Please check out this design. 27 foot aluminum pilothouse.

I am having a 27 long 8 foot wide aluminum pilothouse built. I would like to power with a 300 outboard on a 6 inch set back jack plate. From what I have done calculation wise heavy load including the motor fuel and 5 people the boat will be around 8,000 lbs. Here are some renderings for reference. I tried to make a pretty aggressive modified V so with the 14 degrees in the back it can carry the load well and be stable at rest. If I run the trim tabs down and let the front eat I am hoping to smooth stuff out when its nasty. The only issue I am foreseeing is the tendency to broach which I will have to be cognizant of. Any recommendations for design changes? Will a 300 be enough to have a decent cruise speed?

 

I will also step up to a 350 if need be. I would like to stay at 300 if possible. If I can cruise around 22-25 mph I would be happy with that. I am also considering some longitudinal strakes to promote tracking and help prevent broaching does this seem like a valid idea?

 

Suggest you re-think those chine flats.

 

I know they are quite a bit wider than most. I pushed them back as far as I could. Do you see them causing any problems besides a rougher ride?

 

I don't think this is a wheel that needs to be re-invented. Besides slamming there is the specter of quirky handling from the unconventional hull.
Don't get hung up on specific deadrise numbers then stuff it up by adding wings.

I once built a boat to a bad design and the result was a huge waste of time, labor and material. At least it was just a small dinghy.

 

What would you suggest for modifications to the planing surface to ensure the best possible stabilty? Stick to 5-6 inch hard chines? Should the angle be changed where spray redirection is no longer an issue?

What do you suggest for chine width to maintain stability at low speeds and rest? 5-6 inches? Should the angle be flattened where redirection of spray is not a concern?

 

You need the services of a professional. This is not a place for guesses or opinions from internet strangers.
If money is an issue, then you sure as heck can't afford to build an entire bad boat.

Myself I'd buy stock plans from a reputable design house.

Good luck.

 

I have professionals that will review the design before production. But my bet is there are much more knowledgeable people here. I'm sorry if I struck a nerve because I don't know my *** from my elbow apparently. I came here for the advice of some of the best in the business. I did not realize you got told your design is terrible then go pound salt.

 

I would appreciate it if someone would point me in the direction of a professional that is trusted on this forum. Multiple opinions before I pull the trigger was my plan. I'm willing to bet that some of the best are here or know some of the best in the business.

 

The unwillingness to accept constructive criticism is not an asset.

 

I am accepting it with open arms that's why i came here and asked you what would be better. Then proceeded to ask about a professional like you mentioned. How am I not accepting it? I didn't accept the dismissive nature of your response.

 

Chine flats are notoriously unpredictable when made so wide. On boats running faster than 15 knots, they are likely to pound like hell. I hate to tell you, but if boat design was poker, those chine flats were showing your hand before playin.

Most of the guys who come here ask for people to throw holy water on a design, and get upset when critiqued.

I don't have other than some reading knowledge about the chine flats, but they don't seem wise to me at 11".

The obvious problem with boat design...

There are 7.7 billion or so people on the planet, some of them with billions of dollars to finance exceptional boat designs. It makes little sense to design a boat hull these days. Many proven designs exist and on a budget of $100,000; there is no reason to take chances. A good plan can be found and modified inside to your wishes.

Another critique of the design. Why would you straight side? The likelihood of creating a wet boat is higher this way, too.

When someone gives you advice to find a proven design, it is actually exceptional advice.

 

Also, why only 8' wide? You want stability, a dry ride, but are 6" narrower than legal trailering. I have seen others do this in design as well

 

The reason this is happening is boat prices are so inflated here that no one can afford an aluminum boat. I have had to outsource to China. The difference in shipping from
something that fits in a container to roll on roll off is 7500 compared to 30,000. You are seeing many people trying to enjoy boating to the fullest without paying 200,000 for a medium sized pilothouse boat. So the 8 foot beam will become more and more regular until prices settle here. I was simply asking for input and in no way did I let it ruffle my feathers when told my design sucks. I asked for input then for a professional to help. I started this process two years ago and watched my quote double from every builder I talked to. I appreciate the input. I will rethink my process completely.

 

I understand the problems with shipping. I just wanted to know why you specified a wide, stable platform and then built narrow.

It sounds like you are letting the build be constrained by shipping logistics. I know a guy who did this and has been a little unhappy about it for 5 years.

Me!

My boat is designed to be taken apart and put on a semi. Similar, constrained to 8'6" wide cabin.

I believe Jacques Mertens has a similar boat 8' wide designed in plywood. Have you seen it? Sorry, not pilothouse. He said it would become unstable..