,I'll take a couple more and put them up.
    The boat is an English Broome Gemini speed boat from the 70's/80's.
     
  4. bajansailor
    Joined: Oct 2007
    Posts: 351
    Likes: 49, Points: 28, Legacy Rep: 37
    Location: Barbados

    bajansailor Marine Surveyor

    Here is a Broom Gemini for sale - they say that she is 3.93 m / approx 13' - is she similar to your boat?
    Broom Gemini For Sale, 3.93m, 1981 https://norfolk.boatshed.com/broom_gemini-boat-77332.html

    And here is one that is reported to be 15' long -
    Broom Gemini Classic Speed Boat for sale from United Kingdom https://boats-from.co.uk/not-specified/broom-gemini-classic-speed-boat-74729

    Are you thinking about a windscreen similar to those shown in the links above?
    I guess you could put a 'hard top' on - raised a bit higher than the windscreen - but it would literally only have sitting headroom underneath it. You would pretty much have to crawl in underneath it.
     
  5. valvebounce
    Joined: Dec 2010
    Posts: 496
    Likes: 10, Points: 18, Legacy Rep: 124
    Location: manchester uk

    valvebounce Senior Member

    Hi,mine is like the yellow one ,but all white.Mine measures 14ft from the point of the bow to the transom.
    I don't want the roof to be only the same height as the windscreen,I want it high enough to sit under with a few inches clearance.My idea was to start off with a solid 20mm thick GRP board the width of the beam of the boat,and
    cut a hole in it to form a window frame that I can attach a roof to.It would be almost weightless and rigid enough to support the front of the roof.If I make frames for the sides for support,I don't intend to have Perspex in them,and
    maybe support the back end of the roof with slim pillars.The roof would be fibreglass,and glassed into the framework,
    and all the lot glassed onto the boat.(an open sided cuddy?)
    My seats swivel back to front if needed,and I have safety rails on the bow and down the gunnels.The more space I have for fishing rods the better.
    Thanks for your interest,it is much appreciated. "V"
     
  6. fallguy
    Joined: Dec 2016
    Posts: 2,072
    Likes: 127, Points: 63, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    Build it light!

    no glass

    foam construction; probably 20mm; no glass rec, but wondering about 12 oz biax (wet bagged would be light)

    aluminum pillars in stanchions

    anything heavy will cause rocking and easier capsize

    you might need something metal to hold the top up

    why not a soft top?
     
  7. valvebounce
    Joined: Dec 2010
    Posts: 496
    Likes: 10, Points: 18, Legacy Rep: 124
    Location: manchester uk

    valvebounce Senior Member

    The whole construction the way I have described it would only weigh 80 pounds max.
    A soft top would deteriorate very quickly.The height from the deck to the top of the roof would only be 4 foot to four foot six inches.We get more grimy weather than sunshine here in the UK,so I really need a permanent fix.
    I need to keep my GPS fishfinder and ship to shore radio out of the weather.
     
    fallguy likes this.
  8. bajansailor
    Joined: Oct 2007
    Posts: 351
    Likes: 49, Points: 28, Legacy Rep: 37
    Location: Barbados

    bajansailor Marine Surveyor

    Although you have mentioned that your boat is similar to the one in this link -
    Broom Gemini Classic Speed Boat for sale from United Kingdom https://boats-from.co.uk/not-specified/broom-gemini-classic-speed-boat-74729
    it would still be useful if you could post a photo of your boat as well.
    I would guess that for you to have 4' 6" headroom under your roof, it would have to be at least 12" above the windscreen on the boat shown in the link (?)
    Re a windscreen, are you going to have a flat screen (ie without the curved sides as in the link)?
    Re your roof, if you incorporate some camber curvature in it, this will make it much stiffer in comparison to a 'flat' roof - and also give you a mit more headroom in the middle.
    Be aware that any 'solid' structure will stand out a lot more (possibly making the boat look top heavy, as well as being heavier) in comparison to a canvas bimini type of roof.
     
  9. fallguy
    Joined: Dec 2016
    Posts: 2,072
    Likes: 127, Points: 63, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    80 pounds is a bit more than what I would build, but should be fine

    sounds like a good project for a drier ride

    I was out fishing in 0 degree weather and good winds last weekend...brrr 141A1A49-AB18-4199-AFBC-08EACE6271B2.jpeg
     
  10. valvebounce
    Joined: Dec 2010
    Posts: 496
    Likes: 10, Points: 18, Legacy Rep: 124
    Location: manchester uk

    valvebounce Senior Member

    It looks pretty cold,I'm 74yrs old,and not as tough as I used to be,I think these days I would be classed as a Fairweather fisherman.
    The boat has been stripped back to the basics,no carpets or fancy dash to the era fittings,just 6 rodholders,and good quality front seats.
    It's 75 miles to the sea from where I am,so it ends up a long day.
     
  11. valvebounce
    Joined: Dec 2010
    Posts: 496
    Likes: 10, Points: 18, Legacy Rep: 124
    Location: manchester uk

    valvebounce Senior Member

    The screen is going to be flat,the fibreglass sheet I have for the roof already has a camber in it,it came off another boat front hood/bonnet.
    A Bimini wouldn't suit the purpose,I need cover for the GPS fishfinder and ship to shore radio.
    I will incline the front screen at about 15% for a bit less wind resistance.I don't have a bad eye for lines,so i think I can make the structure blend in and not look too obstrusive.The boat is very strong and stable,so I think it can handle the extra weight.
     
  12. bajansailor
    Joined: Oct 2007
    Posts: 351
    Likes: 49, Points: 28, Legacy Rep: 37
    Location: Barbados

    bajansailor Marine Surveyor

    Fallguy's weather certainly does look very cold - I hope that the temperature mentioned is Centigrade rather than Fahrenheit!
    Re the mast on the bow in the photo - are the two reels on it for fishing? I'm intrigued as to how they are employed.

    VB, do you go fishing in the Irish Sea or North Sea? Manchester seems to be pretty much in the middle of the country, so a long drive east or west to the coast.
    You had mentioned "My idea was to start off with a solid 20mm thick GRP board the width of the beam of the boat, and cut a hole in it to form a window frame that I can attach a roof to". Sorry, I am a bit dense - is this for the front panel of the windscreen, and you will then cut apertures in it for two windows? Is it really 20 mm of solid fibreglass (as opposed to say GRP with a foam core)?
    Re supporting the aft end of the roof, the easiest way might be a couple of tubular aluminium pillars?
     
  13. fallguy
    Joined: Dec 2016
    Posts: 2,072
    Likes: 127, Points: 63, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    Some gps will not work through a roof there my friend. You might need an antennae; just so you know.

    The temp was 32F,0C with 15 mph winds...very cold. We had to find suitable shore or the sea was too rough far from... The mast is a set of planer board reels. The boards are deployed to about 100 feet p&s and a ring with a release deployed each side. The guide uses 80 pound fluorocarbon leaders to catch 50-60# muskellunge. The baits dove heavy and so they are not run far from the boat. A 45' line runs 15' down (or so).
     
  14. fallguy
    Joined: Dec 2016
    Posts: 2,072
    Likes: 127, Points: 63, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    Solid 20mm frp is heavier than needed, btw.

    A foam core of 12-20mm, with glass each side would work. The 12mm core might be thin for the roof, but we don't know dims afaik.
     

  15. valvebounce
    Joined: Dec 2010
    Posts: 496
    Likes: 10, Points: 18, Legacy Rep: 124
    Location: manchester uk

    valvebounce Senior Member

    My GPS fishfinder is a Lowrance,with the bullet skimmer.I have a line of sight antennae fitted for the radio.
    I have already got the 20mm marine ply,which is covered both side with Fibreglass(white)
    The roof fibreglass sheet is about 5mm thick..
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.