Converting Standard hull into bowrider

Put a few sandbags down under the bow to simulate the weight before you start, and know in advance how the boat will trim.
One bulkhead should be across where the windshield is. If you have a notch in that one, double the plywood, and keep the notch knee high, maybe even curved like a U. The forwardmost bukhead can be full (no notch), and should be back as far from the tip of the bow as will still allow TWO people to sit forward across from each other in the Vee. That keeps the weight as far back as possible. Put one halfway between the two to support the seat halfway.
How you detail out the winshield area is up to you. Once the bulkheads are installed, they get even more strength from strong seatbacks and risers and the seats themselves. Fasten all those parts well. They are all structural.
But of course put some bow weight in the boat before you do anything. Sand bags will do nicely. I'd put 200 kilos centered about where 2 people will be positioned. That allows for the added wood structure weight, some people, and gear. If the boat won't come up nice and level and then some with the more powerful motor, you're gonna be in trouble later. Kids love sitting out front, and they're pretty light, but with adults, put them first in the back or split between front and back, and then fill up the back before filling the front. But I guess you know that.

Regards, Alan

 

You are just looking for trouble. I have done a bowrider conversion and It takes a lot of skill and understanding of the structural components in the boat. The amount of work is exponential. I still say NO NO NO! You will thank me later.

 

Lots of work? That sounds exactly like school, except school is expensive.
when I was 18, I hitchhiked across the country and back. The amount of work, not to mention the danger, was expotential, compared to buying a plane ticket.
As I look back, however, I remember how my world opened up, the places I saw, the people I met. 33 states, camping in the Rockies, getting invited onto a movie set in LA, getting picked up by truckers, a gambler, an exotic dancer, the owner of the biggest Indian trading post in the world, hippies, yippies, ministers, outlaws, and on and on.
Youth is allowed to experiment. What they gain from it is not so apparent on the surface. One day, each move will be calculated, empirical wisdom listened to, and the end will always justify the means before the process even starts, or it won't start.
We become masters of safety and efficiency.

A.

 

Back again... but should be in bed by now

Davient:
By the looks of your last post (#15) I'd say your starting to learn what we're talking about. Be careful not to under-estimate our warnings. You are attempting to do something that you have been strongly advised against, and for good reason.

Marshmat mentions something about spinning out... (post #14). I, personally, have first hand experience with this phenomenon. It is not funny at all either... nor should it be taken light hearted. When I was offered the opportunity to buy the boat that I'm currently restoring I first wanted to "take it for a spin around the lake". A test drive. At full throtle, which was approx. 35 mph (measured by the boat behind us) the boat suddenly turned 180 degrees (a spin out). My buddy (who owned the boat) and I, were nearly thrown out of the boat...each and every time... literally !

This happened 3 or 4 times and I'm here to tell you... it is flat , F*#@ing scarry. I still bought the boat, but I know what caused this and I know how to fix it now too.

My dad taught me that "If you can imagine something... You can do it".​

But, that didn't mean that everything that you can imagine should be attempted.

If you insist on doing this, and it appears that you do, please pay heed to everyones advice... especially Allen's..."Put a few sandbags down under the bow to simulate the weight before you start".

Testing it by yourself will not tell you anything about how it will handle with the additional weight of other people in the boat... unless you do something like Allen has suggested.

Also, bare in mind that dispite what your initial intentions are, you will probably sell this boat at some time in the future. I hope that you keep in mind the safty of the new (Proud) owners who will more than likely be unsuspecting of the changes that you have made.

My best advice to you in this type of situation is this:
Consider the absolute WORST thing that can happen to you or anybody else that might be in your boat... and ask yourself... "Can I accept this ?"

I really don't want to sound negitive... because, I myself, have done soooo many things that everyone said "you can't do that". I succeeded most of the time but, it wasn't always inteligent.

 

For what it's worth...

Why screw up that boat with what your thinking ??? It's a great looking little boat just the way it is...

Change the seating to something a bit more modern, add your slightly bigger engine and call it good.... Put it on the water dude !!! Enjoy it and get something else to work on if you so desperatly need a project... Serious.

There are a lot of project boats out there to be had if one wants to look for them.

 

Hi guys,
I will definately be using the sandbags to simulate weight up on the front when I test drive the boat. Vic When you said that your boat span out, just out of interest what caused that and how will you repair it? Alan, thank you for your generous input I will definately be refering to it during my project. Not too much longer now till I get it, today I bought my bilge pump, fishing rod holders and hummingbird fishfinder. Do you guys know how I would fit
the pump into the hull? my idea would be to cut a small section in the rear section of the floor, just infront or the motor, place the pump inside the hull, seal up the floor with bolts and run the wires/hose out of the same sealed hole with a good amount of clear silicone? I attached another picture of my idea.

Dave

 

Dave:
To answer your question about the "spin out" please see http://boatdesign.net/forums/showthread.php?t=15793&highlight=hooked transom

You'll see my original question and also the answers that I recieved.

As for your bilge pump... Don't seal it under the deck / floor. It should be accesable for cleaning (you will get some kind of debree under there) and general inspection.

Make an easily removable cover ... I'm surprised that there isn't something like this already on your boat.

 

Finally started!

Hi guys,

I finally sold my duck and have created space for my new boat in my garage to start work on. So far I have cut the front off and built up the two front consoles. I've used marine ply for the wood/epoxy glue and brass screws. I'll post a few pictures, hopefully someone might be able to use it as a reference in the future. And suggestions or comments will be appreciated.
Dave

 

If I can offer a few tips and advice from building five power boats before...

You have to ensure the boat is a stiff unity that will not flex. If the boat is not supported properly in it's length, the sides will tend to push out and the rear will try to overtake the front.

Another problem you may encounter if the boat is not properly supported across is twist in waves. The rear and front may not be at the same angle any more. This has the tendency to delaminate the old glass and the new glass from one another.

The only way (in my humble opinion) to regain ample strength (as well as stiffness) without delaminating problems is if you use the structure as part of the features AND glass the interior out completely with a few layers. If you only glass your chair in place with a 150mm strip around it's base for instance it may feel sturdy but I can guarantee the chair is going to break loose even after crossing a few other boats wakes. I'm talking from first hand experience. Another thing I've found ok for joining old parts to new is to do apply say 3 layers of glass, rivit properly (100mm appart, 5.8mm allu or SS rivits) and cover with another two layers before the first gets completely dry so you won't see the rivits and get a decent bond. You cannot rivit in the hull, of course, but you can grind it course and glass the whole bottom interior surface so that both can move and deform without delaminating.

As I've indicated in another thread, I'll never use any kind of wood in a boat again.

You have to keep in mind that the forces on the boat's hull is far more than one anticipates. The weight of a small car as in your case, coliding with a wave is like driving up and down stairs with your car without real suspension, everything just wants to rip appart. It gets worse if the wind picks up and the boat bounces on the waves when you head for shore, hundreds of little hammers hitting the hull.

Provide for some floatation so the boat won't sink if it gets full of water. Freak weather and one wake later you may have a ton of water in the boat. Seen it myself, grandfather, father and son, none wearing life jackets. Bloody idiots. Had to spend my fishing time to save them

I can see some support under the gunnel, but this is by far not nearly strong enough even if you glass it some more

 

Sorry, I forgot to say, try to finish the glass in one go instead of doing one piece every other day. If the glass dries out too much before the next layer you're sitting with the same problem of possible delamination all over. See the resin spec for this info.

 

74 Crestliner Open Bow

Gentlemen, I have read alot on this thread about Dave's boat I the topic was interesting and got me thinking about my boat. I have a 74 Crestliner Runabout with the 302/888. I am curious to know if my boat could easily be converted to an open bow, because it already had the split windshield with opening and closing mid section (factory) and dash is already split, the bow currently is home to the 18 gal fuel tank. What are your thoughts.
I am also going to be removing the 2 lounge seats and installing to swivel seats, and redoing the engine compartment to include a bench in front of the engine compartment, and utilize the waisted space on both side of the engine for storage compartments.

 

You got plenty of life insurance ???

You are wasting your time and going to get into a lot of striff !
Take the boat out onto the water and sit 2 adults on the fore deck In the approx possition where they would be if it was a bow rider then put 2 more adults in the two front seats and get some one to take a picture of the boats trim !! all veiws !!! front ,side,and other side and a back veiw as well !!,see if the motor has enought water !! .
a front loaded boat is a dangerous boat !!, one extreme is it could simply nose dive and fill with water ! it could broach on a smallish wave and the possability of rolling on its side to the point of even tossing someone outfrom the other part of the boat !
i think you will get the idea pretty quickly you really are pushing brown stuff up a steep hill with a sharp pencil wouldnt you say ??
Then there all the hassles of building and strengthening the front of hull .

 

This guy can do this, though it's not the easiest way to get a bow rider, so what. Let him learn they way we all did.

The primary concern isn't weight, as he cuts away about what he'll put back in, so balance will still be there and the boat isn't going to do any acrobatics, in spite of the overly emphasized concerns. In fact, it's very probable this hull shell also came with a bow rider option (as most do) with just the deck cap being the only appreciable difference.

My primary concern is athwart stiffness, which was provided by the dash board portion of the deck cap. With this cut away, you lose a lot of hull shell rigidity and athwart stiffness. It needs to be replaced. Manufactured bow riders do this with lots of triangulation in the bow seating, just forward of the helm and passenger seat. This firms up the hull shell a good bit, but even with this, most bow riders don't have as much athwart stiffness as a runabout deck cap. Having a 20 year old bow rider, means the center, opening section of the windscreen not closing properly, is standard fair for this type of boat.

My observations of the project photos would suggest to abandon trying to use so much of the original deck cap parts. Locating the dash panel halves on little chunks of wood, seems an extraneous effort. It just needs to be heavily tabbed, but more importantly these halves need to be triangulated into the hull shell. The reasonable approach would be to use two boxes, bonded to the hull shell that support the dash pieces, forming a 3 sided affair. On the forward side of these boxes, you work in the bow seating, again all well tabbed to the hull shell. It would also be wise to incorporate a step, so the lower bit of the two dash boxes can be tied together with a partial bulkhead, say about 8" tall. The bow seating should have at least an athwart ring frame or bulkhead partition, which will help support he casting deck/bow rider seating area.

Run down to the local marine and have a lot at different bow riders and see how they handle the forward seating area. All the angles and perpendicular shapes are intentional, so to impose some athwart rigidity to this inherently weak arrangement. Pay attention and mimic these ideas, as they're done for a good reason, besides you can get free ideas an inspiration too.

You don't need sand bags nor anything else, the voices behind the curtain may be suggesting. Just splash the boat, putter about, try to WOT blasts and if you haven't any major leaks or issues, get a couple of friends drunk (helps with any eventual law suits, trust me on this) then invite them out for test ride. Yes, having well fed, drunken buddies aboard, sitting in the bow will make getting "out of the hole" a little problematic, but not imposable, just slower. The logical way to "take off" is to have the crew in the cockpit with you, until you're fully up on plane, then they can move forward to the bow seating area.

I say keep going for it and if you have to screw up, do so on the side of having too much tabbing, on the parts bonded to the hull shell. Have fun, keep us posted and some more pictures as you progress would be nice.

 

SO..... What happened? The original post and the pictures were from 2007. Five years later, did he actually finish, or did he give up after realizing that everyone was right? Or did he kill himself testing the boat out?

He would have probably enjoyed building a boat from scratch more.

-TH

 

I have decided I don't have the time to make my boat an open bow, although after reading some of these posts I have decided to investigate my model and see if it was built to be either open or closed bow. Anyway I have a real project I would like some help with maybe even a design. I would like to remove the old engine cover and build one that covers the width of the boat with storage compartments on each side where there is waisted space, directly in front of the new engine compartment I would build a bench for seating 3-4 people with storage underneath as well. I would remove the 4 loung seats and replace with 2 swivel style seats. Any ideas I have an idea but would like other ideas and input please. I am a newbie to boat restoration and I just want something simple and cost effective.